An improved fatigue life model for mechanical components considering load strengthening characteristics

• Published in: Fatigue & fracture of engineering materials & structures Vol. 45; no. 1; pp. 174 - 185
• Main Authors: Liu, Jiazhi, Liu, Xintian, Zhang, Minghui, Wang, Shuci
• Format: Journal Article
• Language: English
• Published: Oxford Wiley Subscription Services, Inc 01.01.2022
• Subjects: Damage; Exponential functions; Fatigue failure; Fatigue life; Fatigue limit; Life prediction; load spectrum; Mathematical models; Mechanical components; Parameter modification; Prediction models; Random loads; Strengthening; strengthening characteristics; swing support rod; two‐dimensional membership function
• ISSN: 8756-758X; 1460-2695
• DOI: 10.1111/ffe.13592

The small load has fuzziness on the strengthening and damage of the component under the action of random fatigue load. This paper introduces the two‐dimensional membership function in fuzzy mathematics to characterize the relationship between stress amplitude, mean value, and damage below the fatigue limit. An exponential function is used to describe the strengthening effect. Under the two‐dimensional load spectrum, the influence of various levels on the component's life is comprehensively considered, and the fatigue life prediction model under random load is proposed. Through the small sample experiment of the car swing support rod, the relevant parameters of the model are obtained. The difference between the modified two‐dimensional and the two‐dimensional load spectrum is compared in fatigue life prediction results. The rules of membership function selection and parameter setting are summarized, and it makes the estimation of component load spectrum life more reasonable.