Manufacturing and Analysis of 3-D Woven Sandwich Composite Under Compressive Loading With Acoustic Emission Monitoring

Abstract

Composite sandwich panel with 3-d woven fabric preform were manufactured through a vacuum assisted resin transfer molding (VARTM) process. The 3-d sandwich fabric preform known as Parabeam, consist of two bi-directional woven E-glass fabric surfaces, which are inter connected mechanically with several vertical woven piles. Parabeam provides a new type of sandwich composite that possess several multifunctional benefits in addition to light weight, bending stiffness and core skin debonding resistance advantages. After consolidation of the panels, polyurethane foam was injected into the core. Conventional sandwich panels were also fabricated with precast polyurethane foam and E-glass face sheet for comparison with the Parabeam sandwich. Edge wise compression tests were conducted and the corresponding acoustic emission (AE) responses were monitored by an advance AE system. Piezoelectric sensor was used to detect the AE signals. On the basis AE signals, the damage source of the specimen were identified, and classified. Furthermore, cracking size were estimated and used to determine the delamination events among the AE signals. Consequently, the AE signals were correlated to the load-displacement curve in the time domain in order to elucidate the types of damage in the specimen. Details of the manufacturing process, the compression tests, and the analysis of the AE signals are presented in this paper.