Zhuoqi Wu

Optimisation of crush characteristics of the cylindrical origami structure

This paper introduces an application of progressive collapse deformation structure that is called the Cylindrical Origami Structure (COS), which has the ability to absorb the shock of impact. The geometric analysis of COS is presented first. Then the characteristics of COS are further optimised using the most probable optimisation design. After that, the numerical models of COS are constructed and analyses are performed by using the finite element method. Finally, based on the optimised model, two kinds of subdivision scheme (Loop and Modified Butterfly) are employed to smooth the shape of it.

Surface Construction Based on Quadrilateral Mesh

In this paper, a method of constructing smooth surface based on quadrilateral mesh by using C-curves is presented. Instead of using the conventional basis {t3, t2, t, 1}, C-curves are developed by using the basis {sint, cost, t, 1}. Compared with the traditional cubic curves, C-curves can represent transcendental curves exactly such as the helix and the cycloid. Due to many other merits of C-curves, how to develop C-curves into surface becomes a very important problem. By extending the idea of side-vertex method proposed by Nielson, a method for constructing C1 quadrilateral patches using C-curves is developed. The constructed patches interpolate the positions and the first derivatives of the boundary composite C-curves. Then a smooth surface is consequently derived by simply concatenating those patches.

A method of generating smooth surface using C-curves

A method of constructing piecewise G/sup 1/ continuous spline surface using boundary C-curves is presented. C-curves are developed by the basis (sin t, cos t, t, 1), and it overcomes some shortcomings of the nonuniform rational B-splines (NURBS) model. How to develop C-curve into surface becomes a very important problem. Using the convex combination method proposed by Nielson, a piecewise G/sup 1/ spline triangular surface is constructed by boundary C-curves.