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Ramin Hashemi

Iran University of Science & Technology, Mechanical Engineering, Faculty Member

University of Tehran, Mechanical Engineering, Alumnus

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Ramin Hashemi is an associate professor of mechanical engineering at the Iran University of Science and Technology. He got his Ph.D. in Mechanical Engineering from the University of Tehran in 2012. He currently does research in Mechanical Engineering and Materials Science. Their current projects are 1- Fabrication of clad metals (bimetals or multilayer sheet) 2- Experimental evaluation of forming limit diagram (FLD) and mechanical properties of Nano/ultra-fine grained materials fabricated by the accumulative roll bonding process. 3- Fabrication of metallic foils for different applications and determination of corresponding forming limit diagrams and mechanical properties
Address: Tehran, Iran, Islamic Republic of

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Papers by Ramin Hashemi

Predicting 3D printed plastic part properties: A deep learning approach with thermographic and vibration data fusion

Expert Systems with Applications, 2024

Additive Manufacturing (AM) holds transformative potential for the manufacturing industry, yet it... more Additive Manufacturing (AM) holds transformative potential for the manufacturing industry, yet its widespread adoption is hindered by inconsistent product properties. This study addresses this challenge by pioneering a novel predictive method to assess the impact of in-process sensing on part property prediction in Fused Deposition Modeling (FDM), serving as a representative case study. Focused on five critical mechanical properties, including surface roughness, tensile strength, elongation at break, micro-hardness, and warpage, we systematically explore various sensor combinations by integrating Inertial Measurement Unit (IMU) sensors and a thermal camera with machine setting parameters. Utilizing deep learning models, specifically hybrid Convolutional Neural Network and Long Short-Term Memory (CNN-LSTM) architectures, we encode time-series sensor data into signal images and evaluate performance across different sensor configurations. Our best-performing model achieves an impressive 99% correlation in predicting tensile strength, albeit with less robust performance in predicting warpage and micro-hardness, suggesting additional influencing factors. Furthermore, the employed signal imaging technique outperforms a handcrafted feature selection alternative. These findings carry significant implications for advancing the broader adoption of AM in critical applications, addressing challenges associated with inconsistent product properties and unlocking its full potential.

Numerical and experimental study of three-layered Al 1050/Mg AZ31B/ Al 1050 sheets formability considering strain and stress conditions through single point incremental forming

Materials Today Communications, 2024

This article examines the formability of 3-layer Al 1050/Mg-AZ31B /Al 1050 sheets experimentally ... more This article examines the formability of 3-layer Al 1050/Mg-AZ31B /Al 1050 sheets experimentally and numerically. Mg AZ31B, with its high strength-to-weight ratio, and Al 1050, with its formability and lightweight, are attractive industrial metals. In the experimental method, the forming limit diagram (FLD), the Forming limit angle (FLA), and the fracture depth were investigated for the 3-layer and base samples with two pyramid and cone geometries. The results showed that the ductility in the cone geometry is higher than that of the pyramid. Also, by comparing the FLD of the 3-layer sample to the base sample, the results showed that the formability of the 3-layer sample increased compared to the Mg-AZ31B base sample. In contrast, the formability decreased compared to the base sample of Al 1050. Numerical studies for predicting the FLD using the SPIF method were carried out using Abaqus software. The numerical techniques considered the second deviation minor strain (SDMIS), second deviation effect strain (SDEF), second deviation thickness (SDT), and second deviation major strain (SDMS). The results showed that the highest accuracy occurred for the SDT method compared to other numerical methods. To remove the effect of the strain path on the numerical analysis for predicting the FLD (from the stress analysis method), a second deviation of von Mises stress (SDVMS) was used. By examining the results, it was found that the results of numerical methods considering stress could be highly accurate.
Graphical Abstract

Multipoint forming process of aluminum sheet considering its forming limit diagram: Experimental and numerical investigations

Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications, 2024

Considering the significance of sheet metal forming in various industries, metal sheets, and ligh... more Considering the significance of sheet metal forming in various industries, metal sheets, and lightweight alloys find extensive applications. It is essential to predict the formability limit of sheets. Whereas the previous studies used the Nakazima test, this study aims to determine the forming limit diagram (FLD) numerically and experimentally using multipoint forming, considering the strain path's effect on formability. Also, it is compared with the conventional FLD obtained via the Nakazima test. The results show that multipoint forming improves sheet metal forming. The experimental FLD for an AL 2024-O sheet with a 12 mm pin size was found to have higher formability than that obtained from the Nakazima test. The effect of the polyurethane layer on the forming limit diagram was investigated. The experimental results showed that the polyurethane layer prevents local strain and increases the limits on the forming limit diagram. The numerical forming limit diagram was predicted by the second derivative method. Finally, the experimental results were compared with the numerical simulation results, showing that the results had an agreement above 90%. This method can be used as a reference for assessing the effectiveness of the multipoint forming technique.

Microstructure investigation and optimization of process parameters of ultrasonic welding for Al–Cu dissimilar joints using design of experiment

Journal of Materials Research and Technology, 2024

Ultrasonic Metal Welding (UMW) employs high-power ultrasonic vibrations to join thin metal sheets... more Ultrasonic Metal Welding (UMW) employs high-power ultrasonic vibrations to join thin metal sheets of different materials, effectively addressing the thermal damage issues associated with traditional welding methods. This study aimed to optimize the joining of thin aluminum (Al) and pure copper (Cu) metal sheets using high-power ultrasonic vibration. The investigation focused on the effect of input parameters, including time, static pressure, and welding power, on the output parameter of joint strength. The results indicated that the welding time had the most significant effect on the load obtained from the Tensile-shear test. The optimal condition was determined to be a welding time of 0.98 s, a pressure of 2 bar, and a power of 85%, resulting in a maximum predicted tensile-shear test load of 753.3 N, with an error value of 11.4% obtained from the software. Microscopic images reveal that the welding mechanism in ultrasonic welding involves continuous plastic deformation, dispersion of oxide layers, and the formation and extension of micro-bonds along the weld line.

