scholarly journals Dependence of strain-hardening under multiaxial non-proportional cyclic plastic deformation on amplitude history of plastic strain.

1985 ◽  
Vol 51 (469) ◽  
pp. 2162-2171
Author(s):  
Eiichi TANAKA ◽  
Sumio MURAKAMI ◽  
Masahiro OOKA
Keyword(s):  
Plastic Deformation ◽  
Plastic Strain ◽  
Strain Hardening ◽  
Cyclic Plastic ◽  
History Of ◽  
Cyclic Plastic Deformation

scholarly journals Numerical Prediction of the Fatigue Crack Growth Rate in SLM Ti-6Al-4V Based on Crack Tip Plastic Strain

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1133
Author(s):  
Fábio F. Ferreira ◽  
Diogo M. Neto ◽  
Joel S. Jesus ◽  
Pedro A. Prates ◽  
Fernando V. Antunes
Keyword(s):  
Growth Rate ◽  
Plastic Deformation ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Plastic Strain ◽  
Crack Growth ◽  
Stress Ratio ◽  
Cyclic Plastic ◽  
Cyclic Plastic Deformation

This study presents a numerical model to predict the fatigue crack growth (FCG) rate in compact tension specimens under constant amplitude cyclic loadings. The material studied is the Ti-6Al-4V titanium alloy produced by selective laser melting, which was submitted to two different post-treatments: (i) hot isostatic pressing, and (ii) heat treatment. The developed finite element model uses the cumulative plastic strain at the crack tip to define the nodal release. Two different FCG criteria are presented, namely the incremental plastic strain (IPS) criterion and the total plastic strain (TPS) criterion. The calibration of the elasto-plastic constitutive model was carried out using experimental data from low cycle fatigue tests of smooth specimens. For both proposed crack growth criteria, the predicted da/dN-ΔK curve is approximately linear in log-log scale. However, the slope of the curve is higher using the TPS criterion. The numerical predictions of the crack growth rate are in good agreement with the experimental results, which indicates that cyclic plastic deformation is the main damage mechanism. The numerical results showed that increasing the stress ratio leads to a shift up of the da/dN-ΔK curve. The effect of stress ratio was dissociated from variations of cyclic plastic deformation, and an extrinsic mechanism, i.e., crack closure phenomenon, was found to be the cause.

The Effect of Plastic Deformation on the Thermoelastic Constant and the Potential to Evaluate Residual Stress

2011 ◽  
Vol 70 ◽  
pp. 458-463 ◽  
Author(s):  
A. F. Robinson ◽  
Janice M. Dulieu-Barton ◽  
S. Quinn ◽  
R. L. Burguete
Keyword(s):  
Residual Stress ◽  
Plastic Deformation ◽  
Plastic Strain ◽  
Strain Hardening ◽  
Thermoelastic Stress ◽  
Paint Coating ◽  
Full Field ◽  
Thermoelastic Constant ◽  
Thermoelastic Response ◽  
Measured Change

In some metals it has been shown that the introduction of plastic deformation or strain modifies the thermoelastic constant, K. If it was possible to define the magnitude of the change in thermoelastic constant over a range of plastic strain, then the plastic strain that a material has experienced could be established based on a measured change in the thermoelastic constant. This variation of the thermoelastic constant and the ability to estimate the plastic strain that has been experienced, has potential to form the basis of a novel non-destructive, non-contact, full-field technique for residual stress assessment using thermoelastic stress analysis (TSA). Recent research has suggested that the change in thermoelastic constant is related to the material dislocation that occurs during strain hardening, and thus the change in K for a material that does not strain harden would be significantly less than for a material that does. In the work described in this paper, the change in thermoelastic constant for three materials (316L stainless steel, AA2024 and AA7085) with different strain hardening characteristics is investigated. As the change in thermoelastic response due to plastic strain is small, and metallic specimens require a paint coating for TSA, the effects of the paint coating and other test factors on the thermoelastic response have been considered.

An Experimental Study of Inhomogeneous Cyclic Plastic Deformation

2001 ◽  
Vol 123 (3) ◽  
pp. 274-280 ◽  
Author(s):  
Yanyao Jiang
Keyword(s):  
Plastic Deformation ◽  
Cyclic Loading ◽  
Small Strain ◽  
Local Deformation ◽  
Gage Section ◽  
Strain Gages ◽  
Cyclic Plastic ◽  
Symmetrical Loading ◽  
Increasing Cyclic Loading ◽  
Cyclic Plastic Deformation

A localized inhomogeneous cyclic plastic deformation phenomenon was experimentally investigated in a mild steel. Small strain gages were utilized to characterize the local deformation within the gage section and the gross deformation was measured with an extensometer. Both fully reversed symmetrical loading and asymmetrical loading with a mean stress were used in the cyclic experiments. Plastic deformation was initiated in local areas of the specimen and it propagated into the whole gage section in the specimen with increasing cyclic loading. The local inhomogeneous cyclic deformation was dependent on the loading magnitude and evolved with continued cyclic loading.

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