Influence of layer architecture and constituent selection on the quasi-static and cyclic fracture mechanical behavior of metallic laminate materials.

从实验文献中可知，界面处的材料不均匀性效应对层合金属复合材料（LMC）的疲劳寿命有积极的影响。 另一方面，现有的数值模型可以定量预测裂纹分叉，分层和屏蔽效应的裂纹尖端驱动力附近的个别接口不同的属性。然而，目前不可能预测界面处的不同性质对LMC中的循环裂纹扩展的影响，基于此可以导出定量断裂力学模型描述。本研究项目的总体目标是研究在循环和准循环条件下界面处不同性质对断裂力学行为的不同影响，静态载荷，并确定相应的材料系统，层压结构和加载侧的影响因素，以及相关的金属层压板的损伤机制。此外，在LMCs上的损伤过程中的界面处的增韧机制的效果将通过在独特的GK-REM中的原位实验来确定。在此基础上，分析跨材料模型是开发，考虑到协同作用的各种影响变量的断裂力学行为。基于此模型，将推导出一个优化的层合板设计，并随后进行制造和研究，以验证该模型。重点是不同属性与层状结构的相互作用。的层状结构，如界面密度和层厚度的变化，对断裂力学行为的影响，将系统地研究除了在界面处的弹性模量的强度梯度和梯度的影响。为了研究界面处的不同性质的影响，不同的LMC和双金属将通过ARB工艺专门生产，然后在准静态或循环载荷下对其断裂力学性能进行研究。这使得可以详细了解影响材料力学性能的变量，无论是单独的还是相互结合的，并从中得出优化的材料设计。

It is known from experimental literature that defined material inhomogeneity effects at interfaces can have a positive effect on the fatigue life of laminated metallic composites (LMCs). On the other hand, existing numerical models can quantitatively predict crack bifurcation, delamination and shielding effects of the crack tip driving force near individual interfaces with dissimilar properties. However, it is currently not possible to predict the effects of dissimilar properties at interfaces on cyclic crack propagation in LMCs, based on which a quantitative fracture mechanics model description could be derived.Therefore, the overall objective of this research project is to investigate the different effects of dissimilar properties at interfaces on the fracture mechanical behavior under cyclic as well as under quasi-static loading and to identify the corresponding material system-, laminate architecture- and loading-side influencing factors as well as associated damage mechanisms of metallic laminates. In addition, the effects of toughening mechanisms at interfaces in LMCs on the damage processes will be identified by means of in-situ experiments in the unique GK-REM. On this basis, an analytical cross-material model is to be developed that takes into account the synergetic interaction of the various influencing variables on the fracture mechanical behavior. Based on this model, a fracture-mechanically optimized laminate design will be derived and subsequently manufactured and investigated to validate the model.The focus is on the interaction of dissimilar properties with the lamellar architecture. The influences of the variation of the lamellar architecture, such as the interfacial density and the layer thickness, on the fracture mechanical behavior will be systematically investigated in addition to the effects of strength gradients and gradients in the elastic modulus at the interfaces. In order to investigate the influence of the dissimilar properties at the interfaces, different LMCs and bimetals are to be specifically produced by means of the ARB process, which are then investigated under a quasi-static or cyclic loading with regard to their fracture mechanical properties. This makes it possible to understand the influencing variables on the fracture-mechanical behavior in detail, both in isolation and in combination with each other, and to derive an optimized material design from this.