Field Stress Intensity Calculation of Notched Component Specimens based on Field Intensity Method

doi:10.3901/JME.2018.24.088

Abstract

Abstract: Considering the situation that fatigue life prediction of notched component is an indispensable part in the process of structural design in engineering, it is necessary to solve such problems more effectively by a revised stress field intensity approach. For the existing problems of traditional stress field intensity approach and considering its original assumption, a new model is developed to calculate the field stress intensity, which can take account of the effects of different structure size and load environment. Compared with the contribution of each site in the fatigue damage zone to the peak point in the original field strength method, the new method considers that each point outside the peak in the failure zone has an "impeding effect" on the fatigue damage at the peak and quantitatively analyzes the "impeding effect". The new method also makes a proper correction to parameters of the model, the function form of the weight function and the definition of the fatigue failure zone, and also weaken the influence of the field diameter on the field strength, which consequently makes it overcome the difficult definition of field size parameter in traditional stress field intensity approach and, correspondingly, the field strength have an objective existence of exact solutions. In addition, considering the characteristics of the stress distribution near the notch and its vicinity, the integral form of the original field strength method is improved, simplifying the calculation process of the field strength greatly. Finally, experimental data of notched specimens have been calculated by the revised stress field intensity approach and analysis results show that prediction error coefficient of the new model is within 0.24, which can fully meet the practical demand in engineering. The revised model in this paper has more concise calculation process, keeping high-precision in fatigue life prediction at the same time, and also has a high promotion value.

Key words: fatigue failure region, fatigue life, field size parameter, notched component, stress field intensity

CLC Number:

U467

ZHAO Bingfeng, XIE Liyang, ZHAO Zhiqiang, SONG Jiaxin. Field Stress Intensity Calculation of Notched Component Specimens based on Field Intensity Method[J]. Journal of Mechanical Engineering, 2018, 54(24): 88-97.

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