Inhomogeneous Plastic Deformation and Change in Surface Profile of Metals and Polymers

本研究包括金属和聚合物的不均匀变形和表面形状变化的实验和分析研究。实验采用触针式表面粗糙度测量仪和扫描电子显微镜，数值模拟采用基于有限元法和非均匀材料模型的方法，以铁为试件，研究了多晶体中晶粒变形与表面粗糙度的关系。将图像处理技术应用于微观非均匀变形的测量。还利用由α相和β相组成的黄铜试样研究了两相金属的变形机制。使用各种商业聚合物来研究塑性变形过程中的表面粗糙化。还通过扫描电子显微镜研究了表面形态的变化，其中使用离子涂布仪将金涂层膜置于聚合物样品上。结果表明，结晶聚合物表面发生了表面粗糙化，而非晶聚合物表面没有发生表面粗糙化现象，采用弹塑性有限元法对非均匀材料大变形过程中的表面粗糙化进行了数值模拟。根据计算结果，讨论了材料不均匀性和表面不稳定性的影响。基于Mooney-Rivlin本构关系对胶料的非均匀变形进行了模拟。

The present study consists of experimental and analytical studies of inhomogeneous deformation and change in surface shape of metals and polymers. The stylus instrument for surface roughness measurement and the scanning electron microscop was used in the experiment, while numerical simulation based on the finite element method and models of inhomogeneous material was employed.Iron specimen were used to study the relation between surface roughness and deformation of grains in polycrystals. The image processing technique was also incorporated in the measurement of microscopic inhomogeneous deformation. Brass specimens composed of alpha-phase and beta-phase were also used to study the mechanism of deformation of two-phase metal. Various commercial polymers were used to study the surface roughening during plastic deformation. The change in surface morphology was also studied by the scanning electron microscope, where the ion-coater instrument was used to put the gold coating film on the polymer specimens. It was found that the surface roughening occurs on the surface of the crystalline polymers, while no surface roughening was observed on the amorphous polymers.Numerical simulation of surface roughening during large plastic deformation of inhomogeneous material was performed with the finite strain version of the elastic-plastic unite element method. The effects of the material inhomogeneity and the surface instability were discussed based on the calculated results. The inhomogeneous deformation of rubber compound was also simulated based on the Mooney-Rivlin constitutive law.