Investigation and optimization on the formability of aluminum 1050/ stainless steel 304L bilayer sheets fabricated by cold roll bonding considering the Box-Behnken method

Journal of Materials Research and Technology, 2024

Composite metal sheets have found extensive applications thanks to their high corrosion and wear ... more Composite metal sheets have found extensive applications thanks to their high corrosion and wear resistance, as well as greater strength, stiffness, and formability relative to the base sheets. Stainless steel composite sheets account for over 80% of the metallic composite sheets. Their higher performance and lower costs have increased their applications in the food and automotive industries. This study experimentally addressed the formability of the Al 1050/Stainless Steel 304 L bilayer sheets prepared through the cold rolling process. After designing the experiment using the response surface method, considering the layer thickness and reduction ratio of the rolling process, the bilayer sheets were prepared using the cold roll bonding process. Formability included the forming limit diagram, the magnitude of FLD 0 , and elongation, which were derived by Nakazima and tensile tests. Then, the formability was optimized as a function of input parameters considering the Box-Behnken method. To this end, a new criterion was presented to compare the formability of the sheets. This criterion can be used to assess the formability of a sheet considering various loading modes. Microstructural observations justified the variations in the formability of the bilayer sheets against the input parameters, i.e., thickness ratio and reduction ratio. The results indicated that the formability of the Al 1050/Stainless Steel 304 L bilayer sheet (i.e., safe forming region) reached its maximum value at t Al = 4mm; t SS = 0.8mm; and r = 45%.

Novel hybrid 3D-printed auxetic vascular stent based on reentrant and meta-trichiral unit cells: finite element simulation with experimental verifications

materials today communications, 2023

In this study, a novel re-entrant meta-trichiral auxetic (RMCA) vascular stent with improved mech... more In this study, a novel re-entrant meta-trichiral auxetic (RMCA) vascular stent with improved mechanical properties was designed by combining three auxetic unit cells: re-entrant, trichiral, and anti-trichiral. The in-plane tensile behavior of RMCA structure was investigated through finite element analysis and experimental tests were performed to verify the finite element analysis (FEA) results. 3D printing was employed to fabricate the samples. The effect of various geometric parameters on the in-plane behavior of RMCA structure, including the stress-strain curve and Poisson's ratio, were studied using FE analysis. The highest value of negative Poisson's ratio obtained for RMCA structure was equal to-4.91, which is a stunning value among auxetic structures. After that the vascular stent was proposed using the most appropriate structure determined by the parametric investigation. Finite element analysis (FEA) was conducted to evaluate the behavior of the stent during the deployment process (angioplasty), and interaction between the vascular stent, artery, and plaque. The dogboning, foreshortening, and recoil of the vascular stent were evaluated using the FEA results. Also, bending flexibility of the vascular stent was investigated based on FEA and three-point bending tests.

Novel hybrid 3D-printed auxetic vascular stent based on re-entrant and meta-trichiral unit cells: Finite element simulation with experimental verifications

Materials Today Communications, 2023

In this study, a novel re-entrant meta-trichiral auxetic (RMCA) vascular stent with improved mech... more In this study, a novel re-entrant meta-trichiral auxetic (RMCA) vascular stent with improved mechanical properties was designed by combining three auxetic unit cells: re-entrant, trichiral, and anti-trichiral. The in-plane tensile behavior of RMCA structure was investigated through finite element analysis and experimental tests were performed to verify the finite element analysis (FEA) results. 3D printing was employed to fabricate the samples. The effect of various geometric parameters on the in-plane behavior of RMCA structure, including the stress-strain curve and Poisson's ratio, were studied using FE analysis. The highest value of negative Poisson's ratio obtained for RMCA structure was equal to-4.91, which is a stunning value among auxetic structures. After that the vascular stent was proposed using the most appropriate structure determined by the parametric investigation. Finite element analysis (FEA) was conducted to evaluate the behavior of the stent during the deployment process (angioplasty), and interaction between the vascular stent, artery, and plaque. The dogboning, foreshortening, and recoil of the vascular stent were evaluated using the FEA results. Also, bending flexibility of the vascular stent was investigated based on FEA and three-point bending tests.

Optimizing FDM Process Parameters: Predictive Insights through Taguchi, Regression, and Neural Networks

Physica Scripta, 2024

Fused deposition modelling (FDM) is a popular additive manufacturing process used for rapid proto... more Fused deposition modelling (FDM) is a popular additive manufacturing process used for rapid prototyping and the production of complex geometries. Despite its popularity, FDM's susceptibility to variations in numerous process parameters can significantly impact the quality, design, functionality, and mechanical properties of 3D printed parts. This study explores thirteen FDM process parameters and their influence on the mechanical properties of polylactic acid (PLA) polymer, encompassing surface roughness, warpage, tensile and bending strength, elongation at break, deformation, and microhardness. The optimum parameters were identified alongside key contributors by applying the Taguchi method, signal-to-noise ratios, and analysis of variances (ANOVA). Notably, specific FDM parameters significantly affect the surface profile, with layer thickness contributing 32.65% and fan speed contributing 8.59% to the observed variations. Similarly, warping values show notable influence from nozzle temperature (29.53%), wall thickness (16.74%), layer thickness (16.56%), and retraction distance (12.80%). Tensile strength is primarily determined by wall thickness (31.83%), followed by infill percentage (26.73%) and infill pattern (16.18%). Elongation at break predominantly correlates with wall thickness (44.82%), with a supplementary contribution from nozzle temperature (10.90%). Microhardness lacks a dominant parameter. Bending strength variations primarily arise from layer thickness (38%), wall thickness (37.6%), and infill percentage (9.17%). Deformation tendencies are influenced by layer thickness (19.20%), print speed (11.37%), wall thickness, and fan speed (10.9% each). The optimized dataset of FDM process parameters was then employed in two prediction models: multiple-regression and artificial neural network (ANN). Evaluation based on the correlation coefficient (R 2) and root mean squared error (RMSE) indicates that the ANN model outperforms the multiple-regression approach. The results indicate that precise control of FDM parameters, coupled with ANN predictions, facilitates the fabrication of 3D printed parts with the desired mechanical characteristics.

