In this paper, an adopted abrasive-diffusive wear model is proposed and implemented into a 3D Fin... more In this paper, an adopted abrasive-diffusive wear model is proposed and implemented into a 3D Finite Element code to study the tool wear phenomenon. In particular, the Authors found that FE procedure based only on diffusive mechanism shown some problems when the extension on crater area was investigated. This can be related to the absence of the wear abrasion term on the utilized model. Therefore, in this work, the Authors improved the previous utilized tool wear model introducing into the sub-routine the abrasive term on the basis of Usui's model. A series of 3D FEM simulations were conducted in order to estimate the tool wear development in turning operations. The adopted abrasive-diffusive wear model will give the possibility of correctly evaluating the tool wear of actual turning operations during both the initial transient phase, where the abrasive mechanism is dominant, and the steady-state phase, in which the diffusion is the main wear mechanism. The FEM results were compared with experimental data, obtained turning AISI 1045 steel with WIDIA P40 inserts, showing a satisfactory agreement.
Twin-disc rolling/sliding tribometer experiments try to mimic the rolling/sliding contact experie... more Twin-disc rolling/sliding tribometer experiments try to mimic the rolling/sliding contact experienced by micro-machines, e.g., between the teeth of two mating micro-gears. In this work, a user defined subroutine UMESHMOTION, in the commercial finite element code, ABAQUS, has been applied to simulate wear in a twin-disc tribometer experiments, conducted for defined slips. ABAQUS invokes the adaptive meshing algorithm after the convergence of the equilibrium equations of the contact problem, which further, invokes the user defined sub-routine UMESHMOTION. UMESHMOTION is coded to compute the local wear using the generalized Archard's wear model and it integrates the wear depth over the sliding distance using Euler integration scheme. In the absence of wear coefficient data from such experiments, it is assumed to be the same as identified from pinon-disc experiments . The computed wear is applied on each surface node as mesh-constraint by the adaptive meshing algorithm. The resulting equilibrium loss is corrected by solving the last time increment. Thus the geometry and pressures are updated. Simulations were carried out with different applied loads (with constant slip) and different slips (with constant load) and the results obtained, are presented. The results obtained from UMESHMOTION are discussed by comparing them with the Global Incremental Wear Model (GIWM) and the Wear-Processor (Hegadekatte, 2006a).
Study of wear in complex micro-mechanical components is often accomplished experimentally using a... more Study of wear in complex micro-mechanical components is often accomplished experimentally using a pinon-disc and twin-disc tribometer. The present paper proposes an approach that involves a computationally efficient incremental implementation of Archard's wear model on the global scale for modeling sliding and slipping wear in such experiments. It will be shown that this fast simplistic numerical tool can be used to identify the wear coefficient from pin-on-disc experimental data and also predict the wear depths within a limited range of parameter variation. Further it will also be used to study the effect of introducing friction coefficient into the wear model and also to model water lubricated experiments. A similar tool is presented to model wear due to a defined slip in a twin-disc tribometer. The resulting wear depths from this tool is verified using experimental data and two different finite element based numerical tools namely, the Wear-Processor, which is a FE post processor, and a user-defined subroutine UMESHMOTION in the commercial FE package ABAQUS. It will be shown that the latter two tools have the potential for use in predicting wear and the effective life span of any general tribosystem using the identified wear coefficient from relevant tribometry data. wear model, its limitations, and to identify phenomena, which require the implementation of improved mechanistic models. In a further step, which is not in the scope of the present paper, one can develop an experimental design, which allows to identify and quantify the relevant wear mechanisms for further model development. 4 5 6 7 8 subscript 1 and 2 correspond to the curved and the flat disc respectively and E C is the elastic modulus of the equivalent surface calculated using Equation 3.
In this paper, an adopted abrasive-diffusive wear model is proposed and implemented into a 3D Fin... more In this paper, an adopted abrasive-diffusive wear model is proposed and implemented into a 3D Finite Element code to study the tool wear phenomenon. In particular, the Authors found that FE procedure based only on diffusive mechanism shown some problems when the extension on crater area was investigated. This can be related to the absence of the wear abrasion term on the utilized model. Therefore, in this work, the Authors improved the previous utilized tool wear model introducing into the sub-routine the abrasive term on the basis of Usui's model. A series of 3D FEM simulations were conducted in order to estimate the tool wear development in turning operations. The adopted abrasive-diffusive wear model will give the possibility of correctly evaluating the tool wear of actual turning operations during both the initial transient phase, where the abrasive mechanism is dominant, and the steady-state phase, in which the diffusion is the main wear mechanism. The FEM results were compared with experimental data, obtained turning AISI 1045 steel with WIDIA P40 inserts, showing a satisfactory agreement.
Twin-disc rolling/sliding tribometer experiments try to mimic the rolling/sliding contact experie... more Twin-disc rolling/sliding tribometer experiments try to mimic the rolling/sliding contact experienced by micro-machines, e.g., between the teeth of two mating micro-gears. In this work, a user defined subroutine UMESHMOTION, in the commercial finite element code, ABAQUS, has been applied to simulate wear in a twin-disc tribometer experiments, conducted for defined slips. ABAQUS invokes the adaptive meshing algorithm after the convergence of the equilibrium equations of the contact problem, which further, invokes the user defined sub-routine UMESHMOTION. UMESHMOTION is coded to compute the local wear using the generalized Archard's wear model and it integrates the wear depth over the sliding distance using Euler integration scheme. In the absence of wear coefficient data from such experiments, it is assumed to be the same as identified from pinon-disc experiments . The computed wear is applied on each surface node as mesh-constraint by the adaptive meshing algorithm. The resulting equilibrium loss is corrected by solving the last time increment. Thus the geometry and pressures are updated. Simulations were carried out with different applied loads (with constant slip) and different slips (with constant load) and the results obtained, are presented. The results obtained from UMESHMOTION are discussed by comparing them with the Global Incremental Wear Model (GIWM) and the Wear-Processor (Hegadekatte, 2006a).
Study of wear in complex micro-mechanical components is often accomplished experimentally using a... more Study of wear in complex micro-mechanical components is often accomplished experimentally using a pinon-disc and twin-disc tribometer. The present paper proposes an approach that involves a computationally efficient incremental implementation of Archard's wear model on the global scale for modeling sliding and slipping wear in such experiments. It will be shown that this fast simplistic numerical tool can be used to identify the wear coefficient from pin-on-disc experimental data and also predict the wear depths within a limited range of parameter variation. Further it will also be used to study the effect of introducing friction coefficient into the wear model and also to model water lubricated experiments. A similar tool is presented to model wear due to a defined slip in a twin-disc tribometer. The resulting wear depths from this tool is verified using experimental data and two different finite element based numerical tools namely, the Wear-Processor, which is a FE post processor, and a user-defined subroutine UMESHMOTION in the commercial FE package ABAQUS. It will be shown that the latter two tools have the potential for use in predicting wear and the effective life span of any general tribosystem using the identified wear coefficient from relevant tribometry data. wear model, its limitations, and to identify phenomena, which require the implementation of improved mechanistic models. In a further step, which is not in the scope of the present paper, one can develop an experimental design, which allows to identify and quantify the relevant wear mechanisms for further model development. 4 5 6 7 8 subscript 1 and 2 correspond to the curved and the flat disc respectively and E C is the elastic modulus of the equivalent surface calculated using Equation 3.
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