Shock Thickness in Viscoplastic Solids

1970 ◽  
Vol 37 (1) ◽  
pp. 163-170 ◽  
Author(s):  
J. M. Kelly ◽  
P. P. Gillis
Keyword(s):  
Plastic Strain ◽  
Strain Rate ◽  
Finite Deformation ◽  
Constitutive Equations ◽  
Wave Speed ◽  
Constitutive Relations ◽  
Plastic Strain Rate ◽  
Plastic Materials ◽  
Elastic Plastic Materials ◽  
Viscoplastic Solids

In this paper a system of constitutive relations for plane-strain finite deformation in strain-rate sensitive elastic-plastic materials is developed. A method is presented for computing the main features of steady-state one-dimensional plastic-strain waves by elementary numerical techniques in materials of this type. This method is applicable to a wide variety of material constitutive relations and provides an alternative to computing complete wave profiles for investigators interested primarily in the effects of certain numerical parameters on the principal features of waves. The method is illustrated by use of particular constitutive relations but is applicable to a much wider class of relations. Maximum normal stress, pressure, and shear stress are computed, using this method, as a function of wave speed. For two different plastic strain-rate relations the maximum plastic strain rate and total strain are computed as a function of wave speed. Making use of these results, estimates are provided for the wave-front thickness in terms of wave speed and the parameters of the particular viscoplastic constitutive equations used. These results suggest ways in which plastic wave experiments can be used to motivate the construction of constitutive equations for finite deformation in strain-rate sensitive plastic solids.

An Experimental Study on the Effect of Prior Plastic Straining on Creep Behavior of 304 Stainless Steel

1993 ◽  
Vol 115 (2) ◽  
pp. 200-203 ◽  
Author(s):  
Z. Xia ◽  
F. Ellyin
Keyword(s):  
Stainless Steel ◽  
Plastic Strain ◽  
Strain Rate ◽  
Creep Behavior ◽  
Test Procedure ◽  
Constant Strain Rate ◽  
304 Stainless Steel ◽  
Creep Model ◽  
Plastic Strain Rate ◽  
Creep Tests

Constant strain-rate plastic straining followed by creep tests were conducted to investigate the effect of prior plastic straining on the subsequent creep behavior of 304 stainless steel at room temperature. The effects of plastic strain and plastic strain-rate were delineated by a specially designed test procedure, and it is found that both factors have a strong influence on the subsequent creep deformation. A creep model combining the two factors is then developed. The predictions of the model are in good agreement with the test results.

An Assessment of the Method Used to Determine Activation Parameters in L12 Alloys

1998 ◽  
Vol 552 ◽  
Author(s):  
B. Matterstock ◽  
G. Saada ◽  
J. Bonneville ◽  
J. L Martin
Keyword(s):  
Mechanical Properties ◽  
Theoretical Analysis ◽  
Plastic Strain ◽  
Strain Rate ◽  
Characteristic Time ◽  
Constant Strain Rate ◽  
Activation Parameters ◽  
Plastic Strain Rate ◽  
Clear Indication ◽  
Load Relaxation

ABSTRACTThe characterisation of dislocation mechanisms in connection with macroscopic mechanical properties are usually performed through transient tests, such as strain-rate jumps, load relaxations or creep experiments. The present paper includes a careful and complete theoretical analysis of the relaxation and the creep kinetics. We experimentally show that the plastic strain-rate is continuous at the transition between constant strain-rate conditions and both load relaxation and creep test. The product of the plastic strain-rate at the onset of the transient test () with the characteristic time (tk) of the transient is found to be independent of , as theoretically expected. This is a clear indication that the assumptions underlying the theoretical analysis are relevant.

Calculation of Material Flow in Orthogonal Cutting by Using Streamline Model

2009 ◽  
Vol 407-408 ◽  
pp. 490-493 ◽  
Author(s):  
Xue Feng Bi ◽  
Gautier List ◽  
Yong Xian Liu
Keyword(s):  
Plastic Strain ◽  
Strain Rate ◽  
Line Shape ◽  
Material Flow ◽  
General Equation ◽  
Flow Line ◽  
Orthogonal Cutting ◽  
Plastic Strain Rate ◽  
Complex Variation ◽  
Streamline Method

The streamline method was used to investigate the plastic strain rate in machining. The streamline function presented in this paper is a general equation with three parameters controlling the complex variation of flow line shape. Velocity and deformation field were obtained by streamline analysis. The validation of this model was conducted by comparing with other experimental results published. It shows that the streamline model presented in the paper can be applied to the evaluation of strain rate in machining.

scholarly journals How to Realize Volume Conservation During Finite Plastic Deformation

2017 ◽  
Vol 84 (11) ◽  
Author(s):  
Heling Wang ◽  
Dong-Jie Jiang ◽  
Li-Yuan Zhang ◽  
Bin Liu
Keyword(s):  
Plastic Deformation ◽  
Plastic Strain ◽  
Strain Rate ◽  
Plastic Strain Rate ◽  
Strain Rate Tensor ◽  
Cauchy Stress ◽  
Volume Conservation ◽  
Tangential Stiffness ◽  
Manufacture Process ◽  
Universal Approach

Volume conservation during plastic deformation is the most important feature and should be realized in elastoplastic theories. However, it is found in this paper that an elastoplastic theory is not volume conserved if it improperly sets an arbitrary plastic strain rate tensor to be deviatoric. We discuss how to rigorously realize volume conservation in finite strain regime, especially when the unloading stress free configuration is not adopted in the elastoplastic theories. An accurate condition of volume conservation is first clarified and used in this paper that the density of a volume element after the applied loads are completely removed should be identical to that of the initial stress free states. For the elastoplastic theories that adopt the unloading stress free configuration (i.e., the intermediate configuration), the accurate condition of volume conservation is satisfied only if specific definitions of the plastic strain rate are used among many other different definitions. For the elastoplastic theories that do not adopt the unloading stress free configuration, it is even more difficult to realize volume conservation as the information of the stress free configuration lacks. To find a universal approach of realizing volume conservation for elastoplastic theories whether or not adopt the unloading stress free configuration, we propose a single assumption that the density of material only depends on the trace of the Cauchy stress by using their objectivities. Two strategies are further discussed to satisfy the accurate condition of volume conservation: directly and slightly revising the tangential stiffness tensor or using a properly chosen stress/strain measure and elastic compliance tensor. They are implemented into existing elastoplastic theories, and the volume conservation is demonstrated by both theoretical proof and numerical examples. The potential application of the proposed theories is a better simulation of manufacture process such as metal forming.

Transient functions for plastic strain rate changes

1976 ◽  
Vol 38 (2) ◽  
pp. 539-546 ◽  
Author(s):  
B. Wielke ◽  
G. Schoeck
Keyword(s):  
Plastic Strain ◽  
Strain Rate ◽  
Plastic Strain Rate
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