Polyurethane metamaterial vibration isolator with customizable three-directional stiffness using topology optimization and SLS

Abstract Metamaterial vibration isolators can effectively reduce the harm of mechanical vibration to precision instruments and equipment. However, there is limited research on the structural topology optimization of existing metamaterial isolators, and the periodic structure is relatively fixed, making it difficult to achieve personalized design in multiple scenarios. Therefore, based on the principle of variable density topology optimization, this paper proposes a topology optimization design method for a metamaterial isolator with customizable three-dimensional stiffness, and establishes a constitutive model for solid anisotropic material penalty (SAMP), aiming to design a polyurethane metamaterial isolator with adjustable three-dimensional stiffness through topology optimization. The three-dimensional stiffness of the designed unit-cell pattern was simulated and tested through numerical simulation and selective laser sintering (SLS) technology. In addition, we discussed the influence mechanism of anisotropic unit-cell pattern. The simulation results show that the lateral, longitudinal, and vertical stiffness values of the isolator unit pattern are within 10% of the design target, meeting the engineering design requirements of the isolator. The experimental results show that the ratio of elastic moduli in three directions is 5:8:7, indirectly exhibiting anisotropic stiffness characteristics. The unit-cell pattern of the ‘I-beam’ shape effectively meets the anisotropic requirements of triaxial stiffness in isolator applications. This topology optimization method with customizable three-dimensional stiffness can achieve personalized design of metamaterial isolators, and its corresponding hollow structure and additive manufacturing methods also provide technical references for lightweight and high-precision manufacturing of precision machinery.