Study of single point incremental forming limits of Al 1050/Mg-AZ31B two-layer sheets fabricated by roll bonding technique: Finite element simulation and experiment

by Ramin Hashemi and Ramin Hashemi

Journal of Materials Research and Technology, 2024

In this work, for the first time, the two-layer Aluminum (Al 1050) and magnesium (AZ31B) sheet we... more In this work, for the first time, the two-layer Aluminum (Al 1050) and magnesium (AZ31B) sheet were used in the single point incremental forming (SPIF) process. Due to the high strength-to-weight ratio of the Al 1050/Mg-AZ31B sample, today it is used in significant industries such as automotive and aerospace. The finite element simulation process was carried out using the Abaqus Software considering five approaches to determine forming limits. These approaches were forming limit diagram criterion (FLDcrt), effective strain rate (ESR), second derivation of thinning (SDT), Major strain rate (MSR) and Thickness strain rate (TSR) methods. The results showed that the failure prediction in the FLDcrt method was more accurate than other methods. The thickness distribution process was carried out both by simulation and experiment to validate the simulation results. The results show a good agreement between simulation and experimental results. Finally, the results obtained from the SPIF process were compared with the FLD results of the conventional hemispherical punch test, and it was observed that the FLD was higher in the SPIF process. Moreover, the layer arrangement, which affects formability, was investigated. The results showed that the FLD with Mg-AZ31B/Al 1050 arrangement fails in higher strains compared to Al 1050/Mg-AZ31B. After validating the simulation results, the parameter effect of the stepdown and tool diameter on the two-layer formability was investigated by the design of experiment. Considering the greater importance of the step-down and tool diameter effect on the created stresses and forming time compared to other parameters, their effect will be investigated. The results showed an optimal condition for the tool diameter, but an opposite relationship with formability was obtained for the step-down.

$Research paper thumbnail of The role of applied strain and volume percentage of components on mechanical properties and fracture toughness in multilayered Al/Mg composite fabricated by the accumulative roll bonding process$

The role of applied strain and volume percentage of components on mechanical properties and fracture toughness in multilayered Al/Mg composite fabricated by the accumulative roll bonding process

Materials Research Express, 2021

In this study, for the first time, the effect of applied strains and volume percentage of compone... more In this study, for the first time, the effect of applied strains and volume percentage of components of layered composite on the mechanical properties and fracture toughness of Al/Mg were investigated experimentally. The multilayered Al/Mg were produced by the accumulative roll bonding (ARB) process. For the investigation, three Al/Mg composites with different volume percentages (25%, 50%, and 66.6%Al) at different applied strains (0.8–3.2) were produced. The experimental evaluation included microscopic examination by optical microscope imaging, uniaxial tensile test, and plane strain fracture toughness. As the applied strain for all three composites increased, plastic instability in the magnesium reinforcement intensified, but due to the low thickness of the Al layers compared to the Mg layer, uniform structure of Mg distribution in Al for all three composite was not achieved. Also, by adding Al layers to the primary composite, a lower shear strain was applied to the magnesium rein...

Fabrication of AA1050/CP-Cu Bimetallic Tubes using Parallel Tube-Shaped Channel Angular Pressing Technique and Assessing its Mechanical Properties and Microstructure

Transactions of the Indian Institute of Metals

Nowadays, the need to use multi-layered materials in various industries due to their unique prope... more Nowadays, the need to use multi-layered materials in various industries due to their unique properties, such as resistance to wear, corrosion, and weight lightening, is augmenting. In this paper, the production of bimetallic aluminum (AA 1050) /commercially pure Cu tubes by cold parallel tube-shaped channel angular pressing (PTCAP) process was considered for the first time. The PTCAP process was performed in three passes, and the bonding properties, microstructure, and microhardness were evaluated in each pass. The microstructure and mechanical properties of PTCAPed samples were examined by Optical microscopy (OM), scanning electron microscope (SEM), Energy Dispersive X-ray Spectroscopy (EDS), Vickers microhardness test, and shear punch test. According to the results, the Cu and Al PTCAPed tubes&#39; microhardness was improved by 125% and 87%, respectively. Besides, after three passes, the mean size of grains of the copper tube decreased from 58 to 6μm. Therefore, based on the Hall-Petch relationship, the main reason for the increase in microhardness can be stated as the significant reduction in grain size. According to the shear punch test results, after three passes of PTCAP, the shear strength between the two layers was increased by 208%. Finally, both tubes were well bonded as a bilayer tubes at higher passes.

Analytical and numerical investigation of Bulge test in bimetallic sheets

Application of an Extended Strain-Based Forming Limit Curve in Finite Element Simulation of X-Branch Hydroforming

This work presents a numerical framework that implements extended forming limit curves (FLCs) to ... more This work presents a numerical framework that implements extended forming limit curves (FLCs) to predict bursting during tube hydroforming process. Here, at first, the extended FLC is calculated for tube material based on the generalized M-K model that takes the through thickness normal stress into account. As a case study, the forming process of X-shaped branch is simulated by ABAQUS/EXPLICIT commercial finite element package. The required incremental plastic equivalent strain and strain ratio, which are required for comparison with the computed extended FLC, are extracted from the results of FE simulation. The robustness of the extended FLC in prediction of necking is tested by comparing with the published experimental data where a satisfactory agreement is found.

Printing strategies to fabricate a disk through the fused deposition modelling method

Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications, 2023

The Fused Deposition Modelling (FDM) technique is widely used in different industries due to its ... more The Fused Deposition Modelling (FDM) technique is widely used in different industries due to its low cost and ability to produce complex geometries from polymers. In this technique, some manufacturing parameters are essential because of their effects on the mechanical performance of the final fabricated part. The current study investigated the impact of path strategy and printing speed, two key manufacturing factors, on the mechanical performance of printed disks. Six types of path strategies of rasters corresponding to the loading direction, namely unidirectional-vertical, unidirectional-horizontal, unidirectional-45, cross, cross-45, and concentrate, were used for printing some disks, and compressive tests were done on them. The results showed that these path strategies' average compressive failure loads were 2955, 4957, 2342, 4640, 3971, and 5893 N, respectively. The lower compressive strength of the unidirectional path pattern was due to the weak zones that were located between the printed layers and rasters. Besides, three printing speeds of 40, 60, and 80 mm/s were considered to fabricate the disks with a concentrate path pattern, and compressive experiments were performed. The results showed that the 40 mm/s printing speed conducted a compressive failure load of 4544 N, while 60 and 80 mm/s resulted in 3008 and 2828 N, respectively. Finally, inter-layer strength as a major factor in controlling the compressive strength of the disks was comprehensively discussed.

