Cyclic plastic zone-based notch analysis and damage evolution model for fatigue life prediction of metals

Multiaxial fatigue of the components is a very complex behavior. This analyzes the multiaxial fatigue failure mechanism, reviews and compares the advantages and disadvantages of the classic model. ...

https://journals.sagepub.com/doi/pdf/10.1177/0036850420936220

A novel model for low-cycle multiaxial fatigue life prediction based on the critical plane-damage parameter.

The purpose of this paper is to obtain a more accurate fatigue life of structures by introducing the surface roughness into fatigue life prediction model.,Based on the fatigue life prediction model with surface roughness correction, the shock absorber cylinder is taken as an example to verify the feasibility of the improved method. Based on the load of the shock absorber cylinder during driving, fatigue experiments are performed under longitudinal and lateral forces, respectively. Then, the fatigue life predicted by the modified model is compared with that predicted by the traditional model.,By comparing with the test results, considering the influence of mean stress, the Manson method is more accurate in life prediction. Then, the modified Manson-Coffin and Manson method with surface roughness is more accurate in life prediction under longitudinal force and lateral forces, respectively. This verifies the feasibility of the improved method with the surface roughness.,The research on the influence of surface roughness on fatigue life can lay the technical foundation for the life prediction of products and have great significance to the quality evaluation of products.

An improved fatigue life prediction model for shock absorber cylinder with surface roughness correction

Method for Predicting the Fatigue Life of Geometrically Discontinuous Structures Under Combined Bending and Torsion

Surface and subsurface discontinuities are one of the most important factors affecting the fatigue life of structural cast components. Their location, shape and size varies from component to component, most of them are completely harmless, but one critical defect can lead to in-service failure. Allowable surface discontinuity size finite element (FE)-results can be a practical engineering tool during casting design, process planning and the quality inspection process. Different methods based on the continuum and fracture mechanics applicable on the multiaxial high-cycle fatigue (HCF) and fatigue limit prediction for components with surface discontinuities are compared with experimental results on ISO1083/JS/500-7 nodular cast iron (NCI). Results also confirm, that the fatigue properties of the analyzed material in standards truly represent low-end material strength. A design methodology is presented based on the Defect Stress Gradient approach for the display of an allowable surface discontinuity size FE-result for complex components under proportional loading conditions in HCF.

Ruilong Zhang

Papers

A new method for estimating fatigue life of notched specimen