Abstract

The aim of this paper is to determine the fatigue damage of structures subject to random vibrations generated by Qualmark chamber. In real life, structures are generally subjected to complex multiaxial random load. To determine their fatigue life, many criteria have been elaborated, mostly in time domain. To minimize the computing time, the fatigue damage analysis should be done in the frequency domain. Tests that lead to the failure of the structures are commonly used to determine their weakness. But these tests are sometimes costly. To this end, in this paper an original new numerical model of the Qualmark chamber that leads us to determine the generated excitation at each point of its table is proposed. This model is validated using experimental measurement where adjustment process is proposed. Then, we develop a numerical strategy that leads to determine the multiaxial fatigue damage of structure under random vibrations using Matsubara’s criterion developed in the frequency domain of structures tested with Qualmark chamber. A numerical application of a PCB tested with Qualmark chamber is presented at the end of this paper where fatigue damage is determined at each point using the developed strategy. Boundaries condition of the PCB is then determined using the proposed Qualmark table model.

摘要

本文的目的是确定受 Qualmark 试验室产生的随机振动影响的结构的疲劳损伤。在现实生活中，结构通常承受复杂的多轴随机载荷。为了确定它们的疲劳寿命，制定了许多标准，主要是在时域中。为了尽量减少计算时间，疲劳损伤分析应该在频域进行。导致结构失效的测试通常用于确定它们的弱点。但这些测试有时成本很高。为此，在本文中提出了 Qualmark 腔室的原始新数值模型，该模型使我们能够确定其表中每个点产生的激发。该模型使用实验测量进行了验证，其中提出了调整过程。然后，我们开发了一种数值策略，使用在 Qualmark 试验室测试的结构频域中开发的 Matsubara 标准，确定结构在随机振动下的多轴疲劳损伤。本文末尾介绍了使用 Qualmark 试验箱测试的 PCB 的数值应用，其中使用开发的策略确定了每个点的疲劳损伤。然后使用建议的 Qualmark 表模型确定 PCB 的边界条件。本文末尾介绍了使用 Qualmark 试验箱测试的 PCB 的数值应用，其中使用开发的策略确定了每个点的疲劳损伤。然后使用建议的 Qualmark 表模型确定 PCB 的边界条件。本文末尾介绍了使用 Qualmark 试验箱测试的 PCB 的数值应用，其中使用开发的策略确定了每个点的疲劳损伤。然后使用建议的 Qualmark 表模型确定 PCB 的边界条件。