Experimental investigation of parameters in fused filament fabrication -3D printing process of ABS plus using response surface methodology

The International Journal of Advanced Manufacturing Technology, 2023

3D printing by Fused Filament Fabrication (FFF) can produce complicated products often used for p... more 3D printing by Fused Filament Fabrication (FFF) can produce complicated products often used for prototyping. The major challenge for this technology is the production of functional parts with suitable mechanical properties. It is possible to improve the mechanical properties of the parts produced with FFF by correctly selecting and combining the process parameters. In this research, acrylonitrile butadiene styrene plus (ABS plus) samples with three variable parameters, including infill density, layer thickness, and raster angle, were printed to evaluate the ultimate tensile strength (UTS) and fracture strain in the tensile test. The two-dimensional digital image correlation (2D-DIC) technique measured the full-field surface strain. Before starting the test, the appropriate contrast of the sample surface was ensured using a histogram. The results were validated and predicted using response surface methodology (RSM). Prediction of the results using the quadratic model reveals that the mean error obtained for UTS and fracture strain was 2.96% and 2.87%, respectively. The analysis of variance (ANOVA) was used to validate the model. Also, the effect of the individual and interaction parameters on the response was examined. The raster angle parameter, directly related to transferring the load to the sample, was recognized as the most crucial parameter affecting both responses. The optimization results to maximize UTS and fracture strain values indicate 73.42% infill density, 0.227 mm layer thickness, and zero-degree raster angle, leading to UTS of 34.92 MPa and fracture strain of 3.59%. Finally, the field emission scanning electron microscope (FESEM) is employed to investigate the failure mechanism in the samples.

Review of selective laser melting of magnesium alloys: advantages, microstructure and mechanical characterizations, defects, challenges, and applications

Journal of Materials Research and Technology

parameters. The characterization of the primary powder is divided into two categories: morphology... more parameters. The characterization of the primary powder is divided into two categories: morphology and particle size, along with chemical composition. Morphology and chemical composition play an essential role in the final part by affecting the alloy&#39;s flowability, oxidation, and ignition. Characterization of properties is also reviewed in three general densifications, mechanical properties, and microstructure of SLMed samples and their dependence on parameters and input materials. Finally, the defects and challenges are briefly discussed, and the applications of Mg alloys in two widely used areas, including automotive and medicine, are presented.

An experimental investigation of mechanical properties, forming limit curves, and bending behavior of aluminum-polymer sandwich composites

Materials Research Express, 2021

This study aimed to investigate the forming limit diagrams (FLDs), mechanical properties, and ben... more This study aimed to investigate the forming limit diagrams (FLDs), mechanical properties, and bending behavior of the three kinds of sandwich composites. The core layer in all sandwich sheets consisted of polyethylene, and just the skin layers were chosen to be AA5754 or AA3105. The results showed that the sandwich sheets are an appropriate choice to be used instead of the monometallic sheets. According to the 3-point bending test results, the flexural strength of the AL 3105/Polyethylene/AL 3105 sandwich composite is about 30 percent less than the AA3105 monometallic layer. Also, the formability of the metallic sandwich composites with non-identical skin layers was studied. The results demonstrated that using one layer AA 3105 and one layer AA5754 instead of AA5754 for both skin layers, although formability decreased about 11% in the plane strain region, the cost of fabricating the composite was decreased sheet reduces almost 75%. As a result, using skin layers with the different g...

Formability of Tri-layered IF240/AZ31/IF240 Composite with Strong Bonding: Experimental and Finite Element Modeling

Journal of Materials Engineering and Performance, 2021

In this work, the formability of a hybrid material of Interstitial-Free 240 (IF240) steel and AZ3... more In this work, the formability of a hybrid material of Interstitial-Free 240 (IF240) steel and AZ31 magnesium alloy as IF240/AZ31/IF240 tri-layered sheets was investigated. For this purpose, the bonding feasibility of the high-formability IF240 steel and low-formability AZ31 sheets was first assessed. Then, the hot formability behavior of the manufactured laminated composite was evaluated. The rolling of the preheated samples established the layer bonding. The bonding strength was determined using the shear punch test. The texture and its effects on the forming behavior were studied using the x-ray Goniometry method. Nakazima dome tests were employed at ambient and elevated temperatures to determine formability and forming limit curves. The forming process simulation was performed by ABAQUS/Explicit solver, and the results were compared with the experimental data. The results showed that post-annealing time and thickness reduction have significant impacts on the bond strength. The formability of the composite laminate improved significantly by an increase in the temperature. Simulation results of the composite forming behavior were in fair agreement with the experimental results.

Finite element simulations and experimental verifications for forming limit curve determination of two-layer aluminum/brass sheets considering the incremental forming process

Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications, 2021

In this paper, forming limit diagram (FLD) of aluminum/brass two-layer sheets through an incremen... more In this paper, forming limit diagram (FLD) of aluminum/brass two-layer sheets through an incremental forming process (ISF) was studied numerically and experimentally. At first, the two-layer aluminum 1050/brass (65% copper) sheets were fabricated using the roll bonding process. Also, the finite element simulations of the incremental forming process with ABAQUS software were utilized to predict the FLD. For this purpose, the criterion of the second derivative of the equivalent plastic strain was used to predict fracture. Finally, the numerical simulation results were compared with the experimental results. For instance, comparing experimental and numerical FLD0 values for the formed samples with forming angle 62.5-degree showed a 7% difference. However, the difference was negligible, and numerical simulation results could be used with an appropriate reliability coefficient. The effect of sheet arrangement towards tools was then investigated. It finds out from the experimental results...

An Experimental Study of Fracture Toughness for Nano/Ultrafine Grained Al5052/Cu Multilayered Composite Processed by Accumulative Roll Bonding

Journal of Manufacturing Science and Engineering, 2018

In this study, ultrafine grained Al5052/Cu multilayered composite has been produced by accumulati... more In this study, ultrafine grained Al5052/Cu multilayered composite has been produced by accumulative roll bonding (ARB) and fracture properties have been studied using plane stress fracture toughness. The fracture toughness has been investigated for the unprocessed specimens, primary sandwich and first, second, and third cycles of ARB process by ASTM E561 and compact tension (CT) specimens. Also, the microstructure and mechanical properties have been investigated using optical microscopy, scanning electron microscopy, uniaxial tensile tests, and microhardness measurements. The value of plane stress fracture toughness for the ultrafine grained Al5052/Cu composite increased by increasing the number of ARB cycles, continuously from the primary sandwich to end of the third cycle. The maximum value of 59.1 MPa m1/2 has been obtained that it is about 2.77 and 4.05 more than Al5052 and pure Cu (unprocessed specimens). This phenomenon indicated that ARB process and the addition of copper to ...

