大直径周边切口试件的冲击拉伸试验系统的弹塑性有限元分析

为在旋转盘式间接杆杆型冲击拉伸试验装置上更好地实施起裂止裂试验 ,对采用直径大于杆径的周边切口试件的动态断裂试验系统进行了弹塑性有限元动力学分析 .结果表明 ,尽管试件端面的应力场和位移场是非均匀的 ,但对于深裂纹大直径试件 ,围道J积分仍是守恒的 ,J积分仍可作为裂纹尖端的表征参量 ,且Rice远场J积分公式仍可推广应用 ,但必须对由一维试验原理所得到的试件两端的平均相对位移和载荷进行修正 .为此 ,提出了一种有效的相应修正方法 ,由此得到的远场J积分与动态围道J积分吻合得很好

Elastic-plastic FEA of Tensile Impact Apparatus With a Larger Diameter Circumferentially Notched Specimen

To carry out better crack initiation and crack arrested tests on a self designed bar bar tensile impact apparatus, a specimen is designed with deep circumferential notch and with its external diameter being larger than the bar's . Dynamic elastic plastic FEA of the testing system is performed. Though the stresses and displacements are nonuniform in the end plane of specimen, the results demonstrate that contour J integral is still in conservation and can be regarded as the crack tip characterizing parameter. The formula proposed by Rice is still suitable, but it must be modified for the average opposite displacements and forces in the specimen's end planes, which are obtained with the method based on one dimensional experiment principle. A corresponding modification method is proposed. The Rice's J integrals calculated with the modified method accord well with the contour J integral.