Mechanical Behavior of Crimping Composite Post Insulator: Experimental and Simulation Study

Abstract

The composite post insulator composed of a large diameter mandrel and flange pressed by a one-time integral pultrusion has high strength and good toughness and is widely used in the existing flexible converter valve. For constructing the finite element model of the crimped post insulator, most of the flange surface and the mandrel surface are directly connected, making the simulation model’s stiffness deviate from the actual model and the model distortion. Based on this, this study proposes a new finite element simplified model of crimped composite post insulator based on multi-point constraints (MPC), which accurately simulates the crimping area of mandrel and flange in engineering practice. It verifies the model’s reliability through static tests and characteristic vibration tests. The results show that the difference between the finite element simulation and the test results is within 5%. The finite element modeling method based on MPC local constraints is very reliable in applying crimped composite post insulators. Based on the proposed model, the influence of flange height and thickness on the mechanical properties of composite post insulators is further explored. The results show that the influence of flange height on mechanical properties can be ignored when the height of the insulator stiffener (non-press common area) is constant. Within the allowable thickness range of the flange crimping process, the increase in flange thickness will significantly reduce the maximum bending stress of the insulator and increase its safety margin. It provides a good design idea for the design of crimping composite insulators.