Elastostatic fields in a crack tip neighborhood : measurements and uniqueness

Abstract

Theoretical and experimental investigations of stress and displacement distributions in cracked solids are described. The effect of damaged material in the small highly stressed zone around a crack tip on maximum shear stress trajectories is first shown. Discussed next is experimental work consisting of tensile tests conducted with long retanqular strips of solid propellant clamped along the long edges and containing a central crack; displacements of the strip were obtained through speckle diffraction interferometry. These results are compared to predicted displacements using a finite element technique. Finally, a uniqueness theorem for weak elastostatic traction problems is proved; hypotheses in Kirchoff's uniqueness theorem are relaxed, and uniqueness is proved for a variety of singular problems including the crack problem.