On the use of finite element programs in structural evaluation and development of design charts

In many phases of structural design and analytical evaluation, the solution of stress and strain distribution in an elastic continuum is required. Special cases of such problems may range from two-dimensional plane stress or plain strain distribution, plate bending to analysis of fully three-dimensional solids. The finite element programs are often used to predict the critical regions for stress analysis and design. Stresses are generally of greater practical importance than displacements for structural design and evaluation. Most of the finite element computer programs calculate element stresses at the centroids, integration points, or nodes of elements. In this paper, examples of bridge deck analysis are used to illustrate the stress interpretation using the finite element programs. It is demonstrated that the stresses at nodes calculated by some finite element programs violate the equilibrium conditions and do not converge to the correct answers. These calculated stresses at nodes are usually too low a...