TiNi相变圆柱壳的径向压缩特性实验研究

对不同几何尺寸和边界约束条件的TiNi合金圆柱壳进行了准静态径向压缩实验研究,利用数字摄像和图像处理技术得到了不同位置柱壳的变形特征和应变分布,结果表明,在柱壳表面受压处先出现相变铰,随着名义应变的增大,相变铰将发展成相变铰区;在柱壳表面受拉处出现相变铰,但此处材料先进入马氏体相.当径厚比和边界约束不变时,随着名义应变的增大,柱壳的耗能率和比能不断增加.当名义应变不变时,柱壳的耗能率和比能随边界约束个数的增多而增加,吸能效果更好,随径厚比的增加而减小,吸能效率下降.

Experimental Investigation on Radial Compression Characteristics of TiNi Cylindrical Shell

Quasi-static radial compression responses of TiNi alloy cylindrical shell were experimentally studied with different geometric dimensions and under different boundary constraint conditions in this paper. The deformation characteristics and the strain distribution at different positions on the cylindrical shell were obtained by using digital camera and image processing technique. Results show that phase transformation hinge appears first on the compressed surface of cylindrical shell and then develops into phase transformation region along with the nominal strain increasing. Results also show that phase transformation hinge appears later on the tensile surface of cylindrical shell, but the material here goes into martensite phase first. Keeping the same diameter-thickness ratio and the same boundary constraint condition, the energy dissipation rate and the specific energy of cylindrical shell increase along with the nominal strain increasing. Under the same maximum nominal strain, the energy dissipation rate and specific energy of the cylindrical shell increase with the boundary constraint number increasing and the energy absorption effect of shell become better; but these decrease along with the diameter-thickness ratio increasing, at the same time the energy absorption efficiency decrease.