Rezoning and dynamic substructuring techniques in FEM simulations of welding processes
Rezoning and dynamic substructuring techniques in FEM simulations of welding processes
复制标题
焊接过程有限元模拟中的重新分区和动态子结构技术
DOI：
10.1115/1.2901784
复制
发表时间：
1993
期刊：
影响因子：
--
通讯作者：
H. Song
中科院分区：
文献类型：
--
作者：
S. Brown;H. Song
变形和残余应力是大型结构焊接中的突出问题。这些现象的预测将为焊接的设计和制造提供实质性的帮助。遗憾的是，焊接过程中结构相互作用的复杂性和与焊接过程相关的严重非线性限制了焊接模拟的应用。本演示文稿开发了重新分区和动态子结构技术，使大型结构的有限元焊接模拟变得更容易处理。这两种技术都利用了这样一个事实，即焊接过程中只有焊条周围的局部区域是非线性的。因此，作者用密集的有限元网格模拟了电极或热源周围的局部非线性区域。较大结构的其余部分使用较粗的网格和子结构进行建模。然后，递增地重新定义该模型以表示电极在较大结构中的运动。对前一增量的变形几何进行重新定义，实现逐步的热力耦合分析。将这些技术应用于一个二维板焊接实例，实现了模型尺寸的显著减小。计算机内存需求和分析时间实现了接近数量级的减少。三维焊接模拟应该在分析时间上有更大的减少。虽然重新分区和动态子结构技术是为焊接更多的应用而开发的，但它也可以用于其他分析，包括在较大的弹性体内平移一个小的非线性区域。
Distortion and residual stresses cause significant problems in the welding of large structures. Prediction of these phenomena would provide substantial assistance to the design and fabrication of welding. Unfortunately, the complexity of structural interactions during welding and the severe nonlinearities associated with the welding process limit the applications of weld simulations. This presentation develops rezoning and dynamic substructuring techniques that make the finite element welding simulation of large structures more tractable. Both techniques exploit the fact that only a local zone around the welding electrode is nonlinear during welding. The authors therefore model the local nonlinear zone around the electrode or heat source with a dense finite element mesh. The rest of the larger structure is modeled using both a coarser mesh and substructures. The model is then redefined incrementally to represent the motion of the electrode through the larger structure. The redefinition is performed on the deformed geometry of the previous increment, achieving a step-wise coupled thermo-mechanical analysis. The techniques are applied to a two-dimensional plate welding example, achieving significant reductions in model size. Computer memory requirements and analysis times achieve close to order-of-magnitude reductions. Three-dimensional welding simulations should experience greater reductions in analysis time. Although developed for weldingmore » applications, the rezoning and dynamic substructuring techniques can also be used for other analyses involving a small nonlinear zone translating within a larger elastic body.« less