Computational Mechanics

The purpose is to propose an improved method for inverse boundary value problems. This method is presented on a model problem. It introduces a higher order problem. BEM numerical simulations highlight the efficiency, the improved accuracy, the robustness to noisy data of this new approach, as well as its ability to deblur noisy data. Keywords Cauchy problem • inverse problem • boundary values • boundary element method • regularization

This paper presents the general purpose framework Peano for the solution of partial differential equations (PDE) on adaptive Cartesian grids. The strict structuredness and inherent multilevel property of these grids allows for very low memory requirements, efficient (in terms of hardware performance) implementations of parallel multigrid solvers on dynamically adaptive grids, and arbitrary spatial dimensions. This combination of advantages distinguishes Peano from other PDE frameworks. We describe shortly the underlying octree-like grid type and its most important properties. The main part of the paper shows the framework concept of Peano and the implementation of a Navier-Stokes solver as one of the main currently implemented application examples. Various results ranging from hardware and numerical performance to concrete application scenarios close the contribution.

A numerical methodology is presented for the modeling of convection-diffusion controlled mushy region change problems. An ef®cient and accurate non-staggered control volume method, based on the momentum interpolation practice and on a high-order convection differencing scheme, is proposed for the solution of the continuum model equation. Suitable numerical techniques are implemented to overcome the numerical instability problems resulting from the strong coupling between the equations of the model. Special attention is given on the ef®cient treatment of the latent head evolution in the energy equation. A new numerical technique is developed which accounts for the dependence of the latent heat on the variation of temperature and concentration ®elds. The proposed method is applied on two phase change problems. Satisfactory agreement with previously published results is observed.

Attention is here focused on the implementation of a coupled BEM–FEM procedure employing the BE method for the modelling of the near-crack region and the FEM for the far-field, where no singularities in the stress field are expected to arise. The symmetric variational version of the BE method is utilized, allowing to obtain a final linear system endowed with a symmetric matrix. With respect to 3D linear elastic fracture mechanics, the code developed is used to evaluate stress intensity factors for some benchmarks and simulate fracture propagation.

A dislocation density-based crystalline plasticity formulation, specialized finite-element techniques, and rational crystallographic orientation relations were used to predict and characterize the failure modes associated with the high strain rate behavior of aluminum layered composites. Two alloy layers, a high strength alloy, aluminum 2195, and an aluminum alloy 2139, with high toughness, were modeled with representative microstructures that included precipitates, dispersed particles, and different grain boundary distributions. Different layer arrangements were investigated for high strain rate applications and the optimal arrangement was with the high toughness 2139 layer on the bottom, which provided extensive shear strain localization, and the high strength 2195 layer on the top for high strength resistance The layer thickness of the bottom high toughness layer also affected the bending behavior of the roll-bonded interface and the potential delamination of the layers. Shear strain localization, dynamic cracking, and delamination are the mutually competing failure mechanisms for the layered metallic composite, and control of these failure modes can be used to optimize behavior for high strain rate applications.

A social network is a graph where people or organizations (depending on the application) are represented as nodes connected by edges that can refer to either tight social bonds or some common, shared aspect. The graph structure analysis and the statistical analysis of specific node/edge attributes can reveal important individuals, relationships, and clusters. New information continues to be collected and stored, and size and complexity of the semantic graphs overwhelm the human cognitive abilities. Hence, it is necessary to improve the computational mechanisms to analyze such volume of data. In this paper, we focus on analyzing the information from social networks, extracting relevant knowledge, and visualizing the facts resultant from the analysis.

An adhesively laminated element taking into consideration peel stress is developed for a piezoelectric smart plate. In this novel finite element analysis formulation, a four node piezoelectric element is firstly derived, and an adhesive element of finite thickness with both shear and peel stiffness is sandwiched between two collocated four node plate elements to form an adhesively laminated element for a piezoelectric smart plate. In this framework of finite element analysis, because the displacement filed in this adhesively laminated element is continuous and a plate element is derived based on the Reissner-Mindlin plate theory, and thus it can be accurately applied to a thin or moderately thick host plate with bonded or debonded piezoelectric actuators and sensors. The formulation is performed for an isotropic host plate and a fiber reinforced laminate plate. Numerical results are presented to compare with those of the exact solutions for smart beams, and validate with the experimental results of the isotropic and composite host plates available in the literature. Using the present finite element analysis formulation, energy transfer stresses in the adhesive and equivalent forces induced in the host plate are investigated. The present formulation is demonstrated to allow debondings of piezoelectric patches and the debonding detection.

