Parametric investigation of the effects of cutout geometry, position, number, and depth on the free vibration behavior of sandwich beams

Sandwich beams are widely used in many engineering applications such as aerospace, automotive, marine, and defense industries due to their high stiffness-to-weight ratios and superior mechanical performance. However, cutouts in the beam due to connection elements, weight reduction requirements, maintenance procedures, or damage during service can significantly affect dynamic behavior. In this study, the effects of cutout geometry, cutout position, number of cutouts, and cutout depth on the free vibration behavior of sandwich beams with clamped-free boundary conditions were parametrically investigated using the finite element method. These parameters, which have been addressed together in a limited number of studies in the literature, have been systematically evaluated within the same parametric framework in this study. Three different cutout geometries (circular, square, and triangular) were evaluated in the analysis; the cutout position was modeled at distances of 25, 75, and 125 mm from the clamped end, respectively, and the number of cutouts was modeled as one, two, and three. Furthermore, the effects of shallow and full-depth cutouts on natural frequencies were compared. The developed finite element model was validated against a reference study in the literature, and it was determined that the deviation between the obtained natural frequencies was less than 5%. The results showed that the cutout geometry particularly affects the natural frequencies in higher modes, that the natural frequencies increase with increasing distance of the cutouts from the clamped end to the free end, and that an increase in the number of cutouts leads to a decrease in the natural frequencies. Furthermore, it was determined that the effect of cutout depth varies depending on the cutout position, and that full-depth cutouts in regions close to the free end can increase the natural frequency. These findings comprehensively reveal the effects of cutout parameters on the dynamic behavior of sandwich beams, contributing to the development of sandwich structures designed with vibration performance in mind. © 2026 Taylor & Francis Group, LLC.