Topology optimization for metastructures with quasi-zero stiffness and snap-through features

Publisher:
ELSEVIER SCIENCE SA
Publication Type:
Journal Article
Citation:
Computer Methods in Applied Mechanics and Engineering, 2025, 434
Issue Date:
2025-02-01
Full metadata record
Quasi-zero stiffness (QZS) is highly demanded in passive vibration isolators. Most of the existing design methods of QZS vibration isolators are typically based on mechanism designs, where pre-defined structural configurations, components, or mechanisms with certain features, such as negative stiffness, are required to synthesize the designs. This work introduces topology optimization for QZS structure designs, enabling the design of structures without pre-definitions and resulting in single-part designs rather than structural assemblies. We propose novel mathematical formulations of the objective function based on the QZS force-displacement curve and generic mathematical formulations of the optimization problem. An extended moving isosurface threshold method is used to solve the formulated optimization problem. In addition, topology optimization of metastructures with snap-through features and an alternative design method that synthesizes QZS metastructures by combining snap-through structures with positive stiffness elements are also presented. The optimized snap-through metastructures are numerically validated by nonlinear finite element analysis (NFEA) and experiment, which shows negative stiffness and snap-through characteristics. Numerical examples and investigations are presented for the QZS structures designed by both optimization and synthesis methods. The NFEA results reveal the QZS designs obtained from the two methods can achieve approximately constant stiffness of 0.502 N/mm over a 17 mm displacement range and 0.402 N/mm over a 12 mm displacement range, respectively.
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