Multi-scale probabilistic simulation chain for the continuous modelling of the manufacturing process and the structural behavior of disordered fiber-reinforced injection molded components (MeproSi)

由于对轻质部件的需求不断增加，不仅在航空航天领域，而且在以工业规模大规模生产为主的领域，如汽车行业，不连续纤维增强材料变得越来越重要。用热固性注塑成型的现代长纤维复合材料可能会表现出与铝相似的力学性能。然而，在制造过程中消耗的能源明显较少，进一步改善了二氧化碳足迹。其主要缺点是其随机性、无序性和与工艺相关的微观结构，导致其宏观材料响应不可避免地存在固有的不确定性。这种不确定性是由局部纤维含量、长度和取向分布的不确定性以及成分本身和纤维基质界面的材料响应的不确定性造成的。叠加的是由制造工艺施加的微观结构特性的局部变化。在结构应用中，材料响应中不可避免的不确定性导致过度保守的设计，不必要的大安全裕度，从而导致材料轻量化潜力的次优开发。拟议的项目的目标是预测材料响应中与工艺相关的任意不确定性，以及由此产生的注塑件在使用条件下的结构行为。为此，将在所有相关尺度上沿着工艺链建立一个综合的概率多尺度模拟。起始点是不确定的过程，导致不确定的微观结构，从而产生不确定的结构响应。在概率过程模拟的基础上，将得到局部组织及其控制参数的概率分布。使用概率均匀化过程，获得材料行为的随机描述，为材料响应的随机场表示提供输入。必须定义和实施用于基于在过程模拟中获得的空间变化的随机特性来确定随机场的各个表示的适当策略。通过这种方法，可以从工艺条件出发，综合预测不确定因素对短纤维增强构件结构响应的影响。通过这种方法，材料和结构响应中的固有不确定性变得可以通过计算方法获得和控制。最初的关注点是任意的不确定性。在第二阶段，打算扩展到包括认知不确定性，例如由于测量或建模不准确而引起的不确定性。

Due to the increasing demand for lightweight components not only in aerospace applications but also areas dominated by industrial scale mass production such as the automotive sector, discontinuously fiber reinforced materials gain an increasing importance. Modern long fiber composites manufactured in thermoset injection molding might exhibit similar mechanical properties as aluminum. Nevertheless, distinctively lower amounts of energy are consumed during the manufacturing process, further improving the CO2-footprint. A major shortcoming is their random, disordered and process dependent microstructure, causing an inherent inevitable uncertainty in their macroscopic material response. This uncertainty is caused by the uncertainties in the local fiber content, length and orientation distributions as well as by uncertainties in the material response of the constituents themselves and the fiber matrix interfaces. Superimposed are local variations in the microstructural properties imposed by the manufacturing process. In structural application, the inevitable uncertainty in the material response results in over-conservative designs, unnecessarily large safety margins and thus a suboptimum exploitation of the materials lightweight potential.The objective of the proposed project is a prediction of the process-related aleatoric uncertainties in the material response and the resulting structural behavior of injection molded parts under in-service conditions. For this purpose, an integrated probabilistic multiscale simulation along the process chain on all relevant scales will be established. Starting point is the uncertain process, resulting in an uncertain microstructure and thus an uncertain structural response. Based on a probabilistic process simulation, the local microstructure and the probability distributions of its governing parameters will be derived. Using a probabilistic homogenization procedure, a stochastic description of the material behavior is obtained, providing the input for a random field representation of the material response. Appropriate strategies for determination of individual representations of the random fields based on spatially varying stochastic properties obtained in the process simulation have to be defined and implemented. By this means, the effect of uncertainties on the structural response of short fiber reinforced components can be predicted in an integrated manner, starting from the process conditions. By this means, the inherent uncertainties in the material and structural response become accessible and controllable by computational methods. The initial focus is on aleatoric uncertainties. In a second phase, an extension to include epistemic uncertainty, e.g. from measurement or modelling inaccuracies, is intended.