Isogeometric analysis: LS-DYNA implementation and comparison with standard finite elements

In the last few years, isogeometric analysis (IGA) has become the object of many scientific researches. It is a new numerical analysis method, based on the usage of the exact geometry representation in analysis environment instead of the common mesh discretization. In the NURBS based IGA, the linear Lagrange polynomials basis function, utilized in FEA, are substituted by non uniform rationals b-splines basis functions, the same used in CAD environment. This new approach, in the future, will lead to a great saving of time and money, considering that the meshing phase can be computationally very expensive, hard to fully automate, error-prone, and it becomes exponentially more time consuming with the growth of the product complexity. In this thesis, after a brief theoretical presentation, different types of NURBS based IGA are performed by means of the commercial software LS-DYNA, in order to assess the state of the art and the limits of the software with this method. Moreover, comparisons with FE analyses are made in order to understand the accuracy of the results and the cpu complexity of equivalent problems. At the end, strong and weak points of the method are presented, based on the issues encountered and on the results produced by the analyses.