PrefaceSince the first developments of finite element methods for the analysis of shells, about half a century ago, the possibilities to analyze shells in designs and to study, in general, the behavior of shell structures have vastly increased. However, at the same time as shell finite element procedures were rapidly introduced in many everyday practices of engineering analysis, also, a large research effort was directed towards increasing the capabilities of shell finite element methods, for linear and nonlinear analyses. This research effort is still ongoing because of the great challenges in shell structural analyses. These challenges are largely due to the diversity of shell structural behaviors and the difficulties to solve for such behaviors in a reliable and uniformly effective, ideally optimal, manner. The difficulties are apparent when considering complex shells of arbitrary curvatures, material conditions, boundary supports, loading, and in particular of small thickness. Furthermore, these challenges have grown during the last decades, and probably will continue to grow, because increasingly more daring -but also more beautiful -shell structures have been designed and analyzed than previously thought possible.The earliest studies of shell structures using analytical methods were performed well over a century ago. At that time, and indeed until the development of the finite element method, researchers used all the available physical and mathematical understanding to formulate shell theories and solve shell problems. While the shell theories were quite general in nature, the actual solutions obtained to a shell problem were mostly very approximate, that is, when compared with the actual physical behavior of the shell considered.With the development of the modern finite element method, the approach towards the practical solution of shell problems changed. Finite element procedures were largely developed based on physical understanding without the use of mathematical shell theories. Indeed, various shell finite element methods were proposed by simply superimposing plate bending and plane stress membrane behaviors. With this approach many shell structures were successfully analyzed, but of course only to a certain level of accuracy. In fact, the significant limitations of such element formulations became also apparent and, to some extent, recourse to the use of shell theories was sought to develop more powerful finite element methods.
VI PrefaceThe effective study of shell structures clearly requires a deep physical understanding of shell structural behaviors. The development of more powerful finite element methods requires in addition a strong knowledge of mathematical theories. Indeed, it is clearly the synergy between physical and mathematical understanding that will advance our knowledge of shell structural behaviors and the development of finite element methods. This, in fact, corresponds to the approach taken many years ago in the study of shell structures, but is now a path more difficult to follow. N...