PPREDICTION OF FREE BOUNDARY IN SOLIDIFICATION ANALYSIS BASED ON INTEGRAL PENALTY METHOD AND ALE CONTROL

为了描述金属中的相变，特别是焊接和凝固，进行了以下研究：1。自由边界问题数值分析基础研究，2.基于所谓的“积分罚分法“的数值代码的开发，以及3。金属焊接过程中相界和热影响区的力学性能.自由边界问题数值分析的基础研究将焊接和凝固过程视为Stefan问题，从空间描述和材料描述两方面建立了控制方程。积分罚函数法将自由面边界处的Stefan条件用积分形式代替，便于数值分析中的真实的应用.基于积分罚函数法的数值计算程序的开发利用积分罚函数法，开发了Stefan问题的有限元计算程序 ...更多信息 惩罚方法数值研究进行澄清之间的稳定性条件的惩罚数，空间步长，和时间增量。通过一个两相/二维问题的计算，验证了该方法的适用性.相界和热影响区的力学性能对SUs 304不锈钢圆板进行了一点焊接工艺，并通过该工艺评估了温度历史。硬度和显微组织都在相边界处显著变化，特别是在温度越过AC 1转变点的热影响区，因此可以从这些试验中识别相边界。对铝板进行焊接工艺，从铝板制备小尺寸试样用于拉伸试验。采用微网格压痕法测量焊缝局部变形。应变分布由网格移动的位移计算。少

In order to describe the phase change in metals, particularly welding and solidification, the following investigations are carried out ; 1. Fundamental study of numerical analysis in free boundary problem, 2. Development of numerical code based on so-called "Integral Penalty Method, " and 3. Mechanical properties of phase boundary and heat affected zone in welding process in metals.1. Fundamental study of numerical analysis in free boundary problem Regarding the welding and solidification processes as the Stefan problem, the governing equations are formulated in terms of spatial description as well as material description. The Stefan condition at the free surface boundary is replaced by the integral form by use of the integral penalty method, and so this method is advantageous for real utilization in numerical analysis.2. Development of numerical code based on the integral penalty method A finite element code for predicting the Stefan problem is developed with reference to the integral … More penalty method. Numerical studies are carried out to clarify the stability condition between the penalty number, the spatial step, and the time increment. A two-phase/two-dimensional problem is also calculated to demonstrate the applicability of the proposed method.3. Mechanical properties of phase boundary and heat affected zone A one point weld processing is performed on a circular plate of SUs304 stainless steel, and the temperature history is evaluated through the process. Both the hardness and the microstructure change remarkably at the phase boundary, particularly at the heat affected zone where the temperature comes across the AC1 transformation point, and so the phase boundary can be identified from these tests. A welding process is performed for an aluminum plate, from which a small size specimen is prepared for a tension test. Microgrid indentation is used to measure the local deformation over the weld. The strain distribution is calculated from the displacement of the movement of the grids. Less