The book presents the state of the art in isogeometric modeling and shows how the method has advantaged. First an introduction to geometric modeling with NURBS and T-splines is given followed by the implementation into computer software. The implementation in both the FEM and BEM is discussed.
A Primer on Splines and NURBS for Isogeometric Analysis by B. J¨uttler
Extended Isogeometric Analysis for Strong and Weak Discontinuities by V.P. Nguyen and S. Bordas
Boundary Element Methods by G. Beer and B. Marussig
An Introduction to Isogeometric Collocation Methods by A. Reali and T.J.R. Hughes
Isogeometric Analysis Based on T-splines by D.C. Thomas and M.A. Scott
Using T-splines, however, it is possible to overcome the trimming problem by converting a trimmed T-spline into an untrimmed, watertight, analysissuitable T-spline. The details of this process are described in Sederberg et al. (2008). The conversion process first modifies the topology of the T-spline to accommodate any trimming curves. A fitting procedure is then used to match the T-spline surface to the trimming curve. Figure 11d shows the untrimmed T-spline which matches the original trimmed T-spline upon completion of the conversion process. This untrimmed T-spline is now analysissuitable. Additional modeling generates the final bumper geometry shown in Figures 11e and 11f.
The final model of the bumper consists of 876 cubic T-spline shell elements with 705 control points. No intermediate geometry clean-up or meshing step was employed. The free-free eigenvalues were calculated. The calculations were performed directly on the T-spline model in LS-DYNA.