INVESTIGATING THE EFFECT OF TEMPERATURE ON WAVE PROPAGATION AND DAMAGE IN COMPOSITE STRUCTURES

Abstract

Multilayered composite structures employed extensively in aerospace, marine, and defense industries are frequently subjected to temperature variations that can significantly alter their mechanical properties, viscoelastic behavior, and wave propagation characteristics. The present study was conducted to comprehensively investigate the influence of temperature on wave propagation and its interaction with nonlinear damage in sandwich composite panels. To accomplish this objective, the Wave Finite Element (WFE) method was utilized in conjunction with experimental measurements obtained via a Thermomechanical Analyzer (TMA), nonlinear modeling based on the element birth/death criterion, and experimental validation using piezoelectric transducers. The results demonstrated that within the glass transition temperature range of the epoxy resin, i.e., between 90 and 110 °C, the torsional wavenumber undergoes variations of up to 30%, and the rate of increase in the reflection coefficient reaches 28% per 50 °C. The WFE method identified the mechanical parameters with a deviation of less than 1%, and the discrepancy between the nonlinear model and the experimental data was less than 6%. The fundamental harmonic reflection coefficients for crack and delamination were found to be 0.76 and 0.19, respectively, with a 62% difference in the average harmonics enabling the classification of damage types. The findings of this research provide a numerical-experimental framework for enhancing the accuracy of Structural Health Monitoring (SHM) systems under varying temperature conditions.