Approaches to numerical modeling in development process of complex structures for fusion devices

Development of components for fusion device normally comprises numerous simulations to validate their design compatibility with the specified loads according to applicable codes and standards. A strategy of multifield finite element analyses is determined by an iterative nature of design process, and a level of a structure complexity dictates analysis approaches and modeling technique. Nowadays powerful software exploiting the strength of modern computers allows simulating structures in a very detailed way, even for some types of coupled field analyses. As some drawback of this tendency, many efficient numerical tools, used in the past, are not frequently engaged. Sometimes huge numerical resources are spent to solve trivial problems. Direct CAD-analysis meshing of structures in all their complexity may mix effects of different importance and may lead to overlooking some key structure features. Computational problems with convergence in nonlinear analyses often make modeling less flexible to design changes. This paper gives examples of engineering simplified modeling made with clear understanding of an analysis goal and a role of simulations in design process, like for the W7-X stellarator busbar system. Engineering methods to perform multifield analysis including electromagnetic transients for some ITER diagnostics are also presented. An engineering material model to calculate steel superconducting structures working in inelastic range is discussed.