مکانیک هوافضا (Apr 2023)
Experimental Study of the Impact of Interlayer Elastomeric Foam on Failure Pattern of Composite Laminated Panels with Various Layups
Abstract
Achieving methods to improve the failure behavior of composite multilayer plates has always been of interest to researchers. In this article, in order to delay the collapse of composite multilayers in a brittle and sudden manner, a layer of elastomeric foam is inserted between glass-vinyl ester composite plates and the change of the failure pattern and ultimate strength of sandwiched plates with different layering of fibers, compared to single composite plates, is observed. In the examined layers, firstly, the failure pattern was observed in different types of multilayers with different layering including a stronger alignment, orthogonal layering and woven layers under concentrated loading, and the effect of interlayer foam in changing the pattern of rupture hinges in the plates and parameters of bearing capacity and the amount of absorbed energy was observed. Then, a layer of elastomeric foam was placed between the composite plates, which was able to absorb significant energy in the panels before the final collapse by distributing the stress from the upper plate to the lower plate, and delayed the moment of complete rupture. The results showed that the use of interlayer elastomeric foams causes a change in the formation pattern of rupture hinges in the composite panel and significant softening before the final collapse. This increases energy absorption, especially in the case of panels with lower bending stiffness, up to about 115%, which is a satisfactory result.The objective for application of an elastomeric foam was omission of disadvantage by inflexible crushable foams. Although, the elastomeric foam supplied aa lower flexural modulus for the sandwich composite panels due to its lower shear rigidity, it could distribute stress concentration areas from the top to the bottom composite panels, to create a considerable fuselage to reach the ultimate strength via absorption of considerable energy. The results showed promising performance for failure response of elastomeric foam cored sandwich panels. Application of the interlayer elastomeric foam in the case of composite panels with lower stiffness showed larger enhancing effect.
