A stochastic approach to damage evolution in die-cast zinc alloys

压铸锌合金损伤演化的随机方法

• 批准号: 312867041
• 负责人: Professorin Dr.-Ing. Kerstin Weinberg
• 金额: --
• 依托单位: Department Maschinenbau
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2016
• 资助国家: 德国
• 起止时间: 2015-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/312867041?language=en
• 关键词: stochastic; approach; damage; evolution; die

The goal of the proposed research project is to develop a method for predicting the influence of material damage and mechanical load on the life expectation of a typical industrial component. Exemplarily we consider window hardware made of ZAMAK, a zinc alloy which is typically die-cast and widely used for load-bearing parts. New designs, like large glass facades and hidden pivot architecture, require these parts to be small but safe over a long period of time.In the first funding period we focused on the microstructure of the ZAMAK alloy and studied the evolution of defects as a result of fluctuations and deterministic mechanical stresses.In the advised second funding period we scrutinize the structural response of the die-cast component under effects of distributed defects in the material and of uncertain loading conditions. Despite of the widespread use there are only few reliable data available regarding the long term behavior of ZAMAK components. The very high mechanical properties diminish in the course of the component's life. This motivates us to study the loss of mechanical strength in ZAMAK as a result of distributed defects in the material and of uncertain loading conditions. Especially the misuse of the window components in certain situations and the resulting high stresses under uncertain inputs will be considered in this project. To achieve this we will employ a multi-fidelity sampling-based approach.The general idea of incorporating models with different levels of fidelity is based on the definition of surrogate low-fidelity models. Most of the sampling is then done with these cheap, approximate models. To account for the discrepancy between the low-fidelity and the real, high-fidelity solution, a Bayesian regression is employed on a training sample. Then it is possible to use the correlation to gain a probability of the failure within the high-fidelity model.Summarizing we state that uncertain material properties, environmental effects, perturbations in the production process combined with uncertain loading conditions results in a large variations of limit loads and life-expectation of die-cast ZAMAK components.As the result of this research the decay of ZAMAK's mechanical strength andload carrying capacity will be predicted. Prediction is meant here in the sense that incomplete and uncertain information about the problem is accounted for and that probability distributions or error bars on mean values are provided as simulation results.

拟议的研究项目的目的是开发一种方法，以预测物质损害和机械负载对典型工业组成部分生活期望的影响。示例性的是，我们考虑了由Zamak制成的窗口硬件，Zamak是一种锌合金，通常是压铸，广泛用于承载零件。 New designs, like large glass facades and hidden pivot architecture, require these parts to be small but safe over a long period of time.In the first funding period we focused on the microstructure of the ZAMAK alloy and studied the evolution of defects as a result of fluctuations and deterministic mechanical stresses.In the advised second funding period we scrutinize the structural response of the die-cast component under effects of distributed defects in the material and of不确定的加载条件。尽管使用了广泛的使用，但对于Zamak组件的长期行为，只有很少的可靠数据可用。在组件的生活过程中，非常高的机械性能减少了。这激发了我们研究Zamak机械强度的丧失，这是由于材料中的分布缺陷和不确定的负载条件。在某些情况下，尤其是滥用窗口组件以及在本项目中会考虑不确定投入的高应力。为了实现这一目标，我们将采用一种基于多保真抽样的方法。结合具有不同级别忠诚度的模型的一般思想是基于替代低保真模型的定义。然后，大多数采样都使用这些廉价的近似模型进行。为了说明低保真性与真实，高保真解决方案之间的差异，培训样本中采用了贝叶斯回归。 然后，可以使用相关性来获得高保真模型内失败的可能性。蒙日审查指出，不确定的材料特性，环境效应，生产过程中的扰动与不确定的负载条件相结合，导致限制载荷的巨大变化和Zamak组成部分的生命力，这是Zamak组成部分的范围。在这里的意思是，在这里的意思是说有关该问题的不完整和不确定信息，并且在平均值上以示例值提供了概率分布或错误栏。