Fatigue performance evaluation of bistable composites at different combinations of loading and environmental conditions
Fatigue performance evaluation of bistable composites at different combinations of loading and environmental conditions
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DOI：
10.1177/00219983231207156
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发表时间：
2023-10
影响因子：
2.9
通讯作者：
Shoab Ahmed Chowdhury;Suyi Li;Oliver Myers
中科院分区：
文献类型：
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作者：
Shoab Ahmed Chowdhury;Suyi Li;Oliver Myers
双稳态复合材料层合板在变形和能量收集结构中具有大规模的应用，但其疲劳性能在很大程度上仍未被探索。本研究调查了刚度和损伤进展，并评估了抗疲劳性能，以制定长期应用的协议。我们分析了位移控制的完全可逆高周疲劳加载对刚度、损伤、曲率和面外加载方向上的卡扣载荷的影响，这些载荷在8种不同的参数组合下进行，频率从1 Hz到10 Hz，两种边界条件，温度从22°C到150°C，循环次数高达300万到1000万次。刚度和损伤演化分析表明，前两个阶段的面外疲劳载荷。该研究提出了一个损伤定义的负载适应两个疲劳损伤模型：（1）Shiri模型和（2）吴模型，而这两个模型表现出合理的准确性，预测损伤的前两个阶段，尽管偏离在最后一个周期，由于假设这个周期作为最终的失效周期。在这两个模型中，Shiri模型提供了较小的模型参数值范围，分别为参数p和q的0.22和0.43，这反映了通过保持适度范围对不同测试条件的可调节性。样品没有遇到纤维断裂的最终故障，并没有失去任何组合的双稳态。曲率和突跳载荷测量值未因疲劳载荷而发生实质性变化。这些发现证实了具有广泛参数范围的应用方案，其中层压板可以在没有显著疲劳损伤的情况下操作，并在无限寿命内保持其抗疲劳性能。
Bistable composite laminates have large-scale applications in morphing and energy-harvesting structures, but their fatigue performance remains largely unexplored. This study investigates the stiffness and damage progression and evaluates bistable performance to develop protocols for long-term applications. We analyze the effects of displacement-controlled fully reversible high cycle fatigue-loading on stiffness, damage, curvature, and snap-through load in the out-of-plane loading direction at eight different combinations of parameters with frequency from 1 to 10 Hz, two boundary conditions, and temperature from 22°C to 150°C up to 3 to 10 million cycles. Stiffness and damage evolution analysis demonstrate the first two stages in out-of-plane fatigue loading. The study proposes a damage definition in terms of load adapting with two fatigue damage models: (1) Shiri Model and (2) Wu Model, while both models exhibit reasonable accuracy in predicting damage for the first two stages despite deviating at the final cycle due to assuming this cycle as the final failure cycle. Of the two models, the Shiri model provided a smaller range of model parameter values, 0.22 and 0.43, for parameters p and q, respectively, which reflects adjustability to different test conditions by maintaining a moderate range. Specimens encountered no final failure by fiber breakage and did not lose bistability for any combination. Curvature and snap-through load measurements have not substantially changed due to fatigue loading. These findings confirm application protocols with a broad range of parameters for which the laminates can operate without significant fatigue damage and maintain their bistable performance for an infinite lifetime.