It has been shown recently that the
-version of the finite element method is well suited for the analysis of thin walled three-dimensional continua [
]. However, designing and implementing software for the p-version of FEM is a challenge because of the increased complexity compared to the
-version. In this paper, we present an object-oriented finite element system implemented in Java. It is pointed out how the object-oriented paradigm, suitable design patterns and thorough unit testing can help to develop and maintain a complex engineering application. The basic idea of the software design is to separate generally applicable mathematical concepts, like basis functions and geometrical mappings from concrete element formulations that contain the physics of the actual problem. In the mathematical package, there are interfaces representing the concepts of basis functions (forming an Ansatz space) and functions defined on
. Several concrete classes implement these basic interfaces and realize for instance Lagrangian basis functions, hierarchical basis functions, functions constructed by a linear combination of basis functions or functions constructed by the blending function method. The use of NURBS curves hereby allows for the representation of complex geometries like that of the shell structure shown below. The power of this approach lies in the fact that on the element level only the interface types are used. Thus, an element formulation solely contains the physics and is not limited to a certain type of Ansatz space. Also, new Ansatz spaces can be easily incorporated lateron. Generally Java is considered as being slow for numerically intense applications. On the other side there are many advantages that make Java attractive also for simulation software [
]. In this paper, a hybrid approach is presented where the overall program is implemented in Java but numerically intense linear algebra operations are delegated to native code. In the full paper, it is shown that the software can be easily applied to problems involving 75 000 DOFs and more.