Fatigue life assessment under a complex multiaxial load history: an approach based on damage mechanics
Fatigue life assessment under a complex multiaxial load history: an approach based on damage mechanics
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DOI：
10.1111/j.1460-2695.2011.01600.x
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发表时间：
2012-02
影响因子：
3.7
通讯作者：
R. Brighenti;A. Carpinteri;S. Vantadori
中科院分区：
文献类型：
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作者：
R. Brighenti;A. Carpinteri;S. Vantadori
为了评估复杂（循环或随机）多轴应力历史下结构部件的疲劳行为，可以采用基于损伤力学概念的方法。在本文中，一个模型的疲劳损伤评估的情况下，任意的多轴加载历史的建议，通过使用的耐久性函数，使我们能够确定的损伤累积到材料的最终失败。通过引入耐久函数的演化方程，可以假设最终倒塌发生在损伤D完成时，即D达到1时。该模型采用应力不变量和偏应力不变量来量化损伤现象，其参数是通过遗传算法确定的，一旦被检查的材料的疲劳行为的实验数据是已知的一些复杂的应力历史。与传统的多轴疲劳评估方法相比，该模型具有以下优点：（1）不需要对临界平面进行评估;（2）由于考虑了疲劳载荷历程中的渐进损伤过程，因此不需要使用循环计数算法来确定疲劳寿命;（3）该模型可适用于任何应力历史（单轴循环加载、多轴同相或异相循环加载、单轴或多轴随机加载）。
In order to assess the fatigue behaviour of structural components under a complex (cyclic or random) multiaxial stress history, methods based on damage mechanics concepts can be employed. In this paper, a model for fatigue damage evaluation in the case of an arbitrary multiaxial loading history is proposed by using an endurance function which allows us to determine the damage accumulation up to the final failure of the material. By introducing an evolution equation for the endurance function, the final collapse can be assumed to occur when the damage D is complete, that is when D reaches the unity. The parameters of this model, which adopts the stress invariants and the deviatoric stress invariants to quantify the damage phenomenon, are determined through a Genetic Algorithm once experimental data on the fatigue behaviour of the material being examined are known for some complex stress histories. With respect to traditional approaches to multiaxial fatigue assessment, the proposed model presents the following advantages: (1) the evaluation of a critical plane is not necessary; (2) no cycle counting algorithm to determine the fatigue life is required, because it considers the progressive damage process during the fatigue load history; (3) the model can be applied to any kind of stress history (uniaxial cyclic loading, multiaxial in-phase or out-of-phase cyclic loading, uniaxial or multiaxial random loading).