Theoretical approach to predict transverse impact on variable stiffness curved composite plates.

Abstract

Composite materials are widely used in the industry nowadays due to its attractive advantages such as been lightweight, high strength to weight ratios and ability to design and manufacture complex shapes. However, one of the main disadvantages are that composites are susceptible to impact damage and this is an issue that needs to be addressed. The main interests in this research lies in the analysis of curved variable stiffness composite plates under low velocity impact conditions. There is a need to develop a detailed analytical model to predict the low velocity transverse impact of curved variable stiffness panels. An analytical model is a useful tool in obtaining an initial understanding of the behaviour of such structures under impact loading due its efficient and cost effective nature. Analytical models do not usually require high computational processing power when compared to advanced numerical models and therefore is a time-saving technique. The proposed analytical model would be useful for the composite modelling and manufacturing industry since it is robust, efficient and cost effective when compared with experimental tests or numerical models. The major research gap identified was the need to contribute to the research on analytical modelling of curved composite shell structures and extend the study to sandwich structures as well. The main novelty and contribution of the present research is the development of an analytical model to study impact response of variable stiffness curved composite plates and sandwich plates. The result of the work can be used as a tool to understand the low velocity impact response of curved composite shell structures, i.e. to study the effect of various parameters such as layups, velocities, impact masses, geometry, boundary conditions, etc. affect impact damage response. Analytical methods provide an initial view on the behaviour of a composite structure and the need to build an analytical tool to predict the impact response of variable stiffness composite plates was identified. First order shear deformation theory coupled with two degree of freedom mass-spring system was used to derive analytical force functions for the variable stiffness plate. Contact force histories were plotted to study the effect of geometry, layups and impact velocity on the impact response of variable stiffness curved composite plates.