Development and Application-oriented Validation of a Reliable Smoothed Particle Hydrodynamics Discretization for Solids to describe Friction Stir Welding

用于描述搅拌摩擦焊接的可靠固体平滑粒子流体动力学离散化的开发和面向应用的验证

• 批准号: 388107621
• 负责人: Professor Dr.-Ing. Peter Eberhard
• 金额: --
• 依托单位: Institut für Technische und Numerische Mechanik (ITM)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/388107621?language=en
• 关键词: Development; Application; oriented; Validation; Reliable

This research is a second phase of the project, devoted to the accurate simulation of the friction stir welding (FSW) process by means of the Smoothed Particle Hydrodynamics (SPH) method. FSW is a solid state welding process, which is described by multiple interdependent physical phenomena, including plasticity with high strains and strain rates, inelastic heat generation, friction, and solid state bonding. The SPH discretization method, with its meshless nature, provides a framework, which is capable of dealing with large deformations and various physical effects.In the first phase of the project, a novel physically based material model was developed and implemented in order to provide an improved material behavior description specific for FSW. The issue of the particle orientation was also investigated, resolved and tested, followed by the documentation in form of a publication. As a part of the second package, a research on discretization-error based adaptivity in SPH was conducted, providing an original strategy dealing with particle refinement and coarsening.The overall objective of the second phase of the project developed from the first phase. To achieve a major improvement of the SPH formulation for solids, and by these means not only to provide a precise simulation of FSW, but also to develop a reliable, innovative simulation technique, which is able to deal with the simulation of a wide range of industrial applications. Due to the fact that FSW combines variable characteristics, which are also common for many other industrial processes, it offers a sufficient background for a later transfer of he research results.As the time frame of the preceding project was shortened and did not allow to deal with all the aspects in full, they are translated into this project. Some final improvements of the material model by including precipitation hardening and validation of adaption of the discretization are to be accomplished, as well as the development of a material bonding criterion are to be performed in full. Additionally, during the first part of the project, further areas of research were determined. These include an improved SPH stabilization formulation, extension of the friction model based on material behavior, and enhancement and validation of the thermal behavior model. As a final step, the improved SPH solid formulation will be applied to the FSW process in order to predict the final joined geometry, quality of the weld, and microstructural behavior. The precision of the prediction will be examined through comparison with experiments conducted by the IMWF.

本研究是该项目的第二阶段，致力于通过光滑粒子流体动力学（SPH）方法精确模拟搅拌摩擦焊（FSW）过程。搅拌摩擦焊是一种固态焊接工艺，其由多个相互依赖的物理现象描述，包括具有高应变和应变速率的塑性、非弹性热生成、摩擦和固态结合。SPH离散方法，其无网格的性质，提供了一个框架，这是能够处理大变形和各种物理effects.In项目的第一阶段，一个新的物理为基础的材料模型的开发和实施，以提供一个改进的材料行为描述FSW。还研究、解决和测试了颗粒取向的问题，随后以出版物的形式记录。作为第二阶段的一部分，我们对SPH算法中基于离散误差的自适应性进行了研究，提出了一种新颖的粒子细化和粗化策略。第二阶段的总体目标是在第一阶段的基础上发展起来的。实现固体SPH公式的重大改进，并通过这些手段不仅提供FSW的精确模拟，而且开发可靠的创新模拟技术，能够处理广泛的工业应用的模拟。由于搅拌摩擦焊结合了许多其他工业过程中常见的可变特性，因此它为以后的研究成果转移提供了充分的背景。由于前一个项目的时间缩短，无法全面处理所有方面，因此将其转化为本项目。材料模型的一些最终改进，包括沉淀硬化和离散化的适应性验证，以及材料结合标准的发展将被充分执行。此外，在项目的第一部分，确定了进一步的研究领域。这些措施包括一个改进的SPH稳定配方，扩展的摩擦模型的基础上材料的行为，和增强和验证的热行为模型。作为最后一步，改进的SPH固体配方将被应用到搅拌摩擦焊过程中，以预测最终连接的几何形状，焊缝质量和微观组织行为。预测的精度将通过与IMWF进行的实验进行比较来检查。