Density-based topology optimization integrated with genetic algorithm for optimizing formability and bending stiffness of 3D printed CFRP core sandwich sheets
Density-based topology optimization integrated with genetic algorithm for optimizing formability and bending stiffness of 3D printed CFRP core sandwich sheets
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DOI：
10.1016/j.compositesb.2021.109248
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发表时间：
2021-09-02
影响因子：
13.1
通讯作者：
Yanagimoto, Jun
中科院分区：
文献类型：
--
作者：
Zhang, Jingwei;Yanagimoto, Jun
为了将夹芯板的应用范围从传统的2D平板类型扩展到3D复杂形状并同时提高比弯曲刚度，提出了一种新颖的拓扑优化策略，可以在保持良好的成形性的同时优化弯曲刚度。在所提出的方法中，基于密度的拓扑优化与多阶段遗传算法（GA）相结合，以优化夹层板核心结构的可重复单元。采用了两种优化方案，其中一种优化可成形性，另一种优化弯曲刚度，同时满足潜在的失效约束。从理论上推导了核心剪切失效和面屈曲的失效约束，以数学方式表述拓扑优化问题，通过自适应多级遗传算法解决该问题，以增加生成具有物理意义和可增材制造拓扑的可能性。为了对机械性能和成形性进行实验评估，在体积分数约束为 50% 和 62.5% 的情况下，使用碳纤维增强尼龙增材制造了最终的最佳拓扑。对比两种优化方案得到的夹层拓扑结构，芯密度为50%和62.5%的夹层拓扑结构的弯曲刚度分别提高了41.58%和41.49%，吸能能力分别提高了13.60%和29.40%。 L 弯曲和拉拔弯曲测试表明拓扑优化的夹层板的成型性得到改善。所提出的方法能够设计具有改善的弯曲刚度的可成型夹层板，这有望扩大具有更好机械性能的夹层板的应用范围。
To expand the application ranges of sandwich sheets from conventional 2D flat panel types to 3D complex shapes and simultaneously improve the specific bending stiffness, a novel topology optimization strategy that can optimize the bending stiffness while maintaining good formability was proposed. In the proposed approach, the density-based topology optimization was integrated with the multi-stage genetic algorithm (GA) to optimize the repeatable unit cell of the core structure of sandwich sheets. Two optimization schemes were adopted, in which one optimizes the formability and the other one optimizes the bending stiffness while fulfilling potential failure constraints. The failure constraints on core shear failure and face buckling were theoretically deduced to mathematically formulate the topology optimization problem, which was solved by the adaptive multi-stage GA to increase the possibility of generating physically meaningful and additively manufacturable topologies. For the experimental evaluations of mechanical properties and formability, the final optimal topologies under volume fraction constraints of 50% and 62.5% were additively manufactured using carbon fibre reinforced nylon. Comparing the sandwich topologies obtained by two optimization schemes, the bending stiffness of sandwich topologies with the core density of 50% and 62.5% are improved by 41.58% and 41.49%, while the energy absorption capabilities are improved by 13.60% and 29.40% respectively. L-bending and draw-bending tests indicate the improved formability of topologically optimized sandwich sheets. The proposed approach is capable of designing formable sandwich sheets with improved bending stiffness, which is expected to expand the application envelope of sandwich sheets with better mechanical properties.