USING THE COFFIN EQUATION TO DETERMINE REQUIRED NUMBER OF LOADING CYCLES FOR FATIGUE CRACK GROWTH IN AN IDEAL PLASTIC MATERIAL

Author(s):  
A. P. Shabanov
Author(s):  
Koji Gotoh ◽  
Keisuke Harada

This paper presents the improved numerical simulation of fatigue crack growth considering the crack opening / closing behaviour based on the strip yield model with the stress intensity factor weight function. The mechanical property in the primitive model corresponds to rigid-plastic material and is replaced to the elastic - perfectly plastic material in order to describe the elastic behaviour of material around a crack tip during the unloading process. However, the simulation model based on the elastic - perfect plastic material gives poor growth estimations under rapidly changing of loading histories, e.g. the spike loading. The possibility is pointed out that insufficient considerations of work hardening effect of materials lead the excess crack closure in the numerical simulations. Authors propose the improved numerical simulation fatigue crack growth considering the work hardening effect of materials in this paper. Comparison of proposed simulation results with previous ones and with measured results confirms the primacy of proposed method over previous ones.


2001 ◽  
Vol 11 (PR5) ◽  
pp. Pr5-69-Pr5-75
Author(s):  
V. S. Deshpande ◽  
H. H.M. Cleveringa ◽  
E. Van der Giessen ◽  
A. Needleman

2010 ◽  
Vol 38 (3) ◽  
pp. 194-212 ◽  
Author(s):  
Bastian Näser ◽  
Michael Kaliske ◽  
Will V. Mars

Abstract Fatigue crack growth can occur in elastomeric structures whenever cyclic loading is applied. In order to design robust products, sensitivity to fatigue crack growth must be investigated and minimized. The task has two basic components: (1) to define the material behavior through measurements showing how the crack growth rate depends on conditions that drive the crack, and (2) to compute the conditions experienced by the crack. Important features relevant to the analysis of structures include time-dependent aspects of rubber’s stress-strain behavior (as recently demonstrated via the dwell period effect observed by Harbour et al.), and strain induced crystallization. For the numerical representation, classical fracture mechanical concepts are reviewed and the novel material force approach is introduced. With the material force approach at hand, even dissipative effects of elastomeric materials can be investigated. These complex properties of fatigue crack behavior are illustrated in the context of tire durability simulations as an important field of application.


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