Frequency-dependent cohesive-zone model for fatigue

Abstract

This paper is concerned with the development and application of a frequency-dependent cohesive-zone model (CZM) for crack-growth analysis of low and high-cycle fatigue. The new model makes use of recent advances by combining a modified version of a recently developed frequency-dependent trapezoidal cohesive-zone model [1] and a new loadingunloading hysteresis damage model with fast-track facility. The new combined model offers an alternative approach to capture frequency effects and at the same time deliver accuracy comparable to the loading-unloading hysteresis damage model along with the computational efficiency of the equally well-established envelope load-damage model. The model provides for the first time a methodology that accommodates frequency dependency yet delivers high computational efficiency.In order to demonstrate the practical worth of the approach, the frequency effect observed with fatigue crack growth in austenitic stainless-steel 304 is analysed. It is found that the crack growth decreases with increasing frequency up to a frequency of 5 Hz after which it levels off. The behaviour, which can be linked to martensitic phase transformation, is shown to be accurately captured by the new model.

Numerical Investigation of Fatigue Behaviours of Non-Patched and Patched Aluminium Pipes

“…In addition, in case of three different patches for each crack length, a total of 15 different modelings was performed using the mechanical values given in Table 1, Table 2 and Table 3, and then numerical analyzes were carried out. In analysis, elasticity module, shear stress and poisson's ratio were introduced to the system respectively, and mesh operation was performed by selecting the mesh structure [23][24][25][26][27][28]. Then, fatigue analyzes of patched and non-patched pipes were carried out according to five different crack parameters.…”

Optimum design and selection of wire rope for hot rolling shop applications

“…Sadeghi et al [29] analyze the effect of high-rate loading of tubes using finite-similitude approach. Salih et al [30] present effects of loading frequency on fatigue crack growth in austenitic stainless-steel 304. Fretting fatigue causes surface defect and consequently, a stress concentration site form [31].…”

Material damage integration approach for efficient modelling of high cycle fatigue

“…It is in fact a common concept to adopt the fatigue damage as the primary basis for computing an accelerated fatigue damage, and less attention is paid to the prevailing constitutive relationship of the fatigue damage to the interface deformations. Another technique to extrapolate damage under cyclic loading was developed by Salih et al (2018) and Salih et al (2019) whereby a linear function of the irrecoverable interface separation, the main fatigue damage determinant, is linearly extrapolated. Even though the technique extrapolated the interface separation as opposed to damage directly, the benefit of respecting the associated constitutive relationship of the fatigue damage evolution during the damage acceleration has not been considered.…”