Harold G. Walters

Evaluation of overhauser splines as boundary elements in linear elastostatics

Abstract The Overhauser spline, which was developed originally for use in geometric modeling, is shown to be an effective and improved element type in the boundary element method for the analysis of linear elastostatics problems. The element is constructed by a linear blending of two parabolic curves; the result is a new form of cubic element in which the end nodes are shared by adjacent elements. C1 continuity between elements is inherently maintained and thus better boundary representations are possible. Examples are presented in which the new element is demonstrated to be a superior performer in comparison with standard Lagrangian linear, quadratic, and cubic elements.

Kinetic Rheology of Hydraulic Fracturing Fluids

Most hydraulic-fracture models assume a steady-state power-law rheology model with only an implied temperature dependence and with no shear-rate history dependence. Newer models attempt to model shear-rate history effects, but still do not accommodate the thermal kinetics of crosslinking and breaking chemistry. A kinetic-rheological model was developed that integrates the nonlinear kinetics of crosslinker chemistry with the in-situ changes in fluid rheology.