Strain Hardening From Elastic-Perfectly Plastic to Perfectly Elastic Indentation Single Asperity Contact

Ghaednia, Hamid; Mifflin, Gregory; Lunia, Priyansh; ONeill, Eoghan Oisin; Brake, Matthew Robert

doi:10.3389/fmech.2020.00060

Cited by 13 publications

(6 citation statements)

References 54 publications

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“…The plane section assumption: After bending, the blank cross section, which is perpendicular to the fiber, is still a plane (Boisse et al , 2018). The material is elastic-perfectly plastic material, so there is no strain hardening while deforming (Ghaednia et al , 2020). The TA is in the inner bending arc (Zhu et al , 2007).…”

Section: Research Hypothesesmentioning

confidence: 99%

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Research on the laws of transition zone of non-deformation area for 90° V-bending forming process

Miah

Zhang

Malhi

2022

AEAT

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Purpose “V-bending” is the most commonly used bending process in which the sheet metal is pressed into a “V-shaped” die using a “V-shaped” punch to form a required angular bend. When the punch is removed after the operation, because of elastic recovery, the bent angle varies. This shape discrepancy is known as spring back which causes problems in the assembly of the component in the modern aerospace industry. Regarding the optimization of spring-back accuracy, this research will illustrate the laws of the transition area (TA) of the nondeformation area (NDA) during the 90° “V-shape” bending process. Design/methodology/approach According to the traditional “V-bending” process to optimize the spring-back accuracy, the bent sheets are divided into deformation area (DA) and NDA. For this reason, the traditional “V-bending” process may prolong error to optimize the spring-back accuracy because NDA has a certain amount of deformation, which the researcher always avoids. Firstly, bent sheets are divided into three parts in this research: DA, TA and NDA to avoid the distortion error in TA that are not considered in the NDA in traditional theory. Then, the stress and strain in the DA and TA were discussed during theoretical derivation and some hypotheses were proposed. In this research, the interval, position and distortion degree of the TA of the bending sheet are used by finite element analysis. Finally, V-shape bending tests for aluminum alloy at room temperature are used and labeled all the work pieces' TAs to realize the deformation amount in the TA. Findings The bending radius does not affect the range of the TA, it only changes the position of TA in the bending sheet. It is evident that the laws of TA were explored in the width direction and gradually changed from the inner layer to the outer layer based on the ratio of width and thickness of the bending plate/sheet. Originality/value In the modern aerospace industry, aircraft manufacturing technology must maintain high accuracy. This research has practical value in the 90° “V-shape” bending of metal sheets and the development of its spring-back accuracy.

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Section: Research Hypothesesmentioning

confidence: 99%

“…The material is elastic-perfectly plastic material, so there is no strain hardening while deforming (Ghaednia et al , 2020).…”

Section: Research Hypothesesmentioning

confidence: 99%

Research on the laws of transition zone of non-deformation area for 90° V-bending forming process

Miah

Zhang

Malhi

2022

AEAT

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“…They concluded that a single synthetic measure of initial particle deformation relative to deformation at first yield is insufficient to characterize the unloading response at large displacements when considering both stiffness and nonlinearity results. Ghaednia et al presented new formulations for single asperity frictionless indentation contact [ 44 ] and flattening contact [ 45 ] considering the effect of bilinear strain hardening. The deformations on both of the objects, real contact radius and contact force have been considered in the model.…”

Section: Introductionmentioning

confidence: 99%

Unloading Model of Elastic–Plastic Half-Space Contacted by an Elastic Spherical Indenter

Xie,

Guo,

Ding

et al. 2024

Materials

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A new unloading contact model of an elastic–perfectly plastic half-space indented by an elastic spherical indenter is presented analytically. The recovered deformation of the elastic indenter and the indented half-space has been found to be dependent on the elastic modulus ratio after fully unloading. The recovered deformation of the indented half-space can be calculated based on the deformation of the purely elastic indenter. The unloading process is assumed to be entirely elastic, and then the relationship of contact force and indentation can be determined based on the solved recovered deformation and conforms to Hertzian-type. The model can accurately predict the residual indentation and residual curvature radius after fully unloading. Numerical simulations are performed to demonstrate the assumptions and the unloading model. The proposed unloading model can cover a wide range of indentations and material properties and is compared with existing unloading models. The cyclic behavior including loading and unloading can be predicted by combining the proposed unloading law with the existing contact loading model. The combined model can be employed for low-velocity impact and nanoindentation tests and the comparison results are in good agreement.

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“…They also presented a formula for calculating F/F c and A/A c in the elastic-plastic range. Recently, Gheadnia et al [45][46][47] analyzed elastic-plastic contact behavior between the deformable hemisphere and the flat using FEM by controlling the yield strength ratio between hemisphere and flat (Y 1 /Y 2 ). They demonstrated that the elastic-plastic contact behavior is related to the Y 1 /Y 2 ratio.…”

Section: Introductionmentioning

confidence: 99%

Research on Elastic–Plastic Contact Behavior of Hemisphere Flattened by a Rigid Flat

et al. 2022

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The contact behavior of a hemisphere pressed by a rigid plane is of great significance to the study of friction, wear, and conduction between two rough surfaces. A flattening contact behavior of an elastic–perfectly plastic hemisphere pressed by a rigid flat is researched by using the finite element method in this paper. This behavior, influenced by different elastic moduli, Poisson’s ratios, and yield strengths, is compared and analyzed in a large range of interference values, which have not been considered by previous models. The boundaries of purely elastic, elastic–plastic, and fully plastic deformation regions are given according to the interference, maximum mean contact pressure, Poisson’s ratio, and elastic modulus to yield strength ratio. Then, a new elastic–plastic constitutive model is proposed to predict the contact area and load in the elastic–plastic range. Compared with previous models and experiments, the rationality of the present model is verified. The study can be applied directly to the contact between a single sphere and a plane. In addition, the sphere contact can also be used to simulate the contact of single asperity on rough surfaces, so the present proposed model can be used to further study the contact characteristics of rough surfaces.

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Strain Hardening From Elastic-Perfectly Plastic to Perfectly Elastic Indentation Single Asperity Contact

Cited by 13 publications

References 54 publications

Research on the laws of transition zone of non-deformation area for 90° V-bending forming process

Research on the laws of transition zone of non-deformation area for 90° V-bending forming process

Unloading Model of Elastic–Plastic Half-Space Contacted by an Elastic Spherical Indenter

Research on Elastic–Plastic Contact Behavior of Hemisphere Flattened by a Rigid Flat

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