Investigation of shear failure load in ultrasonic additive manufacturing of 3D CFRP/Ti structures

Abstract

Abstract Carbon fiber reinforced plastic (CFRP) is an extremely beneficial composite material in the aerospace and automobile industries owing to its high-strength-to-weight ratio, high stiffness, lightweight, and corrosion resistance. However, CFRP material alone is limited in its weight-bearing capabilities. A thin layer material such as Titanium (Ti) is often used along with CFRP laminates to address these issues. Traditional techniques used to join CFRP/Ti stacks include the use of adhesives, glues, or rivets, and bolts. These techniques have several limitations including weight addition, stress cracking, delamination, and limited operating temperatures. These limitations can be readily addressed by the use of solid-state welding techniques based on ultrasonic energy. One such technique is the Ultrasonic Additive Manufacturing (UAM) process, which is capable of fabricating 3D structures of CFRP/Ti laminar composites. Preliminary experimental studies proved the feasibility of using the UAM process to join CFRP/Ti stacks. Further development of this process needs a detailed investigation of the process parameters. This study aims to study the effect of critical process parameters including the ultrasonic energy and pre-surface roughness on the shear strength of the fabricated CFRP/Ti stacks using the UAM process. The study found that both ultrasonic energy and surface roughness have a positive impact on the resulting shear strengths of the UAM fabricated structures.