Predicting 3D printed plastic part properties: A deep learning approach with thermographic and vibration data fusion

Expert Systems with Applications, 2024

Additive Manufacturing (AM) holds transformative potential for the manufacturing industry, yet it... more Additive Manufacturing (AM) holds transformative potential for the manufacturing industry, yet its widespread adoption is hindered by inconsistent product properties. This study addresses this challenge by pioneering a novel predictive method to assess the impact of in-process sensing on part property prediction in Fused Deposition Modeling (FDM), serving as a representative case study. Focused on five critical mechanical properties, including surface roughness, tensile strength, elongation at break, micro-hardness, and warpage, we systematically explore various sensor combinations by integrating Inertial Measurement Unit (IMU) sensors and a thermal camera with machine setting parameters. Utilizing deep learning models, specifically hybrid Convolutional Neural Network and Long Short-Term Memory (CNN-LSTM) architectures, we encode time-series sensor data into signal images and evaluate performance across different sensor configurations. Our best-performing model achieves an impressive 99% correlation in predicting tensile strength, albeit with less robust performance in predicting warpage and micro-hardness, suggesting additional influencing factors. Furthermore, the employed signal imaging technique outperforms a handcrafted feature selection alternative. These findings carry significant implications for advancing the broader adoption of AM in critical applications, addressing challenges associated with inconsistent product properties and unlocking its full potential.

Numerical and experimental study of three-layered Al 1050/Mg AZ31B/ Al 1050 sheets formability considering strain and stress conditions through single point incremental forming

Materials Today Communications, 2024

This article examines the formability of 3-layer Al 1050/Mg-AZ31B /Al 1050 sheets experimentally ... more This article examines the formability of 3-layer Al 1050/Mg-AZ31B /Al 1050 sheets experimentally and numerically. Mg AZ31B, with its high strength-to-weight ratio, and Al 1050, with its formability and lightweight, are attractive industrial metals. In the experimental method, the forming limit diagram (FLD), the Forming limit angle (FLA), and the fracture depth were investigated for the 3-layer and base samples with two pyramid and cone geometries. The results showed that the ductility in the cone geometry is higher than that of the pyramid. Also, by comparing the FLD of the 3-layer sample to the base sample, the results showed that the formability of the 3-layer sample increased compared to the Mg-AZ31B base sample. In contrast, the formability decreased compared to the base sample of Al 1050. Numerical studies for predicting the FLD using the SPIF method were carried out using Abaqus software. The numerical techniques considered the second deviation minor strain (SDMIS), second deviation effect strain (SDEF), second deviation thickness (SDT), and second deviation major strain (SDMS). The results showed that the highest accuracy occurred for the SDT method compared to other numerical methods. To remove the effect of the strain path on the numerical analysis for predicting the FLD (from the stress analysis method), a second deviation of von Mises stress (SDVMS) was used. By examining the results, it was found that the results of numerical methods considering stress could be highly accurate.
Graphical Abstract

Multipoint forming process of aluminum sheet considering its forming limit diagram: Experimental and numerical investigations

Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications, 2024

Considering the significance of sheet metal forming in various industries, metal sheets, and ligh... more Considering the significance of sheet metal forming in various industries, metal sheets, and lightweight alloys find extensive applications. It is essential to predict the formability limit of sheets. Whereas the previous studies used the Nakazima test, this study aims to determine the forming limit diagram (FLD) numerically and experimentally using multipoint forming, considering the strain path's effect on formability. Also, it is compared with the conventional FLD obtained via the Nakazima test. The results show that multipoint forming improves sheet metal forming. The experimental FLD for an AL 2024-O sheet with a 12 mm pin size was found to have higher formability than that obtained from the Nakazima test. The effect of the polyurethane layer on the forming limit diagram was investigated. The experimental results showed that the polyurethane layer prevents local strain and increases the limits on the forming limit diagram. The numerical forming limit diagram was predicted by the second derivative method. Finally, the experimental results were compared with the numerical simulation results, showing that the results had an agreement above 90%. This method can be used as a reference for assessing the effectiveness of the multipoint forming technique.

Microstructure investigation and optimization of process parameters of ultrasonic welding for Al–Cu dissimilar joints using design of experiment

Journal of Materials Research and Technology, 2024

Ultrasonic Metal Welding (UMW) employs high-power ultrasonic vibrations to join thin metal sheets... more Ultrasonic Metal Welding (UMW) employs high-power ultrasonic vibrations to join thin metal sheets of different materials, effectively addressing the thermal damage issues associated with traditional welding methods. This study aimed to optimize the joining of thin aluminum (Al) and pure copper (Cu) metal sheets using high-power ultrasonic vibration. The investigation focused on the effect of input parameters, including time, static pressure, and welding power, on the output parameter of joint strength. The results indicated that the welding time had the most significant effect on the load obtained from the Tensile-shear test. The optimal condition was determined to be a welding time of 0.98 s, a pressure of 2 bar, and a power of 85%, resulting in a maximum predicted tensile-shear test load of 753.3 N, with an error value of 11.4% obtained from the software. Microscopic images reveal that the welding mechanism in ultrasonic welding involves continuous plastic deformation, dispersion of oxide layers, and the formation and extension of micro-bonds along the weld line.

