Modal Analysis of Sandwich Structure Using Finite Element Approach

In automotive, aviation, marine and advanced engineering applications, sandwich structures are increasingly preferred due to their superior properties such as high strength to weight ratio, wear resistance, and good surface quality. In this study, the natural frequencies and mode shapes of sandwich structures were investigated, and the effects of different boundary conditions and material combinations on their vibration characteristics were evaluated. Modal analyses were performed using the Finite Element Method (FEM) via ANSYS software, and the generated model was validated by comparing with existing literature data. In the model, carbon steel and carbon fiber reinforced plastic (CFRP) were used as the face sheet materials, while polyurethane elastomer matrix fiber and PVC foam were used as the core material. According to the results, the sandwich structure with a PVC foam core exhibited a 178.6% increase in the first natural frequency compared to the structure with a polyurethane elastomer matrix fiber core. Boundary conditions had a significant impact on natural frequencies, with the completely fixed (C–C–C– C) configuration yielding values 28.6% higher than the completely free (F–F–F–F) condition. Sandwich structures with fully CFRP face sheets showed a 27.7% higher natural frequency than those with hybrid face sheets. These findings demonstrate that the dynamic performance of sandwich structures is highly sensitive to boundary conditions as well as the types of core and face sheet materials, emphasizing the importance of appropriate material and geometric configuration in engineering design.