Multi-scale optimisation of thin-walled structures by considering a global/local modelling approach

Abstract

In this work, a design strategy for optimising thin-walled structures based on a global-local finite element (FE) modelling approach is presented. The preliminary design of thin-walled structures can be stated in the form of a constrained non-linear programming problem (CNLPP) involving requirements of different nature intervening at the different scales of the structure. The proposed multi-scale optimisation (MSO) strategy is characterised by two main features. Firstly, the CNLPP is formulated in the most general sense by including all design variables involved at each pertinent scale of the problem. Secondly, two scales (with the related design requirements) are considered: (a) the structure macroscopic scale, where low-fidelity FE models are used and (b) the structure mesoscopic scale (or component level), where more accurate FE models are involved. In particular, the mechanical responses of the structure are evaluated at both global and local scales, avoiding the use of approximated analytical methods. The MSO is here applied to the least-weight design of an aluminium fuselage barrel of a wide-body aircraft. Fully parametric global and local FE models are interfaced with an in-house metaheuristic algorithm. Refined local FE models are created only for critical regions of the structure, automatically detected during the global analysis, and linked to the global one, thanks to the implementation of a sub-modelling approach. The whole process is completely automated, and once set, it does not need any further user intervention.

Multi-scale deterministic optimisation of blended composite structures: case study of a box-wing

“…The GFEM size is of the order of 14000 elements and 50000 degrees of freedom (DOFs). These values have been obtained after a sensitivity analysis of the structural responses to the mesh size (this analysis is not reported here for the sake of brevity but it has been conducted following the same steps presented in [29,50]). Link and shell elements are connected together by node merging.…”

“…It is noteworthy that recently some efforts to formalise and include GL approaches into optimisation frameworks to be used for real complex structures design have been carried out [19][20][21]29].…”

Optimization Design of Mechanical Properties of Frame Plate Structure for Aircraft Repair Based on Genetic Algorithm

“…Michele Iacopo Izzi et al optimized the thin-walled structure of the airframe by the multi-scale optimization method, so that the overall structural weight is minimized without reducing the global stiffness and meet the constraints of the working conditions. [11] Enrico Panettieri et al designed the wing box structures locally and globally with the multi-scale optimization methods, to minimal the weight of the overall structure in the case of meeting the loading condition and fatigue criteria [12].…”

Structural analysis and improvement for a new form traveler in long-span cantilever-casting arch bridge

“…Structural optimization includes performance improvement and weight reduction, which is particularly important in aircraft structure. [23][24][25][26][27][28] This paper, based on the new form traveler adopted in the cantilever construction of Ye-Lang Lake Bridge with a main span of 210 m, aims to improve its structural details and verifies its working performance by carrying out the load test, thus provides useful references for the cantilever casting of similar long-span arch bridges in the future.…”