Free Vibration Analysis and Experimental Validation of Sandwich Plates with Hollow Tetrahedral Truss Cores

Abstract

This study investigates the free-vibration behavior of sandwich plates with hollow tetrahedral truss cores and evaluates the capability of an equivalent-continuum model to predict their global natural frequencies. An integrated analytical, numerical, and experimental methodology was adopted. A shear-deformable plate formulation incorporating homogenized core density and stiffness was used to estimate the natural frequencies. Finite element simulations were performed using an equivalent homogeneous-core model. Experimental vibration testing was conducted using impulse-like shaker excitation, and the natural frequencies were identified from acceleration power spectra. The procedure was first evaluated using a homogeneous aluminum plate and subsequently applied to the sandwich plate. For the first three identified sandwich modes, the analytical predictions differed from the experimental frequencies by approximately 0.6%, 2.0%, and 9.5%, respectively, whereas the corresponding finite element discrepancies were approximately 4.5%, 0.6%, and 3.3%. Although the specimen mass increased from 122 to 397 g, the experimental natural frequencies increased by approximately 955.0%, 928.8%, and 602.8%, demonstrating the substantial stiffening effect of the tetrahedral core. The proposed framework provides an efficient means of predicting the lower global vibration modes of hollow lattice-core sandwich plates. Its accuracy decreases for higher modes because local lattice effects are not fully represented by the homogenized analytical model.