Parametric impact analysis on cylindrical sandwich shells with FML face and functionally graded core using a new shell theory

In this paper, the parametric analysis of the impact on cylindrical sandwich shells with the FML face sheet and functionally graded core using a new shell theory is discussed. In this research, two new, simple and engineering models have been presented to predict the history of the contact force caused by a quasi-static transverse impact by an elastic and isotropic impactor in the shape of a sphere, with a low speed, to a composite cylindrical shell. These two models are the half-sine model (or H-S) and the improved mass and spring model with two degrees of freedom (or IS-M). In the H-S model, the maximum contact force and contact duration have been extracted analytically. In the IS-M model, first the mass and the effective stiffness of the shell at the contact point are calculated analytically, then using the successive method and reaching convergence, the modified contact stiffness is obtained. Validation of the present research results was done by comparing the theoretical and experimental results of other researchers and the results of the ABAQUS software, and a good match has been achieved. The results show that the more accurately the effect of (z/R + 1) terms are calculated, the higher the accuracy of estimating the impact response.