Riley Katherine S, Jhon Mark H, Le Ferrand Hortense, Wang Dan, Arrieta Andres F
School of Mechanical Engineering, Purdue University, 585 Purdue Mall, West Lafayette, IN, 47907, USA.
Institute of High Performance Computing (IHPC), Agency for Science, Technology and Research (A*STAR), 1 Fusionopolis Way, #16-16 Connexis, Singapore, 138632, Singapore.
Commun Eng. 2024 Aug 23;3(1):115. doi: 10.1038/s44172-024-00260-x.
Bistability enables adaptive designs with tunable deflections for applications including morphing wings, robotic grippers, and consumer products. Composite laminates may be designed to exhibit bistability due to pre-strains that develop during the processing of the polymer matrix, enabling fast reconfiguration between two stable shapes. Unfortunately, designing bistable laminates is challenging because of their highly nonlinear behavior. Here, we propose the Switching Tunneling Method to address this challenge by alternating between gradient-based local minimization and tunneling search phases, with the enhancement of objective expression switching to improve numerical conditioning. Results demonstrate high effectiveness compared to existing optimizers; the Switching Tunneling Method achieves a 99% success rate in finding all energy minima across general composite layups. Additionally, our method facilitates the inverse design of variable pre-strain fields, enabling bioinspired, positive Gaussian curvatures, which are not possible with conventional pre-strain laminates. Validations through both finite element analysis and 3D printed samples confirm the optimal designs.
双稳态能够实现具有可调挠度的自适应设计，适用于包括变形机翼、机器人夹具和消费产品在内的各种应用。由于在聚合物基体加工过程中产生的预应变，复合材料层压板可设计成具有双稳态，从而能够在两种稳定形状之间快速重新配置。不幸的是，由于双稳态层压板具有高度非线性行为，设计它们具有挑战性。在此，我们提出切换隧穿方法来应对这一挑战，该方法通过在基于梯度的局部最小化和隧穿搜索阶段之间交替进行，并增强目标表达式切换以改善数值条件。结果表明，与现有优化器相比，该方法具有很高的有效性；切换隧穿方法在寻找一般复合材料铺层的所有能量最小值方面成功率达到99%。此外，我们的方法有助于可变预应变场的逆向设计，能够实现受生物启发的正高斯曲率，这是传统预应变层压板无法实现的。通过有限元分析和3D打印样品进行的验证证实了这些优化设计。
