RUI: Plastic Instability and Models of Failure in the Uniaxial Compression of Porous Cylinders

本方案涉及用于确定材料成形性的圆柱体顶锻成形的理论研究。后者通常基于应变准则，该准则不能关联所有观察到的失效模式。Lee博士将在有限元模型中使用基于空洞形核、长大和合并的更现实的多孔塑性来模拟锻造。详细的应力和应变分布历史以及空洞增长的演变将被用来预测失效模式。理论结果将与现有的数值和实验结果进行比较。这样确定的重要材料和工艺变量将被用于预测其他金属成形过程的故障，如锻造、挤压和轧制。虽然年轻，但李博士最有可能在这个以本科生为主的机构成功实现他的研究目标。

This proposal is concerned with a theoretical study on upset forging of cylinders which is used to determine the material formability. The latter is normally based on a strain criterion which cannot correlate all observed failure modes. Dr. Lee will use the more realistic porous plasticity, which is based on void nucleation, growth and coalescence, in a finite element model to simulate upset forging. Detailed histories of stress and strain distributions as well as the evolution of void growth will be used to predict the failure modes. The theoretical results will be evaluated against existing numerical and experimental results. The important material and processing variables thus identified will then be used to predict the failures of other metal-forming processes, such as forging, extrusion and rolling. Although young, Dr. Lee is most likely to succeed in meeting his research objectives at this Predominantly Undergraduate Institution.