Development of Analytical and Experimental Technologies for Crystal Morphological Control Fabrication of Hyper-Formability Material

基于晶体塑性的有限元技术揭示了细观材料工程领域在强度和成形性研究方面的巨大进步，并通过计算机模拟(如有限元分析)进一步发展了基于这些晶体控制的制造技术。对于这种用于有限元分析的唯象细观材料模型，需要利用单晶和多晶材料变形的实验观测结果进行参数识别。在本研究中，提出了硬化-软化演化方程，并将其嵌入到弹性/晶态塑性本构方程中。对纯铝单晶在晶向{010}与拉伸轴方向不同的情况下进行了单轴拉伸试验，给出了应力应变关系、滑移线和应变局部化模式。证明了…的数值计算结果。单晶矩形板材拉伸的变形局部化和应变局部化结果与实验结果吻合较好，清楚地解释了各向异性对变形的影响。利用该弹塑性/晶态粘塑性有限元分析工具，结合网格法、单纯形法、扫描单纯形法、模拟退火法和混合法等离散化优化方法，对板材的晶向分布-织构进行了设计。这些系统试图找到超成形的板材。研究了滑移系之间的相互作用对板材应变局部化和成形性的影响。采用Voronoi多边形和面心立方冷轧板材的择优取向织构，模拟了铝板材的这些多晶形态。结果表明，所提出的设计系统找到了具有最佳成形性的最佳取向组合。较少

The crystalline plasticitybased finite element technology revealed the great progress in the field of mesomaterial engineering to study the strength and formability, Further the fabrication technology based on these crystal control has been developed very much by using computer simulation, such like the finite element analyses. For this phenomenological mesomaterial modeling for the finite element analyses, the parameter identification is required by employing the experimental observation results of single and poly crystal material deformations. In this research, the hardening - softening evolution equation has been proposed and embedded in the elastic/crystalline plastic constitutive equation. The uni-axis tension tests of pure aluminum single crystal under the condition of different directions between the crystalline orientation {010} and tensile axis, has provided the stress-strain relationship, slip lines and strain localization patterns. It is demonstrated that the numerical resul … More ts of deformation and strain localization of single crystal rectangular sheet tension shows good agreements with the experimental observations, which elucidate the anisotropic effects on the deformation clearly.This elastic/crystalline viscoplastic finite element analysis tool is also applied to design the crystalline orientation distributions- texture - of the sheet metal in conjunction with the discretized optimization methods, such like the grid method, simplex method, the sweeping simplex method, the simulated annealing method and hybrid method. These system try to find the hyper-formability sheet metal. We investigate how the interaction between the slip-system affects on the strain localization and formability of the sheet. These polycrystalline morphology of aluminum sheet was modeled by employing the Voronoi polygons and the selected orientations - texture - of FCC cold rolled sheet. It demonstrated that the proposed design system found the best combination of selected orientations which has the best formability. Less