TY - EJOU AU - Kim, Jihan AU - Kim, Yong Hyup AU - Lee, Sung Won TI - Asymptotic Postbuckling Analysis of Composite and Sandwich Structures via the Assumed Strain Solid Shell Element Formulation T2 - Computer Modeling in Engineering \& Sciences PY - 2004 VL - 6 IS - 3 SN - 1526-1506 AB - The Koiter's asymptotic method is combined with the assumed strain solid shell element formulation for postbuckling analysis of composite and sandwich structures. The assumed strain solid shell element is free of locking and the small angle assumption, and it allows multiple plies through the element thickness. While laminated composite structures are modeled with single element through the thickness, sandwich structures are modeled with three elements stacked through the thickness to model the face sheets and the core independently. The Koiter's method is used to trace initial postbuckling path. Subsequently, the Koiter's method is switched to the arc-length method to investigate postbuckling behavior involving large deflections. The transition point at which the switching occurs is determined using the postbuckling coefficients, obtained from the asymptotic analysis with the fourth order expansion. Numerical tests demonstrate the validity and effectiveness of the present approach. KW - Koiter's method KW - buckling and postbuckling KW - finite element formulation KW - assumed strain solid shell element formulation KW - composite sandwich plates KW - transition point DO - 10.3970/cmes.2004.006.263