Failure of single hat-shaped thin-walled tubular composite T-joints under impact loading

Abstract

Abstract This paper presents an experimental and numerical investigation into the failure characteristics of single hat-shaped thin-walled tubular T-joints made of twill-woven carbon fiber reinforced thermoplastic (CFRTP) under impact loading. One flat panel and one hat-shaped shell were prepared via a high temperature and pressure molding process first, and then were joined together via (a) adhesive bonding and (b) hybrid bonding and riveting, to form the T-shaped thin-walled tubular joints. Drop weight impact tests were conducted for the T-joints with three impact velocities. Load-time/displacement curves were measured and four distinct failure modes were identified through analyzing damage images and micrographs. It is noted that the specific energy absorption (SEA) capability increases with impact velocity and can be affected significantly by the deformation of the hat-shaped shell, but appears to be less sensitive to the joining forms. Nonlinear finite element analyses based on selected progressive damage model were conducted to predict the failure and energy absorption characteristics of the T-joints under an impact loading. There exists a good correlation between the simulation and experimental results, which validates the present numerical modeling method.