This study investigates the mechanical behaviour of sandwich panels incorporating orthogonal trapezoidal corrugated cores subjected to uniformly distributed transverse loading. Owing to the inherently three dimensional folded architecture of such cores, accurately predicting their global response poses significant modelling challenges. To address this complexity, a homogenisation based analytical framework is developed by integrating Classical Plate Theory (CPT) with an equivalent orthotropic representation in which the stiffness arises purely from geometry induced anisotropy. The analytical predictions are rigorously validated through detailed finite element simulations in ABAQUS using an isotropic aluminium material model, ensuring consistency between the homogenised assumptions and the numerical reference.

A comprehensive parametric study is performed to quantify the influence of key geometric descriptors—including wave height, crown width, half wave length, core thickness, and face sheet thickness—on global deflection and von Mises stress distribution. The results demonstrate that increasing wave height from 10 to 30 mm reduces maximum deflection by approximately 18%, while a 2 mm increase in face sheet thickness lowers peak stress by nearly 12%. The analytical and numerical responses exhibit excellent agreement, with an average deviation of about 2% within the validated range, thereby establishing a clear and practically useful validity range for the proposed homogenisation approach.

Overall, the findings provide quantitative insight into how orthogonal corrugation geometry governs equivalent stiffness, deformation patterns, and stress behaviour. The developed framework offers a validated, computationally efficient alternative to full 3D modelling and can serve as a practical tool for the preliminary design and optimisation of lightweight corrugated core sandwich structures used in aerospace, marine, and automotive applications.