Variation of voids and inter-layer shear strength of advanced polymer-matrix composites at different pressures with high-pressure microwave

Xiaoping Chen,Lihua Zhan,Xintong Wu,Jiayang He,Minghui Huang,Yongwei Pu,Xiwen Chen,Chenglong Guan

doi:10.1177/1558925019863958

Abstract

Due to its rapid and volumetric heating capabilities, microwave heating has been conceived as an alternative cost-effective route for curing advanced polymer-matrix composites. Different curing pressures were applied to the pre-impregnated laminates of advanced polymer-matrix composites in a given high-pressure microwave curing process. The variation of voids’ shapes in the advanced polymer-matrix composites was revealed, and the shear failure mechanism of advanced polymer-matrix composites with different porosity was analyzed. During the shear failure process of the advanced polymer-matrix composites, sounds ceaselessly occur. The experiment results of the optical digital microscopy, the scanning electron microscope, and the inter-laminar shear properties test showed that in high-pressure microwave curing process, pressure was not only the main factor that affects the porosity and the mechanical properties but also influences the bonding strength of the resin and the carbon fiber interface significantly. There is a threshold value for the effect of curing pressure on porosity and inter-laminar shear strength of advanced polymer-matrix composites. The internal relationship among porosity, inter-laminar shear strength, and curing pressure of advanced polymer-matrix composites could be summarized as a piecewise power function.

Highlights

Advanced polymer-matrix composites (APMCs) are widely used in the aerospace industry due to its advantages of light weight, high strength, large rigidity, and excellent elasticity.[1]
Under an identical temperature profile and different curing pressures, a series of carbon fiber– reinforced epoxy resin pre-impregnated laminates were cured by the high-pressure microwave, which revealed the evolution of voids in parts, the effect of pressure on the fiber–resin interface, and the internal relationship between pressure and pores and the mechanical properties of APMC parts
In order to analyze the changes of the inter-laminar shear properties of the APMC parts, which were cured under different curing pressures in the high-pressure microwave curing process, specimens were prepared for each curing pressure condition

Summary

Introduction

Advanced polymer-matrix composites (APMCs) are widely used in the aerospace industry due to its advantages of light weight, high strength, large rigidity, and excellent elasticity.[1]. Under an identical temperature profile and different curing pressures, a series of carbon fiber– reinforced epoxy resin pre-impregnated laminates were cured by the high-pressure microwave, which revealed the evolution of voids in parts, the effect of pressure on the fiber–resin interface, and the internal relationship between pressure and pores and the mechanical properties of APMC parts.

Results

Conclusion