Experimental observation of phase transformation front of SMA under impact loading
Pseudoelasticity is one of the main characteristics of shape memory alloys (SMAs), allowing them to recover their initial state after undergoing large deformation. This is due to the martensitictransformation (MT) occurring in the material, turning the austenitic phase into a stress-induced martensitic phase when a mechanical load is experienced. Even if such an effect was largely studied in the past decades under quasi-static loading, the dependence of this effect of the loading rates was rather poorly documented. Only some studies have reported the strain rate dependence of the macroscopic behaviour of SMAs, but no detailed observation of the transformation process under impact loading is available. This paper investigates the influence of the loading rate applied to a NiTi SMA at the level of the MT, providing experimental data of not only the macroscopic stress-strain curves, but also the corresponding observation of the heterogeneous strain field during the test. Main testing results are obtained under tensile loading. Experiments were conducted at three different levels of prescribed velocity : 0.01 mm/s, 1 mm/s and 5000 mm/s, using a classical loading machine for the quasi-static cases and a Split Hopkinson Tensile Bar (SHTB) for the dynamic cases. The observations of the heterogeneous strain field during the tests were made using a digital image correlation (DIC). Additional results under double shear test at various loading rate will be also presented.
Impact testing,Phase transition NiTi shape memory alloy Domain patterns and domain spacing Strain rate
He Huang Dominique Saletti Stephane Pattofatto Feifei Shi Han Zhao
LMT-Cachan,ENS Cachan/CNRS 8535/UPMC,61 Avenue du president Wilson,94235 Cachan cedex,France Laboratoire de Biomécanique,Arts et Métiers ParisTech,151,boulevard de lH(o)pital,75013 Paris,Franc
国际会议
北京
英文
1-9
2013-06-16（万方平台首次上网日期，不代表论文的发表时间）