Abstract : The method of direct stiffness is used to determine stress intensity factors for two-dimensional fracture mechanic problems of practical interest. For most problems, the crack opening displacement about three nodal positions away from the crack tip was used to determine the stress intensity factor within a projected accuracy of plus or minus 5%. The requirement of extremely small finite elements in the vicinity of the crack tip is circumvented and the amount of computational effort is reduced. Stress intensity factors obtained by this method include the double cantilever specimen, notched cylinder with internal pressure, edge-notched square plate with prescribed edge displacements, and the tension plate with slanted cracks. (Author)