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.

这项研究是该项目的第二阶段，致力于通过平滑粒子流体动力学（SPH）方法精确模拟搅拌摩擦焊（FSW）过程。 FSW 是一种固态焊接工艺，由多种相互依赖的物理现象来描述，包括高应变和应变率的塑性、非弹性发热、摩擦和固态结合。 SPH离散化方法以其无网格特性提供了一个能够处理大变形和各种物理效应的框架。在该项目的第一阶段，开发并实现了一种新颖的基于物理的材料模型，以提供改进了专门针对 FSW 的材料行为描述。还对颗粒取向问题进行了研究、解决和测试，然后以出版物的形式记录下来。作为第二个包的一部分，对SPH中基于离散误差的自适应性进行了研究，提供了处理粒子细化和粗化的原始策略。该项目第二阶段的总体目标是从第一阶段发展而来的。实现固体 SPH 配方的重大改进，通过这些方式不仅提供 FSW 的精确模拟，而且开发可靠、创新的模拟技术，能够处理广泛的模拟工业应用。由于 FSW 结合了许多其他工业过程中常见的可变特征，因此它为后来的研究成果转移提供了足够的背景。由于先前项目的时间框架缩短了，并且不允许处理所有方面都完整后，它们都被转化到这个项目中。通过包括沉淀硬化和离散化适应性验证，将完成材料模型的一些最终改进，并且将全面执行材料粘合标准的开发。此外，在项目的第一部分，还确定了进一步的研究领域。其中包括改进的 SPH 稳定公式、基于材料行为的摩擦模型扩展以及热行为模型的增强和验证。最后一步，改进的 SPH 固体配方将应用于 FSW 工艺，以预测最终的连接几何形状、焊缝质量和微观结构行为。将通过与 IMWF 进行的实验进行比较来检验预测的准确性。