On the basis of continuum mechanics, a rate dependent directional damage model for fibred materials with application to soft biological tissues is presented. The structural model is formulated using the concept of internal variables that provides a very general description of materials involving irreversible effects. Continuum damage mechanics is used to describe the softening behavior of soft tissues under large deformation. To account for the rate dependency and to regularize the localization problems associated with strain-softening, a viscous damage mechanism is presented in this paper in decoupled form for matrix and fibers. The numerical implementation in the context of the finite element method is discussed in detail. In order to show the performance of the constitutive model and its algorithmic counterpart some simple examples are included. Results show that the model is able to capture the typical stress–strain behavior observed in fibrous soft tissues and appear to confirm the soundness of the proposed formulation.

We use the meshless local Bubnov–Galerkin (MLPG6) formulation to analyze free and forced vibrations of a segmented bar. Three different techniques are employed to satisfy the continuity of the axial stress at the interface between two materials: Lagrange multipliers, jump functions, and modified moving least square basis functions with discontinuous derivatives. The essential boundary conditions are satisfied in all cases by the method of Lagrange multipliers. The related mixed semidiscrete formulations are shown to be stable, ...

The turning of hardened steels has been applied in many cases in production. It is an important process because all manufacturers are continu¬ally seeking ways to manufacture their parts with lower cost, higher quality, rapid setups, lower investment, and smaller tooling inventory while eliminating non-value added activities. Currently, the most important problem is concerned with the properties of the surface finish. This paper investigates the effect on surface finish and tool wear in a continuous dry turning of hardened steel when using a ceramic wiper tools. This report describes about the hard turning of AISI 4340 alloy steel by varying various parameters. The hard turning parameters are: Cutting speed, Feed and Depth of cut. The main objectives of this project, study the effect of parameters such as cutting speed, feed, depth of cut on surface roughness, tool wear and cutting force during the hard turning of AISI 4340alloy steel using ceramic wiper tool and the effect of various process parameters on hard tuning and optimize the cutting parameters. The dry turning experiments were performed on hardened AISI 4340 steel material using ceramic wiper tool .AISI 4340 steel having hardness: 48 (48–52) HRC was used.

Keywords— Hard turning, surface roughness, taguchi’s method.

 A differential quadrature element method (DQEM) based on first order shear deformation theory is developed for free vibration analysis of non-uniform beams on elastic foundations. By decomposing the system into a series of sub-domains or elements, any discontinuity in loading, geometry, material properties, and even elastic foundations can be considered conveniently. Using this method, the vibration analysis of general beam-like structures is to be studied. The governing equations of each element, natural compatibility conditions at the interface of two adjacent elements and the external boundary conditions are developed in a systematic manner, using Hamilton's principle. The present DQEM is to be implemented to Timoshenko beams resting on partially supported elastic foundations with various types of boundary conditions under the action of axial loading. The general versality, accuracy, and efficiency of the presented DQEM are demonstrated having solved different examples and compared to the exact or other numerical procedure solutions.

This paper briefly describes the risks of floods caused by torrential rains and possible flooding of the City by demolishment of the dam "Matka". It describes the procedures and measures for the protection and safety during flooding of a specific area. The focus in this paper is given to the visualization (mapping) of possible flood by using the program Quantum GIS, as a powerful tool for managing the risks of catastrophic flooding and making quick and accurate decisions to undertake appropriate measures to prevent it. The possibilities offered by the program to display the possible flood and to analyse of all data obtained with it are given.

Using the Stochastic Finite Element Method (SFEM) to perform reliability analysis of the free vibration of composite plates with material and fabrication uncertainties has received much attention lately. In this work the stochastic analysis is performed using the First-Order Reliability Method (FORM-method 2) and the Second-Order Reliability Method (SORM). The basic random variables include laminae stiffness properties and material density, as well as the randomness in ply orientation angles. Modeling of the composite behavior utilizes a nine-noded isoparametric Lagrangian element based on the third-order shear deformation theory. Calculating the eigenvectors at the mean values of the variables proves to be a reasonable simplification which significantly increases solution speed. The stochastic finite element code is validated using comparisons with results of Monte Carlo simulation technique with importance sampling. Results show that SORM is an excellent rapid tool in the stochastic analysis of free vibration of composite plates, when compared to the slower Monte Carlo simulation techniques.

