权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Failure criteria for the prediction of compound journal bearing fatigue - Extension of the methodology considering microstructural effects, Project stage II

复合轴颈轴承疲劳预测的失效标准 - 考虑微观结构效应的方法扩展，项目第二阶段

基本信息

批准号：
233292516
负责人：
Professor Dr.-Ing. Christoph Broeckmann
金额：
--
依托单位：
Institut für Maschinenelemente und Systementwicklung (MSE)
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2013
资助国家：
德国
起止时间：
2012-12-31 至 2020-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/233292516?language=en
关键词：
Failure criteria prediction compound journal

项目摘要

Focus of this project is the description of the fatigue behaviour of white metal alloys in plain bearing applications depending on the microstructure.In the first stage of the project, the local stress state in a compound journal bearing has been calculated by thermo-elastohydrodynamic (TEHD) and finite element (FE) simulations.The multiaxial stress state has been related to the component fatigue strength by means of failure hypotheses. The implemented failure hypotheses require fatigue strength parameters, which have been determined by experiments, for the evaluation of the investigated white metal alloys.As white metals have a heterogeneous microstructure, composed by a ductile solid solution matrix with intermetallic phases causing precipitation hardening, the microstructure has significant influence on the dynamic strength of the material. This influence of the microstructure has been detected in both material and component fatigue tests. Hence, an adequate lifetime prognosis is only possible, if the microstructure of the specimens, from which material parameters are determined to calculate the fatigue limit, is identical to the microstructure in the component to be evaluated. Therefore, the influence of the microstructure on the macroscopic strength will be examined and described in the second project stage.In the field of micromechanics the method of representative volume elements (RVE) is an established and accepted tool for linking microscopic features with macroscopic material properties. In order to calculate RVE, micrographs of white metal are converted into meshed FE models. Regarding the boundary conditions and specific material models of the phases, the RVE is exposed to the operational loads. This is done for different RVE that vary in key parameters such as phase fraction, size and distribution. By the step of homogenization the macroscopic response regarding effective material properties can be derived from material properties of the individual phases. By considering the findings of the mesoscopic simulations and homogenization studies the macroscopic FE model can be adjusted to the local effective material behavior. In this way, the stress state can be calculated as a function of the effective microstructure. Furthermore, key parameters affecting the macroscopic static and dynamic strength can be identified by comprehensive numerical case studies. This is done by correlating stress and strain concentrations in the RVE with external loads, which enables the determination of a damage criterion for composite plain bearings. The validation of the numerical results is done by experimental material and component tests. Ultimately, the results of the individual steps are used to enhance the methodology of lifetime prediction of journal bearings developed in the first project stage by considering effective material parameters as a function of the microstructure.

该项目的重点是根据微观结构描述白色金属合金在滑动轴承应用中的疲劳行为。在该项目的第一阶段，通过热弹流体动力学 (TEHD) 和有限元 (FE) 模拟计算了复合轴颈轴承的局部应力状态。通过失效假设将多轴应力状态与部件疲劳强度相关联。所实施的失效假设需要通过实验确定的疲劳强度参数，以评估所研究的白色金属合金。由于白色金属具有异质微观结构，由延性固溶体基体和引起沉淀硬化的金属间相组成，因此微观结构对材料的动态强度有显着影响。微观结构的这种影响已在材料和部件疲劳测试中得到检测。因此，只有在确定材料参数以计算疲劳极限的样品的微观结构与待评估部件的微观结构相同的情况下，才可能进行充分的寿命预测。因此，微观结构对宏观强度的影响将在项目第二阶段进行检查和描述。在微观力学领域，代表性体积单元方法（RVE）是一种已建立并被接受的工具，用于将微观特征与宏观材料特性联系起来。为了计算 RVE，白色金属的显微照片被转换为网格有限元模型。关于各相的边界条件和特定材料模型，RVE 承受运行载荷。这是针对关键参数（例如相分数、尺寸和分布）不同的不同 RVE 进行的。通过均质化步骤，可以从各个相的材料特性导出有关有效材料特性的宏观响应。通过考虑细观模拟和均质化研究的结果，可以调整宏观有限元模型以适应局部有效材料行为。通过这种方式，可以将应力状态计算为有效微观结构的函数。此外，可以通过综合数值案例研究来确定影响宏观静态和动态强度的关键参数。这是通过将 RVE 中的应力和应变集中与外部载荷相关联来完成的，从而可以确定复合滑动轴承的损坏标准。数值结果的验证是通过实验材料和组件测试来完成的。最终，通过考虑有效材料参数作为微观结构的函数，各个步骤的结果用于增强在项目第一阶段开发的轴颈轴承寿命预测方法。