Various proportional and nonproportional tension-torsion fatigue tests are conducted on aeronautical material-LY12CZ aluminum alloy. The stress and strain states under tension-torsion loading are analyzed by an elasti...Various proportional and nonproportional tension-torsion fatigue tests are conducted on aeronautical material-LY12CZ aluminum alloy. The stress and strain states under tension-torsion loading are analyzed by an elastic-plastic finite element method. The relation between the orientation of crack propagation and each stress and strain component is investigated. Analytical results are compared with experimental data. Results demonstrate that the fatigue cracks tend to be propagated perpendicular to the direction of the largest principle strains under proportional loading, and grow alone one of the maximum shear strain planes under 45° and 90° out-of-phase loadings.展开更多
Failure analysis of railway draw-hook coupler was carried out.The nondestructive testing method was undertaken on some failed couplers in service to designate critical areas of a coupler.Draw-Hook coupler is used to c...Failure analysis of railway draw-hook coupler was carried out.The nondestructive testing method was undertaken on some failed couplers in service to designate critical areas of a coupler.Draw-Hook coupler is used to connect with the same hook coupler or automatic coupler.The influence of each connection types on the coupler strength in this study was discussed.A numerical stress analysis using FEM was performed,and many approaches including critical plane approach were carried out on fatigue life prediction of coupler under different conditions.The results of the proposed fatigue criterion and fatigue life predictions,as well as static numerical analysis,are validated with experimental results.展开更多
A 2D stress strength interference model (2D-SSIM) considering that the fatigue reliability of engineering structural components has close relationship to load asymmetric ratio and its variability to some extent is put...A 2D stress strength interference model (2D-SSIM) considering that the fatigue reliability of engineering structural components has close relationship to load asymmetric ratio and its variability to some extent is put forward. The principle, geo-metric schematic and limit state equation of this model are presented. Reliability evaluation for a kind of diesel engine crankshaft was made based on this theory, in which multi-axial loading fatigue criteria was employed. Because more important factors, i.e. stress asymmetric ratio and its variability, are considered, it theoretically can make more accurate evaluation for structural com-ponent reliability than the traditional interference model. Correspondingly, a Monte-Carlo Method simulation solution is also given. The computation suggests that this model can yield satisfactory reliability evaluation.展开更多
文摘Various proportional and nonproportional tension-torsion fatigue tests are conducted on aeronautical material-LY12CZ aluminum alloy. The stress and strain states under tension-torsion loading are analyzed by an elastic-plastic finite element method. The relation between the orientation of crack propagation and each stress and strain component is investigated. Analytical results are compared with experimental data. Results demonstrate that the fatigue cracks tend to be propagated perpendicular to the direction of the largest principle strains under proportional loading, and grow alone one of the maximum shear strain planes under 45° and 90° out-of-phase loadings.
文摘Failure analysis of railway draw-hook coupler was carried out.The nondestructive testing method was undertaken on some failed couplers in service to designate critical areas of a coupler.Draw-Hook coupler is used to connect with the same hook coupler or automatic coupler.The influence of each connection types on the coupler strength in this study was discussed.A numerical stress analysis using FEM was performed,and many approaches including critical plane approach were carried out on fatigue life prediction of coupler under different conditions.The results of the proposed fatigue criterion and fatigue life predictions,as well as static numerical analysis,are validated with experimental results.
文摘A 2D stress strength interference model (2D-SSIM) considering that the fatigue reliability of engineering structural components has close relationship to load asymmetric ratio and its variability to some extent is put forward. The principle, geo-metric schematic and limit state equation of this model are presented. Reliability evaluation for a kind of diesel engine crankshaft was made based on this theory, in which multi-axial loading fatigue criteria was employed. Because more important factors, i.e. stress asymmetric ratio and its variability, are considered, it theoretically can make more accurate evaluation for structural com-ponent reliability than the traditional interference model. Correspondingly, a Monte-Carlo Method simulation solution is also given. The computation suggests that this model can yield satisfactory reliability evaluation.
