vibration and buckling behaviour of laminated composite trapezoidal plates with cutout subjected to hygrothermomechanical loading conditions

Abstract

newlineTrapezoidal composite laminates are highly suitable for structural applications in several fields such as aviation, spacecraft, mechanical engineering, and civil engineering. This is primarily attributed to their exceptional stiffness-to-weight ratio and their capacity for versatile design. Trapezoidal laminates have been widely employed in the aircraft and aerospace sectors, in addition to civil engineering applications such as bridge decks, bridge girders, and the reinforcement and retrofitting of pre-existing structures. A comprehensive knowledge of the structural reaction of these materials is necessary due to their intricate usage and practical implications under diverse loading scenarios. This phenomenon is particularly true in the circumstance of vibration and stability response, since the inclusion of in-plane load significantly modifies the natural vibration behavior of structural elements. Indeed, it is assertable for a scenario to arise whereby the fundamental natural frequency of a structural element reaches zero due to a certain magnitude of in-plane stress, thereby leading to instability of said components. Therefore, the issue of dynamic instability holds significant relevance and has been attracting the attention of researcher for a considerable amount of time. newlineThe focusing of this research study is on trapezoidal laminated composite plates with a various cutout sizes and their responses to varied hygrothermal conditions under geometrically (linearly) variable edge loads. To discretized the trapezoidal plate, in this study, a more refined mesh is utilized in proximity to the cutout, while a less refined mesh is employed in regions further faraway from the cutout, a heterosis 9-noded plate elements are used. newlineFree vibrations refer to the natural oscillations or resonances of a structure or material without any external forces applied. Understanding these vibrations is crucial for structural design and stability analysis. Buckling is a failure mode in which a structure