Jian Deng

Although corrugated composite sandwich structures offer attractive specific stiffness and strength, along with straightforward manufacturability, their in-plane shear performance remains a critical weakness that limits applications under complex loading. To overcome this limitation, a novel origami-inspired N-type (ON) all-composite corrugated core is envisioned, which integrates the geometric features of V-type and I-type substructures. To predict its equivalent shear modulus and ultimate shear strength, an analytical model based on strain energy equivalence is developed, explicitly accounting for distinct deformation mechanisms under both longitudinal (Y-direction) and transverse (X-direction) shear. Upon synthesizing V-type and I-type substructures via an origami-folding approach, ON all-composite corrugated core sandwich specimens are fabricated in a single curing cycle using a modular mold. Tests are subsequently performed under both shear orientations. Numerical simulations with the method of finite elements (FE) are also carried out. Both the experimental and FE results validate the analytical model predictions and reveal a multifaceted performance enhancement. Compared to the traditional V-type core sandwich construction, the ON structure exhibits a 1.42-fold increase in specific stiffness under Y-direction shear; while its strength is interface-sensitive, the model indicates equivalent potential for strength enhancement. Under X-direction shear, the ON structure demonstrates exceptional damage tolerance, achieving a specific energy absorption 4.33 times greater than that of the V-type core, due mainly to the load-redistributing function of its intact I-type substructures. These findings demonstrate that the proposed ON configuration provides a balanced and superior shear performance, making it a promising candidate for advanced lightweight primary structures subjected to complex loadings.