Effect of Surface Preparation on the Damage and Fracture Behavior of Carbon Fiber- Reinforced Polymer and Titanium Tubular Adhesive Lap-Joints

Abstract

This work evaluates the bond durability for adhesive tubular lap-joints (TLJs) between titanium and CFRP using static tensile tests. Five different treatment methods are introduced to prepare the surface of the CFRP: (1) sanding, (2) air atmospheric pressure plasma treatment (APPT), (3) as-received, (4) Frekote 710NC to act as contamination, and (5) Frekote 700NC plus air APPT to understand the APPT ability to remove contamination. Characterization of the treated surface is done using X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscope (SEM), and Water Contact Angle (WCA) to examine surface energy. Results show that air APPT produces the lowest WCA compared to the other treatment methods, indicating high surface energy and wettability. When the CFRP surface is prepared by sanding, it causes breakage to the underlying fibers, exposing them to the environment. As a result, asreceived CFRP has better bond strength than when prepared with sanding. This study evaluates the durability of adhesive TLJ and builds a relationship between surface characteristics and performance, providing insight into their behavior and knowledge of optimal surface preparation principles.