Multiscale analysis of complex aeronautical structures using robust non-intrusive coupling

Abstract

The multiscale analysis of large composite aeronautical structures involves the development of robust coupling strategies. Among the latter, non-intrusive coupling is attractive, since it is able to consistently connect a global simplified linear model to a local detailed one, using features available in commercial software. Up to now, such coupling methods were still limited to academic situations where global and local meshes are geometrically and/or topologically conforming and of low geometric complexity. To meet the goal of merging a complex non-planar global shell to a local detailed 3D model, an extension of these techniques is proposed to handle meshes of complex shapes that are not only non-matching but also geometrically and topologically non-conforming. The implemented strategy is original and robust: the innovative nature of the approach is to expand the initial local solid model by generating transitional shell meshing. The generated model incorporates two distinct coupling interfaces: (i) non-intrusive global-local coupling and (ii) shell-solid coupling. The multiscale strategy was successfully validated through different numerical experiments using standard Input/Output of a commercial finite element software. In particular, a representative use-case involving a realistic fuselage section of an aircraft was computed.

The embedded isogeometric Kirchhoff–Love shell: From design to shape optimization of non-conforming stiffened multipatch structures

“…The dual interface problem is obtained by the condensation of the problem at the interface. It consists in substituting equation (23) into equation (24). We get:…”

“…Now, the analysis of the non-conforming multipatch structure is done in two main steps: first we solve the interface problem (25), and secondly we deduce the local solutions from equation (23). One can see that these equations involve only local systems.…”

“…However, it is well-known that a single NURBS patch cannot represent large and complex ge-ometries with for example holes and kinks. For instance, we are interested here in stiffened structures which are omnipresent in aeronautics [21][22][23]. These structures are obtained by the assembly of a main part (usually denoted by the skin or the panel) with subparts as stringers and ribs (the stiffeners).…”

Space/time global/local noninvasive coupling strategy: Application to viscoplastic structures

“…The method relies on interface coupling; its formulation and its numerical optimization have first been derived in the case of global linear models and local plasticity [15,14]. A number of other applications and extensions have been proposed: use of XFEM at the local scale [29], the treatment of non-matching interfaces [25], coupling between a global plate model and 3D parts for bolted assemblies [18], geometrically non conforming coupling [19], multiscale time and space computation in explicit dynamic [3] with implementation in Abaqus Explicit for the analysis of delamination under impact [4], non-invasive domain decomposition approach [11]. Mesh refinement based on error estimation may also be cast in the proposed non-intrusive framework [10].…”

A Nitsche-based non-intrusive coupling strategy for global/local isogeometric structural analysis

“…Indeed, we necessarily end up with a structured mesh in a NURBS patch. This unavoidably leads to the overlap of some global knot-span elements to allow for a truly global-mesh independent local region to be incorporated for the modeling of any specific local behaviors (e.g., introduction of a hole [8], of an inclusion [9], crack propagation [10,11], emergence of a plastic zone [12], of local damage [13], modeling of local contact [14], etc). Fig.…”