Simulative prediction of the manufacturing process in wire-arc additive manufacturing (WAAM) (T03#)

添加剂制造对金属加工业的未来发展具有巨大的潜力。特别是，通过个性化结构对低成本半成品进行修改，扩大了制造可能性，增加了小系列产品的灵活性和成本效益。在焊接技术研究领域，目前越来越多地考虑开发用于添加剂制造的GMAW工艺变体(WAAM-焊丝电弧添加剂制造)。这使得直接从熔融金属生产具有不同拓扑结构的金属部件成为可能。这意味着衬底的拓扑结构在工艺过程中由工艺本身决定。因此，有效开发附加型制造链的一个关键是能够对必要的工艺步骤进行数字预先计算的数学模型的可用性。特别是，这需要所使用的焊接过程的基于物理的数值模型。这方面的方法已经存在于接头焊接领域，但尚未转移到结构的添加制造中。这将在拟议的转移项目中用一种新的方法来完成，这有望在未来以合理的计算工作量解决数值问题。在SFB1120中，正在研究气体保护焊熔池流动与所产生的焊缝几何形状之间的关系。到目前为止，熔池流动的流体动力学方程主要是用欧拉方法求解的，其中计算网格离散了整个模拟区域。这种方法特别适合于对传统GMA焊接物理效应的数值研究，其中可以假设焊枪在平板上的线性运动。然而，这种方法遇到了组件几何形状的动态增长的限制，就像WAAM过程中的情况一样。Euler方法中使用的Level-Set或VOF方法也需要对整个空间进行离散化，这导致计算效率低下，特别是对于复杂的组件几何形状，即使使用自适应网格策略也是如此。这与SPH(平滑粒子流体力学)方法不同，在SPH方法中，只离散考虑的材料质量，而不是整个模拟域空间。为了验证SPH方法在味精焊接过程模拟中的适用性，作为SFB1120中的一个伴随项目，启动了一个案例研究，以确认可移植到味精过程。这里描述的项目使迄今为止仅在基础研究领域使用的方法能够转移到工业相关的面向应用的模型领域。

Additive manufacturing holds enormous potential for the future development of the metal processing industry. In particular, the modification of low-cost semi-finished products by individualized structures expands the manufacturing possibilities and increases flexibility and cost-effectiveness in small series. In the field of welding technology research, the development of GMAW process variants for additive manufacturing is currently being increasingly considered (WAAM - wire arc additive manufacturing). This makes it possible to produce metallic components with different topologies directly from the molten metal. It implies that the topology of the substrate is determined during the process by the process itself. A key to the efficient development of an additive manufacturing chain is therefore the availability of mathematical models that enable digital precalculation of the necessary process steps. In particular, this requires a physics-based numerical model of the welding process used. Approaches to this already exist in the field of joint welding, but have not yet been transferred to the additive manufacturing of structures. This will be done in the proposed transfer project with a novel approach, which is expected to solve the numerical problem with reasonable computational effort in the future. In SFB1120, the relationship between molten pool flows during gas metal arc welding and the resulting weld geometry is being researched. So far, the hydrodynamic equations of the molten pool flows have mainly been solved using the Euler approach, where the computational mesh discretizes the entire space of the simulation domain. This approach is particularly well suited for the numerical study of the physical effects of conventional GMA welding, where a linear motion of the torch on a flat plate can be assumed. However, this approach encounters limitations with the dynamic growth of the component geometry, as is the case in the WAAM process. The level-set or VOF methods used in the Euler approach also require the discretization of the entire space, which results in inefficiencies in terms of computational effort, especially for complex component geometries, even when using adaptive meshing strategies. This is contrasted with the SPH approach (smoothed particle hydrodynamics), in which only the considered mass of the material is discretized rather than the entire space of the simulation domain. In order to verify the applicability of the SPH method to the simulation of the MSG welding process, a case study was initiated as an accompaning project within the SFB1120 to confirm transferability to the MSG process. The project described here enables the transfer of the methods, which have so far been used exclusively in the field of basic research, to the field of industrially relevant application-oriented models.