A composite sandwich panel integrally woven with truss core

• A fabrication technique of composite sandwich panels, TWOS was developed.
• TWOS gives high resistance against face–core debonding.
• Tensile strength of the specimens was governed by properties of face sheets.
• TWOS provided much higher compressive strength and stiffness than Distance fabric.

In this work, a new fabrication technique of composite sandwich panels, named TWOS (Truss WOven Sandwich), was introduced, allowing access to the interior spaces of the cores and giving good resistance against face–core debonding, as well as high compressive and shear strengths. To evaluate the validity of TWOS, analytic solutions for its mechanical properties under compression, tension and shear loadings were derived, and specimens were prepared and tested. The equivalent strengths of the TWOS specimens under compression or shear were governed by the fracture behavior of the struts subjected to longitudinal compression. On the other hand, the equivalent strengths under tension were limited by the debonding which occurred near the face sheets. With consideration of the densities, the TWOS cores showed strengths and elastic moduli comparable to or even higher than those of conventional honeycomb cores, and substantially higher than those of Distance fabric cores and cores fabricated by angled stitching.