Experimental investigation of axial impact buckling response of pseudo-elastic NiTi cylindrical shells

摘要

The axial dynamic buckling responses of pseudo-elastic NiTi alloy cylindrical shells were investigated experimentally for various length/diameter ratios and end constraint conditions by using a modified single pulse SHPB apparatus. The results show that under single pulse axial loading it will first appear the axisymmetrical buckling waviness and then transit into non-axisymmetric buckling mode. This multiple buckling mode and mode transition behavior is possibly due to the wave effect under dynamic loading. The non-axisymmetric buckling patterns are significantly related to the length/diameter ratio and end constraint condition. The initial defect distribution will affect even dominate the non-axisymmetric buckling pattern. It was observed that multiple phase transition hinges (THs) formed in the specimen, which can increase the energy absorption efficiency. The critical buckling threshold and the energy absorption efficiency under impact loading are much greater than that under quasi-static loading. The THs and the dynamic buckling folds are recoverable for NiTi specimens due to the thermo-elastic austenite-martensite phase transition, which differs substantially from the behavior of the conventional elastic-plastic shells.