EXPLICIT UNCONDITIONALLY STABLE APPROACHES FOR BUILT-UP SHELL STRUCTURAL CONFIGURATIONS

Built-up structures, especially those involving shell-type components, are encountered in many areas of engineering. Since full three-dimens ional modeling may be cost prohibitive, shell-type elements have playe d an important role in dynamic simulations; however, the nonlinear dyn amic analysis is still relatively expensive because of the enormous co mputations involved. Most often, implicit approaches such as the Newma rk beta = 0.25 are commonly employed. With the motivation of further e nhancing the accuracy and efficiency of analysis of large practical st ructural problems, we describe explicit, unconditionally stable approa ches newly developed by the authors to analyze the dynamics of linear/ nonlinear shell structures and subsequently show the applicability to large-scale practical structural dynamics problems. The explicit natur e of the formulations and the unconditionally stable algorithmic stabi lity and excellent algorithmic attributes in conjunction with efficien t numerical computational features indeed lend themselves well for the analysis of a wide class of complex shell-type structural configurati ons. The computational and implementation aspects and the numerical ev aluation of the so-called VIP (virtual-pulse) time integral methodolog y that inherits these attributes for general shell-type structural dyn amics problems are presented here. Comparisons are also drawn between the VIP methodology and the Newmark family of methods on the aspects o f the accuracy and computing time. The numerical results given, which were performed on the Gray supercomputer, show the applicability of th e VIP methodology for practical problems, and the computations demonst rate the significant reduction in computing time compared with the mos t widely advocated Newmark family of methods for given accuracy condit ions.