A cell vertex finite volume method for the solution of steady compressible turbulent flow problems on unstructured hybrid meshes of tetrahedra, prisms, pyramids and hexahedra is described. These hybrid meshes are constructed by firstly discretising the computational domain using tetrahedral elements and then by merging certain tetrahedra. A one equation turbulence model is employed and the solution of the steady flow equations is obtained by explicit relaxation. The solution process is accelerated by the addition of a multigrid method, in which the coarse meshes are generated by agglomeration, and by parallelisation. The approach is shown to be effective for the simulation of a number of 3D flows of current practical interest.

In recent years adaptive stabilized finite element methods, here referred to as General Galerkin (G2) methods, have been developed as a general methodology for the computation of mean value output in turbulent flow. In earlier work, in the setting of bluff body flow, the use of no slip boundary conditions has been shown to accurately capture the separation from a laminar boundary layer, in a number of benchmark problems. In this paper we extend the G2 method to problems with turbulent boundary layers, by including a simple wall-model in the form of a friction boundary condition, to account for the skin friction of the unresolved turbulent boundary layer. In particular, we use G2 to simulate drag crisis for a circular cylinder, by adjusting the friction parameter to match experimental results. By letting the Reynolds number go to infinity and the skin friction go to zero, we get a G2 method for the Euler equations with slip boundary conditions, which we here refer to as an EG2 method. The only parameter in the EG2 method is the discretization parameter, and we present computational results indicating that EG2 may be used to model very high Reynolds numbers flow, such as geophysical flow.

This paper is concerned with the variationally consistent incorporation of time dependent boundary conditions. The proposed methodology avoids ad hoc procedures and is applicable to both linear as well as nonlinear problems. An integral formulation of the dynamic problem serves as a basis for the imposition of the corresponding constraints, which are enforced via the consistent form of the penalty method, e.g. a form that complies with the norm and inner product of the functional space where the weak formulation is posed. Also, it is shown that well known and broadly implemented modelling techniques such as "large mass" and "large spring" methods, arise as limiting cases of the penalty formulation. Further extension of the proposed methodology is provided in the case where a generalized weak formulation of the dynamic problem with an independent velocity field is assumed. Finally, a few examples serve to illustrate the above concepts.

The solution of the problem of frictional interaction between a rope and a rigid cylinder is known since many years as Euler-Eytelwein problem or belt friction problem and is solved as a 2D problem describing the interaction between a rope and a circle. Here we generalize the solution under a first assumption that the rope is formed as a spiral line on a rigid cylinder. Various frictional cases are considered. The classical 2D result can be directly recovered. The path for further solutions with different geometries is then open.

Currently, the gantry crane in LAPAN Garut still uses steel material. The steel material is protected using a coating to minimize the impact of corrosion. However, this method is less efficient, considering the corrosion rate in LAPAN Garut is very high because it is located on the coast of Cilauteureun. It also creates problems in terms of maintenance because it has to be done regularly and periodically repainting. In addition, not all equipment is available maintenance funds every year. The objective of this paper is to design and analyze the stress of a gantry crane with a capacity of 9 tons using Aluminum 6061 material. The material used is three units of JIS G 3192 H standard frame (I-shape) with a size of 150 x 150 x 7 mm, four units of JIS G 3466 frame (square profile) with a size of 150 x 150 x 6 mm, and four units of JIS G 3466 frame (square profile) with a size of 125 x 125 x 6 mm. Finite element analysis is performed using Autodesk Inventor Professional 2017 software. The simulation results show that the gantry crane has a mass, von Mises stress, deformation, and safety factors respectively at 165.36 kg; 132.9 MPa; 13.67 mm; and 2.07.

Im Laufe der letzten zehn Jahre sind in Zusammenarbeit zwischen Schwab Verkehrstechnik AG in Schaffhausen und der Züricher Hochschule Winterthur hydraulische Stoss-und Zugvorrichtungen für Güter-und Personenzüge entwickelt worden. Dank den Simulationsmodellen konnte die Zahl der Prototypen sehr klein gehalten werden. In den ersten Jahren ist das systemdynamische Werkzeug STELLA, danach Matlab/Simulink und zuletzt Modelica eingesetzt worden. Trotz Umfang und Erfolg dieses Unternehmens handelt es sich eigentlich um ein " Abfallprodukt " didaktischer Bemühungen, der Entwicklung der Physik der dynamischen Systeme.

