CONSTRAINED RATIONAL CUBIC SPLINE AND ITS APPLICATION

In this paper, a kind of rational cubic interpolation function with linear denominator is constructed. The constrained interpolation with constraint on shape of the interpolating curves and on the second-order derivative of the interpolating function is studied by using this interpolation, and as the consequent result, the convex interpolation conditions have been derived.

Application of Dual-blade Stator to Low-speed Ratio Performance Improvement of Torque Converters

With application of the lock-up clutch in the torque converter（TC）, fuel economy is not much determined by its high-speed ratio transmission efficiency. As a benefit, more researches are focused on its low-speed ratio performance so as to improve vehicle gradeability and launching acceleration performance. According to the results of computational fluid dynamics（CFD） analysis, hydrodynamic loss inside the stator cascade accounts for 42% of the total energy loss at stalling speed ratio. It is found that upstream flow with large impingement angle results in boundary layer separation at the leading edge, which aggregates hydrodynamic loss and decreases circular flow rate dramatically at low-speed ratio. In this paper, a dual-blade stator is proposed to suppress the boundary layer separation, which is parameterized by using the non-uniform rational B spline（NURBS） method. The mean camber line and blade profile curve are expressed by a three control points quadratic open NURBS and a cubic closed one respectively. The key design parameters included the slot width and suction side shape of the primary blade are analyzed. The most effective slot width is found to be between 4% and 8% chord length, and the boundary layer separation can be suppressed completely by decreasing distribution of momentum moment at the primary blade and adding it to the leading edge of the secondary blade. As a result, circular flow rate and impeller torque capacity is increased by 17.9% and 9.6% respectively at stalling speed ratio, meanwhile, low-speed ratio efficiency is also improved. Maximum efficiency at high-speed ratio decreases by 0.5%, which can be ignored as the work of lock-up clutch. This research focuses on using the dual-blade stator to optimize low-speed ratio performance of the TC, which is benefit to vehicle power performance.

DEVELOPABLE SURFACE PATCHES BOUNDED BY NURBS CURVES

In this paper we construct developable surface patches which are bounded by two rational or NURBS curves,though the resulting patch is not a rational or NURBS surface in general.This is accomplished by reparameterizing one of the boundary curves.The reparameterization function is the solution of an algebraic equation.For the relevant case of cubic or cubic spline curves,this equation is quartic at most,quadratic if the curves are B´ezier or splines and lie on parallel planes,and hence it may be solved either by standard analytical or numerical methods.

Travellers:Design Collaboration and Digital Media

This paper examines the use of 3D electronic medium as a tool for procuring detailed design information for the Sandridge Bridge Travellers project. The Sandridge Bridge Travellers project required the production of 10 7.5 m of tall × 5 ― 12 m of wide figures under very tight programme and budget constraints. This was achieved through a synthesis of art and engineering, whereby structure and sculpture become one and the same. Traditional procurement routes would have entailed the production and interpretation of drawings and design details at all discipline interfaces before fabrication; an approach that was unfeasible given the constraints. Instead, The Travellers project saw a single electronic file pass backwards and forwards from client to architect, engineer, and fabricator, with information from the initial artistic concept work phases through to analysis, design, member scheduling and fabrication all integrated and facilitated by a single electronic medium. Key to the delivery was the use of 3D modeling and scripting programs that enabled the efficient use and development of design information through all stages of the design process. This enabled total integration of all trades requiring a collaborative approach where each party maintained joint ownership of the 3D design information from inception to conception.