Mean stress dependence of the thermoelastic constant

A formal relationship is established between the traditional bulk fatigue criteria such as the Goodman rule and the Sines criterion, and the recent crack initiation criterion of Dang Van. The constants implied by the Dang Van procedure may be formally connected to the fatigue limit and mean stress dependence given by the Goodman rule, under conditions of uniaxial loading. The biaxial fatigue criterion of Sines is also compared with the Dang Van procedure. The similarity in the approaches may be further extended to permit finite initiation times to be estimated by the Dang Van criterion when the fatigue limit is exceeded.

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421 Finite Element Analyses of BMG based on non-Associated Flow rule with Mean Stress Dependence

The Proceedings of Conference of Kansai Branch ◽

10.1299/jsmekansai.2013.88._4-21_ ◽

2013 ◽

Vol 2013.88 (0) ◽

pp. _4-21_

Author(s):

Hideto MIMA ◽

Yoji SHIBUTANI

Keyword(s):

Finite Element ◽

Flow Rule ◽

Mean Stress ◽

Stress Dependence ◽

Finite Element Analyses ◽

Associated Flow Rule

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Comparative study of the effective parameters on residual stress relaxation in welded aluminum plates under cyclic loading

Mechanics & Industry ◽

10.1051/meca/2020061 ◽

2020 ◽

Vol 21 (5) ◽

pp. 505

Author(s):

Yousef Ghaderi Dehkordi ◽

Ali Pourkamali Anaraki ◽

Amir Reza Shahani

Keyword(s):

Residual Stress ◽

Cyclic Loading ◽

Stress Relaxation ◽

Stress Amplitude ◽

Cyclic Plasticity ◽

Mean Stress ◽

Effective Parameters ◽

Perfect Plasticity ◽

Residual Stress Relaxation ◽

Aluminum Plates

The prediction of residual stress relaxation is essential to assess the safety of welded components. This paper aims to study the influence of various effective parameters on residual stress relaxation under cyclic loading. In this regard, a 3D finite element modeling is performed to determine the residual stress in welded aluminum plates. The accuracy of this analysis is verified through experiment. To study the plasticity effect on stress relaxation, two plasticity models are implemented: perfect plasticity and combined isotropic-kinematic hardening. Hence, cyclic plasticity characterization of the material is specified by low cycle fatigue tests. It is found that the perfect plasticity leads to greater stress relaxation. In order to propose an accurate model to compute the residual stress relaxation, the Taguchi L18 array with four 3-level factors and one 6-level is employed. Using statistical analysis, the order of factors based on their effect on stress relaxation is determined as mean stress, stress amplitude, initial residual stress, and number of cycles. In addition, the stress relaxation increases with an increase in mean stress and stress amplitude.

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