ABSTRACT
This chapter discusses the main concepts and techniques widely used in the analysis of structures by the finite-element method. The isoparametric formulation is widely used because of its effectiveness and because it allows the elements to have curved shapes. It is used for one, two, and three-dimensional elements. Isoparametric elements can be in the form of a curved bar, a triangular or quadrilateral plate with curved edges, or a three-dimensional brick with curved edges. Finite elements in the form of flat quadrilateral or triangular plates can be used to idealize a shell. In general, the elements will be subjected to in-plane forces and to bending. The element matrices derived separately in earlier sections for elements in a state of plane stress and for bending elements can be combined for a shell element. Idealization of a shell, using curved elements, may be necessary if large elements are employed, particularly in double-curved shells.
