Evaluating the Influence of <scp>APTES</scp> ‐Treated Glass Powder on Shear and Vibrational Characteristics of Co‐cured Composite Joints

ABSTRACT The co‐cure manufacturing method is widely used to join composite parts, such as fuselage, wings, and ribs, in aerospace applications. This study investigates the effect of 3‐aminopropyl‐triethoxysilane (APTES)‐treated glass powder on the vibrational and shear properties of various joint designs, including single lap joint (SLJ), single strap joint (SSJ), stepped joint (STJ), double lap joint (DLJ), and double strap joint (DSJ). Experimental shear results revealed that the inclusion of APTES‐treated glass powder in joint areas substantially increased the strength of adhesive joints. In particular, SLJ's shear strength with 1 wt.% APTES‐treated glass powder was enhanced by 9.32% compared to untreated SLJ. Further comparisons among various joint designs showed that shear strength increased by 20.79% for DSJ, 14.69% for STJ, 10.43% for DLJ, and 6.24% for SSJ, all compared to SLJ (1 wt.% APTES‐treated glass powder). Particularly, DSJ (1 wt.% APTES‐treated glass powder) exhibited a 51.2 Hz higher natural frequency than other joint designs. Thermogravimetric analysis (TGA) and Fourier transform infrared (FTIR) spectroscopy were conducted to affirm the bonding of APTES to the glass powder. Moreover, a one‐way analysis of variance (ANOVA) affirmed that various joint designs significantly impacted both shear and vibrational performance ( p &lt; 0.05, 95% confidence level).