Vibration-buckling tests on heated composite plates

This paper presents an experimental investigation on vibrations of heated composite plates leading to thermal buckling. The tests were performed considering two main goals: the application of the Vibration Correlation Technique for the detection of thermal buckling in composite plates; and the exploration of the frequency variations before and after the occurrence of a mode jump in post-buckling regime. Two test setups were used. The setups shared a low thermal expansion frame, while they differentiate on the type of heating source and mechanical boundary conditions. Two composite plates with layups [30/−30/5/−5]s and [35/−35/10/−10]s were tested. The plates were excited acoustically using a loudspeaker, and the vibration frequencies were monitored and stored using a laser vibrometer. Buckling temperatures were successfully detected using the Vibration Correlation Technique. Frequency changes, potentially related to the mode jumping, were also detected.