Title: Hybrid Dovetail Core Joints for Composite Sandwich Structures: Mechanical–Adhesive Splicing for Improved Strength and Toughness

Authors: Rawan Aqel, Patrick Severson, Rani Elhajjar

DOI:

Abstract: Composite sandwich structures are widely deployed in aerospace and transportation because of their high stiffness-to-weight ratio. However, when joining large sections, traditional straight adhesive splices often reduce strength and toughness, creating weak points in otherwise highperformance systems. This work introduces a hybrid dovetail splice that combines adhesive bonding with a mechanical interlock to improve load transfer and joint reliability in carbon fiber/aluminum honeycomb sandwich panels. Two dovetail geometries were fabricated and tested under four-point bending alongside conventional straight splices and control (no splice) specimens. The dovetail design integrates adhesive bonding with a bioinspired mechanical interlock, aiming to reduce stress concentrations at the core/splice interface. Parametric finite element models were also developed to evaluate the influence of dovetail height and angle on normal and shear stresses within the adhesive and core. Experimental results show that dovetail splices can substantially outperform conventional straight joints. Depending on configuration, ultimate strength increased by 13–51% and toughness improved by 2–35%. Dovetail Style A joints achieved the highest load-carrying capacity, while Style B provided superior toughness and energy absorption. The numerical results corroborated the experimental findings, demonstrating stress reductions in the splice material and adhesive/core interface, particularly for dovetails with tenon heights of 15–30 mm and angles of 70°–80°. This hybrid joining strategy demonstrates how mechanical interlocking can complement adhesive bonding to create stronger and more damage-tolerant joints in composite sandwich structures. The approach offers direct relevance to aerospace and transportation applications, where reducing failure risks at splice joints is critical to safety and performance.

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Conference: SAMPE 2026

Publication Date: 2026/04/27

SKU: 140

Pages: 14

Price: $28.00