The loading of a granular material induces anisotropies of the particle arrangement (fabric) and of the material’s strength, incremental stiffness, and permeability. Thirteen measures of fabric anisotropy are developed, which are arranged in four categories: as preferred orientations of the particle bodies, the particle surfaces, the contact normals, and the void space. Anisotropy of the voids is described through image analysis and with Minkowski tensors. The thirteen measures of anisotropy change during loading, as determined with three-dimensional discrete element simulations of biaxial plane strain compression with constant mean stress. Assemblies with four different particle shapes were simulated. The measures of contact orientation are the most responsive to loading, and they change greatly at small strains, whereas the other measures lag the loading process and continue to change beyond the state of peak stress and even after the deviatoric stress has nearly reached a steady state. The paper implements a methodology for characterizing the incremental stiffness of a granular assembly during biaxial loading, with orthotropic loading increments that preserve the principal axes of the fabric and stiffness tensors. The linear part of the hypoplastic tangential stiffness is monitored with oedometric loading increments. This stiffness increases in the direction of the initial compressive loading but decreases in the direction of extension. Anisotropy of this stiffness is closely correlated with a particular measure of the contact fabric. Permeabilities are measured in three directions with lattice Boltzmann methods at various stages of loading and for assemblies with four particle shapes. Effective permeability is negatively correlated with the directional mean free path and is positively correlated with pore width, indicating that the anisotropy of effective permeability induced by loading is produced by changes in the directional hydraulic radius.

This paper deals with the applications of stochastic spectral methods for structural topology optimization in the presence of uncertainties. A non-intrusive polynomial chaos expansion is integrated into a topology optimization algorithm to calculate low-order statistical moments of the mechanical–mathematical model response. This procedure, known as robust topology optimization, can optimize the mean of the compliance while simultaneously minimizing its standard deviation. In order to address possible variabilities in the loads applied to the mechanical system of interest, magnitude and direction of the external forces are assumed to be uncertain. In this probabilistic framework, forces are described as a random field or a set of random variables. Representation of the random objects and propagation of load uncertainties through the model are efficiently done through Karhunen–Loève and polynomial chaos expansions. We take advantage of using polygonal elements, which have been shown to be effective in suppressing checkerboard patterns and reducing mesh dependency in the solution of topology optimization problems. Accuracy and applicability of the proposed methodology are demonstrated by means of several topology optimization examples. The obtained results, which are in excellent agreement with reference solutions computed via Monte Carlo method, show that load uncertainties play an important role in optimal design of structural systems, so that they must be taken into account to ensure a reliable optimization process.

A cohesive-zone approach is used to study the interaction between an approaching crack and a particle embedded in a matrix material as a function of the mismatch in elastic and fracture properties. Crack-particle interaction is a crucial issue governing fracture behavior of particle-dispersed materials. Special attention is given in the present work to the effect of the mismatch in fracture properties, namely fracture strength and energy, which has not been fully-explored in the literature. Based on extensive finite element simulations using cohesive elements, the basic fracture mechanisms governing the crack-particle interaction are identified, namely particle fracture, crack deflection and interface debonding. The details of the cracking sequences are elucidated and the role of secondary cracks is highlighted. The effect of pre-existing flaws on the fracture behavior is analyzed both for flaws inside the particle as well as flaws on the particle/matrix interface. Several flaw configurations in terms of size, orientation and location are considered. In addition, the effect of the mismatch between the matrix and the interface fracture properties is also considered for a wide range of adhesive characteristics. The results of the simulations are summarized in the form of several fracture maps for different configurations, whereby the main fracture mechanisms are identified in regions inside a two-dimensional space of strength and toughness mismatch between the particle and the matrix. It is observed that the mismatch in the fracture properties usually plays a more dominant role on the crack trajectory than the mismatch in elastic properties in a particle-dispersed system. Pre-existing flaws/defects in the particle and the interface are found to be one of the principal controlling factors that alter the crack propagation characteristics. These results can be used as a guideline for designing particulate composite system with a preferred fracture mechanism, namely matrix cracking, interface debonding or particle fracture.

