Application of the finite element method in analyzing plate interaction systems using composite materials in thermal environments

The use of composite materials is widespread in various civil applications, especially in the construction of large billboards. However, when exposed to pressure loads and temperature variations, these materials can experience sagging, deformation, and a reduction in mechanical properties. This study employs the finite element method to analyze these properties and calculate the sag of composite panels under the influence of mechanical loads and temperature changes. The panel elements are constructed using a four-node isoparametric element, each with five degrees of freedom. The numerical results are compared for different scenarios and show that for composite panels with symmetrical structures under uniformly distributed loads, the deformation components of the symmetrical layers are identical. In panels with any structure, the sag on the average plane of the panel in the z-direction is the largest, while the sag in the x and y directions and the rotation angle around the x and y axes are minimal. Additionally, the study finds that as temperature increases, sag decreases, while an increase in the applied load leads to increased sag. Moreover, an increase in the number of layers in the plate decreases the deflection in the z-direction, and a higher fiber product factor results in greater deflection. This analysis is applied to a practical problem involving a billboard measuring 2440 mm × 4880 mm at three locations: the corner, middle edge, and center of the plate. The results are compared with previous studies to validate the reliability of the algorithm and program.