Investigation and optimization on the formability of aluminum 1050/ stainless steel 304L bilayer sheets fabricated by cold roll bonding considering the Box-Behnken method

Journal of Materials Research and Technology, 2024

Composite metal sheets have found extensive applications thanks to their high corrosion and wear ... more Composite metal sheets have found extensive applications thanks to their high corrosion and wear resistance, as well as greater strength, stiffness, and formability relative to the base sheets. Stainless steel composite sheets account for over 80% of the metallic composite sheets. Their higher performance and lower costs have increased their applications in the food and automotive industries. This study experimentally addressed the formability of the Al 1050/Stainless Steel 304 L bilayer sheets prepared through the cold rolling process. After designing the experiment using the response surface method, considering the layer thickness and reduction ratio of the rolling process, the bilayer sheets were prepared using the cold roll bonding process. Formability included the forming limit diagram, the magnitude of FLD 0 , and elongation, which were derived by Nakazima and tensile tests. Then, the formability was optimized as a function of input parameters considering the Box-Behnken method. To this end, a new criterion was presented to compare the formability of the sheets. This criterion can be used to assess the formability of a sheet considering various loading modes. Microstructural observations justified the variations in the formability of the bilayer sheets against the input parameters, i.e., thickness ratio and reduction ratio. The results indicated that the formability of the Al 1050/Stainless Steel 304 L bilayer sheet (i.e., safe forming region) reached its maximum value at t Al = 4mm; t SS = 0.8mm; and r = 45%.

Novel hybrid 3D-printed auxetic vascular stent based on reentrant and meta-trichiral unit cells: finite element simulation with experimental verifications

materials today communications, 2023

In this study, a novel re-entrant meta-trichiral auxetic (RMCA) vascular stent with improved mech... more In this study, a novel re-entrant meta-trichiral auxetic (RMCA) vascular stent with improved mechanical properties was designed by combining three auxetic unit cells: re-entrant, trichiral, and anti-trichiral. The in-plane tensile behavior of RMCA structure was investigated through finite element analysis and experimental tests were performed to verify the finite element analysis (FEA) results. 3D printing was employed to fabricate the samples. The effect of various geometric parameters on the in-plane behavior of RMCA structure, including the stress-strain curve and Poisson's ratio, were studied using FE analysis. The highest value of negative Poisson's ratio obtained for RMCA structure was equal to-4.91, which is a stunning value among auxetic structures. After that the vascular stent was proposed using the most appropriate structure determined by the parametric investigation. Finite element analysis (FEA) was conducted to evaluate the behavior of the stent during the deployment process (angioplasty), and interaction between the vascular stent, artery, and plaque. The dogboning, foreshortening, and recoil of the vascular stent were evaluated using the FEA results. Also, bending flexibility of the vascular stent was investigated based on FEA and three-point bending tests.

Novel hybrid 3D-printed auxetic vascular stent based on re-entrant and meta-trichiral unit cells: Finite element simulation with experimental verifications

Materials Today Communications, 2023

In this study, a novel re-entrant meta-trichiral auxetic (RMCA) vascular stent with improved mech... more In this study, a novel re-entrant meta-trichiral auxetic (RMCA) vascular stent with improved mechanical properties was designed by combining three auxetic unit cells: re-entrant, trichiral, and anti-trichiral. The in-plane tensile behavior of RMCA structure was investigated through finite element analysis and experimental tests were performed to verify the finite element analysis (FEA) results. 3D printing was employed to fabricate the samples. The effect of various geometric parameters on the in-plane behavior of RMCA structure, including the stress-strain curve and Poisson's ratio, were studied using FE analysis. The highest value of negative Poisson's ratio obtained for RMCA structure was equal to-4.91, which is a stunning value among auxetic structures. After that the vascular stent was proposed using the most appropriate structure determined by the parametric investigation. Finite element analysis (FEA) was conducted to evaluate the behavior of the stent during the deployment process (angioplasty), and interaction between the vascular stent, artery, and plaque. The dogboning, foreshortening, and recoil of the vascular stent were evaluated using the FEA results. Also, bending flexibility of the vascular stent was investigated based on FEA and three-point bending tests.

Optimizing FDM Process Parameters: Predictive Insights through Taguchi, Regression, and Neural Networks

Physica Scripta, 2024

Fused deposition modelling (FDM) is a popular additive manufacturing process used for rapid proto... more Fused deposition modelling (FDM) is a popular additive manufacturing process used for rapid prototyping and the production of complex geometries. Despite its popularity, FDM's susceptibility to variations in numerous process parameters can significantly impact the quality, design, functionality, and mechanical properties of 3D printed parts. This study explores thirteen FDM process parameters and their influence on the mechanical properties of polylactic acid (PLA) polymer, encompassing surface roughness, warpage, tensile and bending strength, elongation at break, deformation, and microhardness. The optimum parameters were identified alongside key contributors by applying the Taguchi method, signal-to-noise ratios, and analysis of variances (ANOVA). Notably, specific FDM parameters significantly affect the surface profile, with layer thickness contributing 32.65% and fan speed contributing 8.59% to the observed variations. Similarly, warping values show notable influence from nozzle temperature (29.53%), wall thickness (16.74%), layer thickness (16.56%), and retraction distance (12.80%). Tensile strength is primarily determined by wall thickness (31.83%), followed by infill percentage (26.73%) and infill pattern (16.18%). Elongation at break predominantly correlates with wall thickness (44.82%), with a supplementary contribution from nozzle temperature (10.90%). Microhardness lacks a dominant parameter. Bending strength variations primarily arise from layer thickness (38%), wall thickness (37.6%), and infill percentage (9.17%). Deformation tendencies are influenced by layer thickness (19.20%), print speed (11.37%), wall thickness, and fan speed (10.9% each). The optimized dataset of FDM process parameters was then employed in two prediction models: multiple-regression and artificial neural network (ANN). Evaluation based on the correlation coefficient (R 2) and root mean squared error (RMSE) indicates that the ANN model outperforms the multiple-regression approach. The results indicate that precise control of FDM parameters, coupled with ANN predictions, facilitates the fabrication of 3D printed parts with the desired mechanical characteristics.

