Multi-fidelity structural reliability analysis with polymorphic uncertainty - application to fatigue lifetime prediction for structures made of metal foam

具有多态不确定性的多保真结构可靠性分析 - 在泡沫金属结构疲劳寿命预测中的应用

• 批准号: 428469142
• 负责人: Professor Dr.-Ing. Carsten Proppe
• 金额: --
• 依托单位: Bereich Dynamik / Mechatronik
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/428469142?language=en
• 关键词: Multi; fidelity; structural; reliability; analysis

The representative volume element for heterogeneous materials such as metal foams can be so large that scale separation does not hold. Therefore, the structural analysis cannot be performed with effective material parameters. In this case, only random fields can be determined which represent bounds of the apparent material parameters; the distribution of the material parameters within these bounds is unknown. The reliability analysis for structures made of such heterogeneous materials must therefore consider p-boxes as input parameters.Methods for reliability analysis with p-boxes are computationally very intensive. In comparison to the already very time-intensive methods for reliability analysis, the solution of the optimization problems in the interval analysis or the variation of the parameters of the distribution function generally adds another iteration loop to the computations and thus increases significantly the computational complexity. Therefore, in order to be able to use these methods in engineering practice, a great challenge is to increase their efficiency.The objective of the project is therefore to develop a suitable efficient method for structural reliability analysis with p-boxes and to apply it to lifetime prediction for structures made of metal foam. A suitable method for structural reliability analysis with p-boxes must take the uncertain dependencies between the input parameters into account. In order to obtain an efficient method for structural reliability analysis with p-boxes, efficient sampling-based methods must be applied; to further increase efficiency, model hierarchies must be introduced into the analysis. Model hierarchies should not only be generated from a single mathematical model by varying a discretization parameter, but should also consider general model classes, whose information contents increase the efficiency by fusion and filtering.The structural reliability analysis method that is to be developed within this project allows for a consideration of aleatory as well as epistemic uncertainty and is by no means limited to structures made of metal foams. It will be used in the design phase and can be used in the early design phase to investigate the influence of the heterogeneous microstructure geometry on the lifespan of the structure, thereby optimizing process parameters in the production of heterogeneous materials such as metal foams. In the final design phase, the method is able to represent realistically the uncertainties of the material parameters resulting from the heterogeneity of the microstructure and thus to determine bounds for the lifetime or the probability of failure of the structure. In particular, the time dependence of the material parameters due to damage of the heterogeneous microstructure is considered.

金属泡沫等非均质材料的代表性体积元素可能太大，以致于尺度分离不成立。因此，无法使用有效的材料参数执行结构分析。在这种情况下，只能确定表示表观材料参数界限的随机场；材料参数在这些界限内的分布是未知的。因此，对于这种非均质材料结构的可靠性分析必须考虑P盒作为输入参数，而用P盒进行可靠性分析的方法计算量很大。与已经非常耗时的可靠性分析方法相比，区间分析中的优化问题的求解或分布函数参数的变化通常会增加计算的另一个迭代循环，从而显著增加计算复杂度。因此，为了能够在工程实践中使用这些方法，提高它们的效率是一个巨大的挑战。因此，本项目的目标是开发一种适用于P-盒结构可靠性分析的有效方法，并将其应用于泡沫金属结构的寿命预测。适用于P盒结构可靠性分析的方法必须考虑输入参数之间的不确定相关性。为了得到一种有效的P盒结构可靠性分析方法，必须采用有效的基于抽样的方法；为了进一步提高效率，必须在分析中引入模型层次结构。模型层次结构不应仅通过改变离散化参数由单个数学模型生成，还应考虑一般模型类，其信息内容通过融合和过滤来提高效率。本项目将开发的结构可靠性分析方法考虑了情感和认知的不确定性，绝不限于由金属泡沫制成的结构。它将用于设计阶段，并可用于早期设计阶段，以研究非均质微结构几何形状对结构寿命的影响，从而优化泡沫金属等非均质材料生产中的工艺参数。在最终设计阶段，该方法能够真实地表示材料参数的不确定性，从而确定结构的寿命或失效概率的界限。特别考虑了非均质微结构损伤引起的材料参数随时间的变化。