A force-based fiber beam-column element is proposed for the capacity assessment of frame structures under high shear. The proposed element is suitable for the performance assessment of large scale steel structures, which are not flexure-dominated. The element formulation follows the assumptions of the Timoshenko beam theory, while its kinematics are obtained through the natural-mode method. The element state-determination phase, instead of uniaxial material laws, typically associated with fiber elements, is based on a three-dimensional law taking into consideration the interaction between axial, bending, shear and torsion. Numerical examples are presented confirming the accuracy and the computational efficiency of the proposed formulation under monotonic, cyclic and dynamic/seismic loading. Compared to experimental results and the results of detailed finite element models, excellent agreement is achieved.

The acquisition of new skills over a life span is a remarkable human ability. This ability, however, is constrained by age of acquisition (AoA); that is, the age at which learning occurs significantly affects the outcome. This is most clearly reflected in domains such as language, music, and athletics. This article provides a perspective on the neural and computational mechanisms underlying AoA in language acquisition. The authors show how AoA modulates both monolingual lexical processing and bilingual language acquisition. They consider the conditions under which syntactic processing and semantic processing may be differentially sensitive to AoA effects in second-language acquisition. The authors conclude that AoA effects are pervasive and that the neural and computational mechanisms underlying learning and sensorimotor integration provide a general account of these effects.

1935-36, while on leave from MIT. During World War II he developed improvements in radar and Navy projectiles and devised a method of solving problems of fire control. In the years after World War II Wiener worked with the Mexican physiologist Arturo Rosenblueth on problems in biology, and formulated the set of ideas spanning several disciplines which came to be known as 'cybernetics'. He worked with engineers and medical doctors to develop devices that could replace a lost sensory mode. He analysed some non-linear mathematical problems and, with Armand Siegel, reformulated quantum theory as a stochastic process. He also became an articulate commentator on the social implications of science and technology. In 1964 Wiener was recipient of the US National Medal of Science. His published works include The Fourier Integral alld Certain oJlts

One of the successful approaches to model the time-dependent behaviour of elastomers is proposed by Bergström and Boyce (JMPS 46:931–954, 1998). The model is micromechanically inspired from the relaxation of a single entangled chain in a polymer gel matrix. Although the theory of inelasticity based on multiplicative decomposition of the deformation gradient is well established, the complexity of the nonlinear evolution law as well as the nonlinear equilibrium and non-equilibrium material response necessitates a precise description of the algorithmic setting. This contribution presents for the first time a novel numerical implementation of the Bergström–Boyce model in the context of finite element analysis and elaborates theoretical aspects of the model. The thermodynamical consistency of the evolution law is proven and a parameter study with respect to the material parameters has been carried out. The agreement of the model with the recent experimental data is investigated.

Activated neuronal groups typically engage in rhythmic synchronization in the gamma-frequency range (30–100 Hz). Experimental and modeling studies demonstrate that each gamma cycle is framed by synchronized spiking of inhibitory interneurons. Here, we review evidence suggesting that the resulting rhythmic network inhibition interacts with excitatory input to pyramidal cells such that the more excited cells fire earlier in the gamma cycle. Thus, the amplitude of excitatory drive is recoded into phase values of discharges relative to the gamma cycle. This recoding enables transmission and read out of amplitude information within a single gamma cycle without requiring rate integration. Furthermore, variation of phase relations can be exploited to facilitate or inhibit exchange of information between oscillating cell assemblies. The gamma cycle could thus serve as a fundamental computational mechanism for the implementation of a temporal coding scheme that enables fast processing and flexible routing of activity, supporting fast selection and binding of distributed responses. This review is part of the INMED/TINS special issue Physiogenic and pathogenic oscillations: the beauty and the beast, based on presentations at the annual INMED/TINS symposium (http://inmednet.com).

A meshless approach to the analysis of arbitrary Kirchhoff plates by the Element-Free Galerkin (EFG) method is presented. The method is based on moving least squares approximant. The method is meshless, which means that the discretization is independent of the geometric subdivision into "finite elements". The satisfaction of the C 1 continuity requirements are easily met by EFG since it requires only C 1 weights; therefore, it is not necessary to resort to Mindlin-Reissner theory or to devices such as discrete Kirchhoff theory. The requirements of consistency are met by the use of a quadratic polynomial basis. A subdivision similar to finite elements is used to provide a background mesh for numerical integration. The essential boundary conditions are enforced by Lagrange multipliers. It is shown, that high accuracy can be achieved for arbitrary grid geometries, for clamped and simply-supported edge conditions, and for regular and irregular grids. Numerical studies are presented which show that the optimal support is about 3.9 node spacings, and that high-order quadrature is required.

