A High-Order Composite Plate Element for Mechanical Behavior of Multi-Drive Coupled Dielectric Elastomer Actuator via ANCF

The mechanical model of thin composite structures for the multi-drive actuators in soft robots is difficult to obtain because of the coupling effect of large deformation and large rotation of the multiple dielectric elastomer (DE) driving plates and hyperelastic base structure. In this paper, a new high-order composite plate element is developed to describe the hyperelastic mechanical behavior of the thin DE structures and soft base structure by the absolute nodal coordinate formulation (ANCF). The high-order slope coordinated in the thickness direction of the structures is considered and the high continuity of the composite structure can be ensured. The DE constitutive model and Mooney–Rivlin constitutive model are employed for the composite structure to establish the stiffness and mass matrices of the composite element. The consistent deformation conditions of the interface between multiple DE plates and base structure are derived for the composite element by using a coordinate transformation matrix. The function of the proposed model is verified by comparing with the results of ABAQUS. The problem of displacement continuity between the driven plate and the driving plate can be solved by the high-order continuous ANCF element, and the calculation accuracy and convergence efficiency are obviously improved. The mechanical behavior of a multi-drive coupled DE actuator is studied by considering the different arrangements of driving plates, which is useful for the optimal design and control of DE actuator.