An Automated Structural Optimisation Methodology for Scissor Structures Using a Genetic Algorithm

Abstract

We developed a fully automated multiobjective optimisation framework using genetic algorithms to generate a range of optimal barrel vault scissor structures. Compared to other optimisation methods, genetic algorithms are more robust and efficient when dealing with multiobjective optimisation problems and provide a better view of the search space while reducing the chance to be stuck in a local minimum. The novelty of this work is the application and validation (using metrics) of genetic algorithms for the shape and size optimisation of scissor structures, which has not been done so far for two objectives. We tested the feasibility and capacity of the methodology by optimising a 6 m span barrel vault to weight and compactness and by obtaining optimal solutions in an efficient way using NSGA-II. This paper presents the framework and the results of the case study. The in-depth analysis of the influence of the optimisation variables on the results yields new insights which can help in making choices with regard to the design variables, the constraints, and the number of individuals and generations in order to obtain efficiently a trade-off of optimal solutions.

Computational Design of Bistable Deployable Scissor Structures: Trends and Challenges

“…The maximum deflection is L/100 and the maximum horizontal displacement at any point of the structure is H/100 with L the length and H the height of the structure. This constraint is less strict than for traditional structures [54].…”

“…She developed the concept of the Universal Scissor Component, which can be reconfigured and reused to generate a wide variety of scissor grids [53]. A. Koumar designed a deployable scissor arch that enables quick sheltering solutions for areas struck by disaster [54]. K. Roovers enlarged the spectrum and application possibilities of scissor structures by revealing the mathematical principles required to convert surface geometries into scissor systems [21].…”

“…Finite element models can be used to do a linear analysis of scissor structures in the deployed state subjected to service loads (e.g. wind, snow) [5,54]. A nonlinear analysis of bistable or incompatible scissor structures is required during deployment, subjected to large displacements and geometric incompatibilities [32].…”

“…A. Koumar performed for the first time a multi-objective optimisation of a barrel vault, leading to a pareto front with several optimal solutions. The mass and the compactness were minimised [54].…”

“…3. An analytical verification is implemented for the local buckling of each member by taking into account the normal force and the bending moments around the two axes following Eurocode 9, based on [54]. 4.…”