The object-oriented design and implementation of a matrix class library in C++ for parallel computing is described. The main goal of this library is to support the management of matrix data in a distributed environment and the parallel solution of linear systems of algebraic equations typical of computational mechanics applications. By using the object-oriented paradigm, a clean and consistent interface to the library is provided, and the implementation details are hidden from the user. These features improve the clarity and expressiveness of the client code and consequently ease the task of parallel programming. The library was developed and tested originally using a network of Sun Sparc 10 workstations. Test examples subsequently were run on the Intel Paragon XP/S. In these examples, the portability of the library among different distributed environments was demonstrated, and some preliminary performance studies of the library were carried out. Finally, the utilization of the class library in parallel finite-element computations is discussed. It is shown that the present library greatly simplifies the implementation of matrix operations intrinsic to parallel finite-element applications.

Preface

This book collects most of the lecture notes I have developed and I have been using in a course on Continuum Mechanics for the Master of Science Course on Computational Mechanics and the Master Course on Numerical Methods in Engineering taught at the Barcelona School of Civil Engineering, Technical University of Catalonia, UPC BarcelonaTech, in Barcelona, Spain.
When the Master of Science Course on Computational Mechanics began, the Director of the Master asked me to take charge and to develop a course on Continuum Mechanics. The course should have around 40-45 class hours and  would be scheduled to be taught in the first semester of the first year of the Master. I embarked on this path by designing and developing what has been my flagship and signature course on Continuum Mechanics.

This book has been designed as an updated and expanded version of my Continuum Mechanics lecture notes and has been structured in 10 chapters. As an introduction, Chapters 1 and 2 are devoted to Tensor Algebra and Tensor Analysis. Part I of the book includes the next 3 chapters. Chapter 3 is devoted to Nonlinear Kinematics, Chapter 4 deals with Stresses, and Chapter 5 addresses the Fundamental Conservation/Balance Laws. Part II includes the next 4 chapters. Chapter 6 is devoted to Finite Deformation Hyperelasticity, Chapter 7 to Finite Deformation Plasticity, Chapter 8 to Finite Deformation Coupled Thermoplasticity, and Chapter 9 to Finite Deformation Contact Mechanics. The last chapter, Chapter 10, deals with Variational Methods in Solid Mechanics, including coupled thermoplasticity and contact problems.

The common feature of Part I is that all the contents are always valid, regardless of the material, be it solid or fluid. At the end of Part I we should be able to set up in local spatial/material form, the fundamental governing equations and inequalities for a Continuum Mechanics problem. The fundamental governing equations and inequalities arise from the fundamental conservation/balance principles and from the constraints imposed by the second law of thermodynamics, and are valid for any material. At the end of Part I, we should be able to check how many governing equations we have, and how many unknowns are involved in those governing equations and inequalities. We will realize that we have more unknowns than equations. So, to have a well posed problem, we would need to add a number of equations, so that the final number of equations is equal to the number of unknowns. The equations we should add would depend on the material and for some particular material models will be considered in Part II of the book.

Part II of the book is devoted to presenting some nonlinear constitutive models for Nonlinear Solid Mechanics, including Finite Deformation Hyperelasticity, Finite Deformation Plasticity, Finite Deformation Coupled Thermoplasticity, and Finite Deformation Contact Mechanics. Constitutive equations are derived within a thermodynamically consistent framework. Finite deformation elastoplasticity models are based on the multiplicative decomposition of the deformation gradient and the notion of an intermediate configuration. Different formulations based on the intermediate configuration, the current or spatial configuration, and the material configuration, are considered. The last chapter is devoted to Variational Methods in Solid Mechanics, a fundamental topic in Computational Mechanics.

The book may be used as a text book for a Master’s course on Nonlinear Continuum Mechanics for graduate students in Civil, Mechanical or Aerospace Engineering, Applied Mathematics or Applied Physics, with interest in Continuum Mechanics and Computational Mechanics.

I am grateful to my colleagues and friends Jean-Philippe Ponthot at University of Liege, and Mariana Seabra at University of Porto for their careful reading of the manuscript.

I hope you enjoy reading the book as much as I have enjoyed writing it.

