Geometry Optimization for a Rubber Mount with Desired Stiffness Values in Two Loading Directions Considering Hyperelasticity and Viscoelasticity

Rubber mount is a type of vibration isolator that can absorb vibration and minimize external disturbance. This study proposes an optimization method to design the geometry of a rubber mount to achieve particular stiffness values in two different loading directions. The proposed objective function of the geometry optimization problem is to minimize the error ratios between calculated and target stiffness values in vertical and transverse directions; a weighted sum method is used to combine both error ratios with equal weighting factors. The design variables are the coordinates of some design points which form the cross-section geometry of the rubber mount. A three-dimensional design is then obtained by extrusion of the two-dimensional geometry. Cuckoo search algorithm is used to update the design variables until the objective function value is smaller than a tolerance. Nonlinear finite element analysis is used to estimate the stiffness values of the rubber mount. Both hyperelastic and viscoelastic rubber parameters are numerically identified by fitting to the experimental data. An optimal design of the rubber mount is obtained and prototyped. Experimental tests are performed to validate the design.