Computational modelling of shaped metal deposition
Computational modelling of shaped metal deposition
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DOI：
10.1002/nme.2959
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发表时间：
2011-01
影响因子：
2.9
通讯作者：
Andrés Anca;V. Fachinotti;G. Escobar-Palafox;A. Cardona
中科院分区：
文献类型：
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作者：
Andrés Anca;V. Fachinotti;G. Escobar-Palafox;A. Cardona
成形金属沉积（SMD）是一种新型的快速成型工艺，它采用钨极惰性气体（TIG）焊接，在惰性气体室中由机器人控制，通过连续层沉积来制造零件。这一过程可以通过建模和控制得到加强。工业界有兴趣开发系统化的模型来解释观察到的现象，并预测工艺规划和优化的加工条件。在这项工作中，热和机械有限元（FE）建模的SMD。热问题的解决与线性四面体有限有限元，考虑到液/固相变现象。力学问题用六面体单元求解，位移采用三线性插值，平均应力采用常数插值（Q1- P0）。特殊的技术，以占材料添加开发，基于激活/失活的FE。通过数值试验确定了热源模型参数。开发了使用Ti-6Al-4V材料的实验以验证配方。该测试包括TIG清洗程序（电弧通过而不送丝以预热板），然后是单个焊接层。计算结果，包括温度和残余位移，与有限元法（FEM）代码得到的结果进行了比较。最后给出了一个多层SMD的数值算例。版权所有© 2010约翰威利父子有限公司.
Shaped metal deposition (SMD) is a novel process for rapid prototyping that employs tungsten inert gas (TIG) welding controlled by a robot inside an inert gas chamber to build parts by successive layer deposition. This process can be enhanced through modelling and control. Industries are interested in developing systematized models to explain observed phenomena and to predict processing conditions for process planning and optimization. In this work, thermal and mechanical finite element (FE) modelling of SMD is presented. The thermal problem is solved with linear tetrahedral finite FEs that take into account the liquid/solid phase change phenomenon. The mechanical problem is solved with hexahedral elements with tri‐linear interpolation of displacements and constant interpolation of mean stresses (Q1– P0). Special techniques to account for material addition were developed, based on activation/deactivation of FEs. Numerical tests were conducted to determine the heat source model parameters. An experiment using Ti‐6Al‐4V material was developed to validate the formulation. The test consisted of a TIG‐wash procedure (arc passing without wire feeding to preheat the plate) followed by a single welding layer. The results, including temperatures and residual displacements, are compared with those obtained with the finite element method (FEM) code. Finally, a multilayer SMD numerical example is presented. Copyright © 2010 John Wiley & Sons, Ltd.