Research Article

Failure mechanism of PMI foam core sandwich beam in bending

¹ Faculty of Vehicle Engineering and Mechanics, Dalian University of Technology, Dalian 116024, China
² School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, 2 George St., Brisbane, QLD 4001, Australia

^* e-mail: wangbo@dlut.edu.cn

Received: 11 December 2015
Accepted: 18 December 2015

Abstract

Polymethacrylimide (PMI) foams have been widely applied in aerospace engineering as the core material of sandwich structures. This paper proposes a modified model to predict the constitutive relation of PMI foams and compares it to existing testing data. The study is then applied to the investigation of the failure mechanism of PMI foam core sandwich beams in bending. Corresponding bending tests were carried out where a complex failure process was observed through a high-speed camera. Numerical model of the foregoing sandwich beam is developed, in which the maximum principal stress criteria is used to predict damage propagation in PMI foam core. Both results from tests and numerical simulation validate the reliability of the theoretical prediction of the failure of PMI foam core sandwich beam using the proposed modified model of PMI foams. This study provides a theoretic tool for the design of sandwich structures with PMI foam core.