Carlos Agelet de Saracibar
Barcelona, Spain, 22 March 2022

An approximation model based on convolutional neural networks (CNNs) is proposed for flow field predictions. The CNN is used to predict the velocity and pressure field in unseen flow conditions and geometries given the pixelated shape of the object. In particular, we consider Reynolds Averaged Navier-Stokes (RANS) flow solutions over airfoil shapes. The CNN can automatically detect essential features with minimal human supervision and shown to effectively estimate the velocity and pressure field orders of magnitude faster than the RANS solver, making it possible to study the impact of the airfoil shape and operating conditions on the aerodynamic forces and the flow field in near-real time. The use of specific convolution operations, parameter sharing, and robustness to noise are shown to enhance the predictive capabilities of CNN. We explore the network architecture and its effectiveness in predicting the flow field for different airfoil shapes, angles of attack, and Reynolds numbers.

This special volume is dedicated to Thomas J. R. Hughes, a phenomenal leader in computational mechanics, on the occasion of his 65th birthday. A sequence of symposia organized at the Fifteenth International Conference on Finite Elements in Flow Problems, Tokyo, Japan, April 1-3, 2009, were dedicated to the celebration of this occasion. This special volume contains papers authored by friends, colleagues, collaborators and former students of Tom Hughes who gave presentations at these symposia. It is a tribute to the A. Masud (B)

ABSTRACT

This study focuses on the deformation behaviour of organic materials under a drop case. A Golden Delicious
apple was chosen as the sample organic material. A three-dimensional (3D) scanner, high speed
camera and finite element method (FEM) simulations were utilised to investigate drop case deformation
events of the organic material. In total, 22 steps after impact were set up in the simulation by comparing
high speed camera screen steps. Maximum equivalent stress of 0.416 MPa and maximum contact force
(resultant normal force from rigid plane at impact) of 250.980 N were obtained from simulation results.
Visual investigations and simulation results relating to deformations observed under the drop case,
agreed well. This study contributes to further our understanding of fruit and vegetable damage/deformation
by using computer aided engineering applications.


Keywords:

Drop test, Finite element method, Organic materials, Golden Delicious apple

A center stand is a device on a bicycle or motorcycle that allows the bike to be kept upright without leaning against another object or the aid of a person. A center stand is usually a made of metal that comes down from the frame and makes contact with the ground. It is generally located in the middle of the bike or towards the rear. Some touring bicycles have two: one at the rear, and a second in the front. A new standing device which replaces center stand using external power which reduces human effort is being proposed. An existing center stand is modified by using electrical and mechanical components at optimum cost. The different mechanical parameters of stand are analyzed using Computational software and the best model is selected for fabrication.

Studying heat transfer through computational methods is increasing in importance, and this volume is right in step with the times. It presents the fundamentals for computational work and offers a wide range of methods useful with basic processes and applied problems of heat transfer ...

Course is intended for Undergraduate Mechanical Engineering students involving on Understanding Kinematics of Mechanisms, simple mechanism study,  Velocity and acceleration analysis of mechanisms, Problem solving on Belt drives, Rope drives, Using Graphical analysis of generating Cam Profiles, Study of all types of gear drives and problem solving on spur gears, study on control and regulation of Governors.

A computational vascular fluid-structure interaction framework for the simulation of patientspecific cerebral aneurysm configurations is presented. A new approach for the computation of the blood vessel tissue prestress is also described. Simulations of four patient-specific models are carried out, and quantities of hemodynamic interest such as wall shear stress and wall tension are studied to examine the relevance of fluid-structure interaction modeling when compared to the rigid arterial wall assumption. We demonstrate that flexible wall modeling plays an important role in accurate prediction of patient-specific hemodynamics. Discussion of the clinical relevance of our methods and results is provided.

In this paper, a twenty storey multi-storey rigid frame was subjected to a uniformly distributed wind pressure load of 5.05 KN/m 2. The deflection behaviour of the rigid frame was investigated using manual method, and computer based method (finite element analysis). From the results of the two methods employed, it is observed that the value obtained from manual method gave a lower value for the top deflection of the building. The maximum deflection from finite element was 60.441mm, while the result from manual calculation was 55.524mm. This shows that the result from finite element analysis to manual method was about 8.135% greater than that of the manual method. However, this offers a great insight for the speedy check of computer based processes and results.