scholarly journals Closure to “Discussions of ‘The Propagation of Longitudinal Waves of Plastic Deformation in a Bar of Material Exhibiting a Strain-Rate Effect’” (1951, ASME J. Appl. Mech., 18, pp. 428–429)

1951 ◽  
Vol 18 (4) ◽  
pp. 429
Author(s):  
L. E. Malvern
Keyword(s):  
Plastic Deformation ◽  
Strain Rate ◽  
Strain Rate Effect ◽  
Rate Effect ◽  
Longitudinal Waves

The Propagation of Longitudinal Waves of Plastic Deformation in a Bar of Material Exhibiting a Strain-Rate Effect

1951 ◽  
Vol 18 (2) ◽  
pp. 203-208 ◽  
Author(s):  
L. E. Malvern
Keyword(s):  
Plastic Deformation ◽  
Plastic Strain ◽  
Strain Rate ◽  
Strain Rate Effect ◽  
Rate Effect ◽  
Longitudinal Waves ◽  
Strain And Strain Rate ◽  
Flow Law

Abstract The theory of propagation of longitudinal waves of plastic deformation is extended to apply to materials in which the stress is a function of the instantaneous plastic strain and strain rate. Solutions are given for an idealized flow law and compared with solutions based upon earlier theories which neglect strain-rate effect.

scholarly journals Effect of Strain Rate on the Deformation Characteristic of AlN Ceramics under Scratching

Micromachines ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 77
Author(s):  
Shang Gao ◽  
Honggang Li ◽  
Renke Kang ◽  
Yu Zhang ◽  
Zhigang Dong
Keyword(s):  
Plastic Deformation ◽  
Stress Field ◽  
Strain Rate ◽  
Penetration Depth ◽  
Elastic Recovery ◽  
Deformation Characteristic ◽  
Strain Rate Effect ◽  
Rate Effect ◽  
Deformation Characteristics ◽  
Berkovich Indenter

To clarify the influence mechanism of strain rate effect on deformation characteristics of aluminum nitride (AlN) ceramics, some varied-velocity nanoscratching tests were carried out using a Berkovich indenter in this paper. The deformation characteristics of the scratched grooves were observed using the scanning electron microscope. The experimental results showed higher scratch speed would lead to shallower penetration depth, fewer cracks, and indenter fewer slipping, which was more conducive to the plastic deformation of AlN ceramics. Considering the strain rate effect and the elastic recovery of material, a model for predicting the Berkovich indenter penetration depth under edge-forward mode was established. The prediction results were consistent with the experimental data, and the error was less than 5%, indicating that the model is effective. Based on the Boussinesq field, the Cerruti field, and the Sliding bubble field, a strain rate dependent scratch stress field model was established. The stress field revealed higher scratch speed may significantly reduce the maximum principal stress in the stress field under the indenter, which is the fundamental reason for reducing the crack damage and promoting the plastic deformation. The above study can provide theoretical guidance for reducing the processing damage of AlN ceramics.

Study of the Strain Rate Effect on Cold-Reduced Carbon Steel and Aluminium Alloy with Numerical Simulations

2006 ◽  
Vol 532-533 ◽  
pp. 973-976
Author(s):  
Lin Wang ◽  
Tai Chiu Lee ◽  
Luen Chow Chan
Keyword(s):  
Carbon Steel ◽  
Strain Rate ◽  
Strain Path ◽  
Plastic Material ◽  
Strain Rate Effect ◽  
Rate Effect ◽  
Forming Process ◽  
Risk Area ◽  
Sensitive Material ◽  
Simulation Results

In this paper, the effect of strain rate has been considered in the simulation of forming process with a simple form combined into the material law. Quite a few researchers have proposed various hardening laws and strain rate functions to describe the material tensile curve. In this study, the strain rate model Cowper-Symonds is used with anisotropic elasto-plastic material law in the simulation process. The strain path evolution of certain elements, when the strain rate is considered and not, is compared. Two sheet materials, Cold-reduced Carbon Steel (SPCC) JIS G3141 and Aluminum alloy 6112 are used in this study. Two yield criteria, Hill 48 and Hill 90, are applied respectively to improve the accuracy of simulation result. They show different performance when strain rate effect is considered. Strain path of the elements in the fracture risk area of SPCC (JIS G3141) varies much when the strain rate material law is used. There is only little difference of the strain distribution of Al 6112 when the strain rate effect is included and excluded in the material law. The simulation results of material SPCC under two conditions indicate that the strain rate should be considered if the material is the rate-sensitive material, which provides more accurate simulation results.

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