EPI International Journal of Engineering
Vol 8 No 1 (2025): Volume 8 Number 1, Februari 2025

Design of Quasi-isotropic Rectangular Plates for Optimizing the Fundamental Mode of Bending Vibration

Yoshihiro Narita (Hokkaido University (Professor Emeritus), Sapporo)



Article Info

Publish Date
09 Apr 2026

Abstract

This study is the first work to demonstrate that quasi-isotropic laminated composite plates can be optimized for bending vibration through appropriate stacking-sequence design. A quasi-isotropic plate is defined as a laminated composite plate exhibiting isotropic in-plane stiffness. Owing to this constraint, such plates have traditionally been excluded from stacking-sequence optimization. The present work clarifies why optimization remains feasible despite the in-plane isotropy requirement and outlines a systematic procedure for maximizing or minimizing the fundamental natural frequency with respect to ply orientation angles while preserving isotropic in-plane behavior. Numerical results are provided for square and rectangular plates under various classical boundary conditions, and the corresponding maximum and minimum fundamental frequencies are identified. In particular, the ratio of maximum to minimum fundamental frequency is evaluated; for example, it reaches 2.17 for a cantilevered quasi-isotropic square plate.

Copyrights © 2025






Journal Info

Abbrev

epiije

Publisher

Subject

Civil Engineering, Building, Construction & Architecture Computer Science & IT Control & Systems Engineering Electrical & Electronics Engineering Engineering

Description

EPI International Journal of Engineering (EPI-IJE) is published and managed by Center of Technology, Faculty of Engineering, University of Hasanuddin (CoT, FoE, UNHAS), Indonesia. The main objective of this international journal is to create publishing opportunities and to disseminate knowledge in ...