Study of single point incremental forming limits of Al 1050/Mg-AZ31B two-layer sheets fabricated by roll bonding technique: Finite element simulation and experiment

by Ramin Hashemi and Ramin Hashemi

Journal of Materials Research and Technology, 2024

In this work, for the first time, the two-layer Aluminum (Al 1050) and magnesium (AZ31B) sheet we... more In this work, for the first time, the two-layer Aluminum (Al 1050) and magnesium (AZ31B) sheet were used in the single point incremental forming (SPIF) process. Due to the high strength-to-weight ratio of the Al 1050/Mg-AZ31B sample, today it is used in significant industries such as automotive and aerospace. The finite element simulation process was carried out using the Abaqus Software considering five approaches to determine forming limits. These approaches were forming limit diagram criterion (FLDcrt), effective strain rate (ESR), second derivation of thinning (SDT), Major strain rate (MSR) and Thickness strain rate (TSR) methods. The results showed that the failure prediction in the FLDcrt method was more accurate than other methods. The thickness distribution process was carried out both by simulation and experiment to validate the simulation results. The results show a good agreement between simulation and experimental results. Finally, the results obtained from the SPIF process were compared with the FLD results of the conventional hemispherical punch test, and it was observed that the FLD was higher in the SPIF process. Moreover, the layer arrangement, which affects formability, was investigated. The results showed that the FLD with Mg-AZ31B/Al 1050 arrangement fails in higher strains compared to Al 1050/Mg-AZ31B. After validating the simulation results, the parameter effect of the stepdown and tool diameter on the two-layer formability was investigated by the design of experiment. Considering the greater importance of the step-down and tool diameter effect on the created stresses and forming time compared to other parameters, their effect will be investigated. The results showed an optimal condition for the tool diameter, but an opposite relationship with formability was obtained for the step-down.

$Research paper thumbnail of The role of applied strain and volume percentage of components on mechanical properties and fracture toughness in multilayered Al/Mg composite fabricated by the accumulative roll bonding process$

The role of applied strain and volume percentage of components on mechanical properties and fracture toughness in multilayered Al/Mg composite fabricated by the accumulative roll bonding process

Materials Research Express, 2021

In this study, for the first time, the effect of applied strains and volume percentage of compone... more In this study, for the first time, the effect of applied strains and volume percentage of components of layered composite on the mechanical properties and fracture toughness of Al/Mg were investigated experimentally. The multilayered Al/Mg were produced by the accumulative roll bonding (ARB) process. For the investigation, three Al/Mg composites with different volume percentages (25%, 50%, and 66.6%Al) at different applied strains (0.8–3.2) were produced. The experimental evaluation included microscopic examination by optical microscope imaging, uniaxial tensile test, and plane strain fracture toughness. As the applied strain for all three composites increased, plastic instability in the magnesium reinforcement intensified, but due to the low thickness of the Al layers compared to the Mg layer, uniform structure of Mg distribution in Al for all three composite was not achieved. Also, by adding Al layers to the primary composite, a lower shear strain was applied to the magnesium rein...

Fabrication of AA1050/CP-Cu Bimetallic Tubes using Parallel Tube-Shaped Channel Angular Pressing Technique and Assessing its Mechanical Properties and Microstructure

Transactions of the Indian Institute of Metals

Nowadays, the need to use multi-layered materials in various industries due to their unique prope... more Nowadays, the need to use multi-layered materials in various industries due to their unique properties, such as resistance to wear, corrosion, and weight lightening, is augmenting. In this paper, the production of bimetallic aluminum (AA 1050) /commercially pure Cu tubes by cold parallel tube-shaped channel angular pressing (PTCAP) process was considered for the first time. The PTCAP process was performed in three passes, and the bonding properties, microstructure, and microhardness were evaluated in each pass. The microstructure and mechanical properties of PTCAPed samples were examined by Optical microscopy (OM), scanning electron microscope (SEM), Energy Dispersive X-ray Spectroscopy (EDS), Vickers microhardness test, and shear punch test. According to the results, the Cu and Al PTCAPed tubes&#39; microhardness was improved by 125% and 87%, respectively. Besides, after three passes, the mean size of grains of the copper tube decreased from 58 to 6μm. Therefore, based on the Hall-Petch relationship, the main reason for the increase in microhardness can be stated as the significant reduction in grain size. According to the shear punch test results, after three passes of PTCAP, the shear strength between the two layers was increased by 208%. Finally, both tubes were well bonded as a bilayer tubes at higher passes.

Analytical and numerical investigation of Bulge test in bimetallic sheets

Application of an Extended Strain-Based Forming Limit Curve in Finite Element Simulation of X-Branch Hydroforming

This work presents a numerical framework that implements extended forming limit curves (FLCs) to ... more This work presents a numerical framework that implements extended forming limit curves (FLCs) to predict bursting during tube hydroforming process. Here, at first, the extended FLC is calculated for tube material based on the generalized M-K model that takes the through thickness normal stress into account. As a case study, the forming process of X-shaped branch is simulated by ABAQUS/EXPLICIT commercial finite element package. The required incremental plastic equivalent strain and strain ratio, which are required for comparison with the computed extended FLC, are extracted from the results of FE simulation. The robustness of the extended FLC in prediction of necking is tested by comparing with the published experimental data where a satisfactory agreement is found.

Printing strategies to fabricate a disk through the fused deposition modelling method

Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications, 2023

The Fused Deposition Modelling (FDM) technique is widely used in different industries due to its ... more The Fused Deposition Modelling (FDM) technique is widely used in different industries due to its low cost and ability to produce complex geometries from polymers. In this technique, some manufacturing parameters are essential because of their effects on the mechanical performance of the final fabricated part. The current study investigated the impact of path strategy and printing speed, two key manufacturing factors, on the mechanical performance of printed disks. Six types of path strategies of rasters corresponding to the loading direction, namely unidirectional-vertical, unidirectional-horizontal, unidirectional-45, cross, cross-45, and concentrate, were used for printing some disks, and compressive tests were done on them. The results showed that these path strategies' average compressive failure loads were 2955, 4957, 2342, 4640, 3971, and 5893 N, respectively. The lower compressive strength of the unidirectional path pattern was due to the weak zones that were located between the printed layers and rasters. Besides, three printing speeds of 40, 60, and 80 mm/s were considered to fabricate the disks with a concentrate path pattern, and compressive experiments were performed. The results showed that the 40 mm/s printing speed conducted a compressive failure load of 4544 N, while 60 and 80 mm/s resulted in 3008 and 2828 N, respectively. Finally, inter-layer strength as a major factor in controlling the compressive strength of the disks was comprehensively discussed.

