Computer model is developed for non-steady and steady-state process of thin-walled tube extension by the rigid punch with curved profile. Rigid-plastic membrane shell theory with quadratic yield criterion is used. Tub...Computer model is developed for non-steady and steady-state process of thin-walled tube extension by the rigid punch with curved profile. Rigid-plastic membrane shell theory with quadratic yield criterion is used. Tube material normal anisotropy, work hardening, wall thickness variation and friction effects are considered. FORTRAN programs of the model predict distributions of the thickness, meridian stress, yield stress and pressure along curved generator of deformed tube and the tube extension force versus punch displacement relation. Model predictions are correlated with experimental data.展开更多
The classical problem of a round metal tube collapsing in concertina mode when subjected to axial compressive loading has been reexamined both theoretically and experimentally. The model including an eccentricity fa...The classical problem of a round metal tube collapsing in concertina mode when subjected to axial compressive loading has been reexamined both theoretically and experimentally. The model including an eccentricity factor proposed by Wierzbicki et al. and modified by Singace et al. has been taken one step further to obtain the real load-displacement history and to investigate eccentricity effects. The influence of the eccentricity parameter m on the mean crushing load was discussed according to the present analysis. Experiments were carried out to verify the eccentricity effects. The results show that experimental and theo- retical load-displacement curves match perfectly, especially in terms of half wavelength. Unlike previous re- searchs, the results suggest that m is not a fixed value and may affect energy absorption.展开更多
文摘Computer model is developed for non-steady and steady-state process of thin-walled tube extension by the rigid punch with curved profile. Rigid-plastic membrane shell theory with quadratic yield criterion is used. Tube material normal anisotropy, work hardening, wall thickness variation and friction effects are considered. FORTRAN programs of the model predict distributions of the thickness, meridian stress, yield stress and pressure along curved generator of deformed tube and the tube extension force versus punch displacement relation. Model predictions are correlated with experimental data.
基金Supportedby the National Postdoctoral Science Foundation (No.2002-17) and the National Natural Science Foundation of China(No. 50275077)
文摘The classical problem of a round metal tube collapsing in concertina mode when subjected to axial compressive loading has been reexamined both theoretically and experimentally. The model including an eccentricity factor proposed by Wierzbicki et al. and modified by Singace et al. has been taken one step further to obtain the real load-displacement history and to investigate eccentricity effects. The influence of the eccentricity parameter m on the mean crushing load was discussed according to the present analysis. Experiments were carried out to verify the eccentricity effects. The results show that experimental and theo- retical load-displacement curves match perfectly, especially in terms of half wavelength. Unlike previous re- searchs, the results suggest that m is not a fixed value and may affect energy absorption.
