ACCURACY OF COMPOSITE SHELL ELEMENTS IN TRANSIENT ANALYSIS INVOLVING MULTIPLE IMPACTS

The accuracy of composite shell elements in linear transient analysis involving multiple impacts was studied. Results obtained by finite ele ment method and by an analytical solution were compared with each othe r. The previously developed analytical solution for the impact problem was in closed form only until the end of the first contact. In this w ork the solution was extended to multiple impacts in closed form. Ther efore, it was possible to solve problems with several successive impac ts. Comparisons revealed that the composite shell elements of commerci al FEM software give very accurate results for specially orthotropic l aminates in transient analysis involving flexural and shear wave propa gation. The accuracy began to deteriorate in problems where multiple i mpacts occur. Also, it was noticed that commercially available finite element programs may have serious problems in the analysis of composit e structures, for example, in the calculation of stresses.