Experimental investigation of parameters in fused filament fabrication -3D printing process of ABS plus using response surface methodology

The International Journal of Advanced Manufacturing Technology, 2023

3D printing by Fused Filament Fabrication (FFF) can produce complicated products often used for p... more 3D printing by Fused Filament Fabrication (FFF) can produce complicated products often used for prototyping. The major challenge for this technology is the production of functional parts with suitable mechanical properties. It is possible to improve the mechanical properties of the parts produced with FFF by correctly selecting and combining the process parameters. In this research, acrylonitrile butadiene styrene plus (ABS plus) samples with three variable parameters, including infill density, layer thickness, and raster angle, were printed to evaluate the ultimate tensile strength (UTS) and fracture strain in the tensile test. The two-dimensional digital image correlation (2D-DIC) technique measured the full-field surface strain. Before starting the test, the appropriate contrast of the sample surface was ensured using a histogram. The results were validated and predicted using response surface methodology (RSM). Prediction of the results using the quadratic model reveals that the mean error obtained for UTS and fracture strain was 2.96% and 2.87%, respectively. The analysis of variance (ANOVA) was used to validate the model. Also, the effect of the individual and interaction parameters on the response was examined. The raster angle parameter, directly related to transferring the load to the sample, was recognized as the most crucial parameter affecting both responses. The optimization results to maximize UTS and fracture strain values indicate 73.42% infill density, 0.227 mm layer thickness, and zero-degree raster angle, leading to UTS of 34.92 MPa and fracture strain of 3.59%. Finally, the field emission scanning electron microscope (FESEM) is employed to investigate the failure mechanism in the samples.

Review of selective laser melting of magnesium alloys: advantages, microstructure and mechanical characterizations, defects, challenges, and applications

Journal of Materials Research and Technology

parameters. The characterization of the primary powder is divided into two categories: morphology... more parameters. The characterization of the primary powder is divided into two categories: morphology and particle size, along with chemical composition. Morphology and chemical composition play an essential role in the final part by affecting the alloy&#39;s flowability, oxidation, and ignition. Characterization of properties is also reviewed in three general densifications, mechanical properties, and microstructure of SLMed samples and their dependence on parameters and input materials. Finally, the defects and challenges are briefly discussed, and the applications of Mg alloys in two widely used areas, including automotive and medicine, are presented.

An experimental investigation of mechanical properties, forming limit curves, and bending behavior of aluminum-polymer sandwich composites

Materials Research Express, 2021

This study aimed to investigate the forming limit diagrams (FLDs), mechanical properties, and ben... more This study aimed to investigate the forming limit diagrams (FLDs), mechanical properties, and bending behavior of the three kinds of sandwich composites. The core layer in all sandwich sheets consisted of polyethylene, and just the skin layers were chosen to be AA5754 or AA3105. The results showed that the sandwich sheets are an appropriate choice to be used instead of the monometallic sheets. According to the 3-point bending test results, the flexural strength of the AL 3105/Polyethylene/AL 3105 sandwich composite is about 30 percent less than the AA3105 monometallic layer. Also, the formability of the metallic sandwich composites with non-identical skin layers was studied. The results demonstrated that using one layer AA 3105 and one layer AA5754 instead of AA5754 for both skin layers, although formability decreased about 11% in the plane strain region, the cost of fabricating the composite was decreased sheet reduces almost 75%. As a result, using skin layers with the different g...

Formability of Tri-layered IF240/AZ31/IF240 Composite with Strong Bonding: Experimental and Finite Element Modeling

Journal of Materials Engineering and Performance, 2021

In this work, the formability of a hybrid material of Interstitial-Free 240 (IF240) steel and AZ3... more In this work, the formability of a hybrid material of Interstitial-Free 240 (IF240) steel and AZ31 magnesium alloy as IF240/AZ31/IF240 tri-layered sheets was investigated. For this purpose, the bonding feasibility of the high-formability IF240 steel and low-formability AZ31 sheets was first assessed. Then, the hot formability behavior of the manufactured laminated composite was evaluated. The rolling of the preheated samples established the layer bonding. The bonding strength was determined using the shear punch test. The texture and its effects on the forming behavior were studied using the x-ray Goniometry method. Nakazima dome tests were employed at ambient and elevated temperatures to determine formability and forming limit curves. The forming process simulation was performed by ABAQUS/Explicit solver, and the results were compared with the experimental data. The results showed that post-annealing time and thickness reduction have significant impacts on the bond strength. The formability of the composite laminate improved significantly by an increase in the temperature. Simulation results of the composite forming behavior were in fair agreement with the experimental results.

Finite element simulations and experimental verifications for forming limit curve determination of two-layer aluminum/brass sheets considering the incremental forming process

Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications, 2021

In this paper, forming limit diagram (FLD) of aluminum/brass two-layer sheets through an incremen... more In this paper, forming limit diagram (FLD) of aluminum/brass two-layer sheets through an incremental forming process (ISF) was studied numerically and experimentally. At first, the two-layer aluminum 1050/brass (65% copper) sheets were fabricated using the roll bonding process. Also, the finite element simulations of the incremental forming process with ABAQUS software were utilized to predict the FLD. For this purpose, the criterion of the second derivative of the equivalent plastic strain was used to predict fracture. Finally, the numerical simulation results were compared with the experimental results. For instance, comparing experimental and numerical FLD0 values for the formed samples with forming angle 62.5-degree showed a 7% difference. However, the difference was negligible, and numerical simulation results could be used with an appropriate reliability coefficient. The effect of sheet arrangement towards tools was then investigated. It finds out from the experimental results...

An Experimental Study of Fracture Toughness for Nano/Ultrafine Grained Al5052/Cu Multilayered Composite Processed by Accumulative Roll Bonding

Journal of Manufacturing Science and Engineering, 2018

In this study, ultrafine grained Al5052/Cu multilayered composite has been produced by accumulati... more In this study, ultrafine grained Al5052/Cu multilayered composite has been produced by accumulative roll bonding (ARB) and fracture properties have been studied using plane stress fracture toughness. The fracture toughness has been investigated for the unprocessed specimens, primary sandwich and first, second, and third cycles of ARB process by ASTM E561 and compact tension (CT) specimens. Also, the microstructure and mechanical properties have been investigated using optical microscopy, scanning electron microscopy, uniaxial tensile tests, and microhardness measurements. The value of plane stress fracture toughness for the ultrafine grained Al5052/Cu composite increased by increasing the number of ARB cycles, continuously from the primary sandwich to end of the third cycle. The maximum value of 59.1 MPa m1/2 has been obtained that it is about 2.77 and 4.05 more than Al5052 and pure Cu (unprocessed specimens). This phenomenon indicated that ARB process and the addition of copper to ...