Combination Resonance Characteristics of a Composite Plate Having Damage Subjected to in-Plane Pulsating Load

The current work predicts the occurrence of combination resonance in parametrically excited, simply supported composite plates with damage throughout the thickness. The damage is anisotropic in nature and parametrically incorporated into the composite using the concept of reduction in stiffness. Finite element is used to obtain the governing differential equation of the plate to which a modal transformation is applied in order to obtain the Matthew-Hill equation. The boundaries of instability due to combination resonance is obtained using a second-order Method of Multiple Scales (MMS) on the Matthew-Hill equation. The present work explores the effect of damage intensity and damage location on the regions of dynamic instability due to combination resonance when a narrow pulsating load having a static and a time-variant sinusoidal component is applied at the edge. Changes in the onset of instability and width of the instability region is observed due to increase in damage intensity and variation in the damage location. Further, the instability regions due to combination resonance effects are comparable to those of simple parametric regions which are usually observed in the literature. This shows that combination resonance effects are important to study the dynamic instability behavior of plate elements.