Design optimisation of hollow box pultruded FRP profiles using mixed integer constrained Genetic algorithm. (15th December 2022)

• Record Type: Journal Article
• Authors: Alhawamdeh, Mohammad; Alajarmeh, Omar; Aravinthan, Thiru; Shelley, Tristan; Schubel, Peter; Mohammed, Ali; Zeng, Xuesen
• Is Part Of: Composite structures. Volume 302(2022)
• Publication Date: 2022-12-15
• Subjects: Hollow box FRP profile -- Finite element analysis -- Genetic algorithm -- Local buckling -- Geometry and layup optimization; Composite construction -- Periodicals; Composites -- Périodiques; 624.18
• DOI: 10.1016/j.compstruct.2022.116247
• Languages: English
• ISSNs: 0263-8223

Abstract

Highlights: The adjusted FEM approach incorporating geometric imperfections and controlled increment size is an efficient and fast-converging tool. The cost of FRP profiles is effectively reduced under bending compared to compression because of the severity of local buckling under compression. Considering a large inner corner radius in the design is an efficient and economic practice for manufacturing optimised hollow FRP profiles. The implementation of the Kriging model is a robust approach to maximise the data use and map the design space. The generated design chart represents a reliable design tool of box FRP profiles combining all the geometric parameters and their interactions. Abstract: Hollow Pultruded Fibre-Reinforced Polymer (FRP) profiles are increasingly used as structural members in many infrastructure applications. However, there is still a lack of coherent design methodology considering local buckling. This research presents a fast-converging numerical approach combining the Finite Element Modelling (FEM) and the Genetic Algorithm (GA) to design the optimal configuration of the geometry and layup design parameters against local buckling under two separate loading conditions of axial compression and four-point bending. The FEM model was validated experimentally. The mixed-integer constrained optimisation GA code (MI-LXPM) was used to solve the problem. The optimisation objective was to minimise the manufacturing cost per metre of pultrusion while maintaining the same stiffness and strength properties of the control profile. The Kriging model was used to interpolate the design space based on the intermediate optimisation data output and produce a practical design chart linking the profile geometry to the ultimate load capacity. An experimental case study on the design of a hollow rectangular pultruded FRP girder demonstrated the proposed optimisation approach. The new design saved 10.6% of the material cost and enhanced the ultimate strength by 41%.