By expanding the displacement and stress components together with the axial length scale in terms of a small thin shell parameter, three asymptotic shell theories are obtained which incorporate thickness effects in a systematic way. The expansions are made in the equations of linear three‐dimensional elasticity. These theories are used to examine the problem of longitudinal wave propagation in a shell of infinite length.

Results of a preliminary study of stress in bone around dental implants are presented. Stress is calculated using the method of finite elements. Two blade type and one pin type implant are subjected to horizontal and to vertical forces of 19 lb. Differences in blade implant design do not alter the stress distribution significantly. The pin implant shows that most of the load is carried near the entrance into the bone, with a rapid fall in stress.

No abstract

A first approximation theory for the unsymmetric deformation of non- homogeneous, anisotropic, elastic cylindrical shells is derived by means of the asymptotic integration of the elasticity equations. For a homogeneous, isotropic material, the equations reduce to the Donnell equations. The appli cation to a cylinder under combined loading is shown.