金属材料层裂破坏的内聚力模型  

COHESIVE ZONE MODELING OF SPALLATION IN DUCTILE METALS

作　　者：王永刚[1] 胡剑东[1] 王礼立[1] 

机构地区：[1]宁波大学力学与材料研究中心,宁波315211

出　　处：《固体力学学报》2012年第5期465-470,共6页Chinese Journal of Solid Mechanics

基　　金：国家自然科学基金项目(11072119);国家自然科学基金NSAF项目(10876014);国防基础科研计划项目(B1520110003);宁波大学王宽诚幸福基金资助

摘　　要：为了考虑层裂破坏过程中能量耗散行为,论文把内聚力单元嵌入到连续介质有限元单元之间,从而构建了一个层裂破坏的内聚力模型.随后采用该模型对平板撞击条件下的20号钢层裂实验进行了数值模拟研究,重点讨论了内聚力模型特征参数对计算结果的影响规律.研究结果表明采用指数型损伤演化行为的内聚力模型可以较好地描述层裂破坏过程中的能量耗散行为.利用一发实测自由面速度波剖面对计算结果进行校准,确定内聚力模型特征参数.该特征参数可以用于模拟不同撞击速度下的层裂实验,获得的模拟曲线与实验曲线之间符合程度很好,特别是自由面速度"回跳"后波形振荡周期和幅值与实验结果非常接近,这表明了内聚力模型在描述层裂过程中能量耗散行为方面具有较好适用性,并且其参数也具有很好的可移植性.In this work, in order to account for the energy dissipated in the separation of the fracture surfaces during spalling,a cohesive zone model （CZM） has been developed by means of embedding cohesive elements into FEM continuum elements. The proposed numerical model has been used to predict the rear free surface velocity profiles in a flyer plate impact tests on steel under the different impact velocities. The influence of the characteristic CZM parameters on the computed free surface velocity profiles is particularly discussed. The simulation results indicate that the exponential damage evolution of cohesive elements more suitably describes the energy dissipated behavior during spalling. Once calibrated on a reference case, subse- quently using the same parameters of CZM, the predicted free surface velocity profiles under the different impact velocities was found to be in a very good agreement with the experimental data, especially the fre-quency and decay of the free surface velocity oscillations in the later phases of spalling,which demonstrate that the cohesive law shows good applicability and transferability for characterizing the energy dissipated behavior.

关 键 词：层裂 内聚力模型 有限元 自由面速度波剖面 

分 类 号：O346.1[理学—固体力学]