8 research outputs found
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Multi-scale reliability-based design optimisation framework for fibre-reinforced composite laminates
Purpose
The purpose of this study is to enable performing reliability-based design optimisation (RBDO) for a composite component while accounting for several multi-scale uncertainties using a large representative volume element (LRVE). This is achieved using an efficient finite element analysis (FEA)-based multi-scale reliability framework and sequential optimisation strategy.
Design/methodology/approach
An efficient FEA-based multi-scale reliability framework used in this study is extended and combined with a proposed sequential optimisation strategy to produce an efficient, flexible and accurate RBDO framework for fibre-reinforced composite laminate components. The proposed RBDO strategy is demonstrated by finding the optimum design solution for a composite component under the effect of multi-scale uncertainties while meeting a specific stiffness reliability requirement. Performing this using the double-loop approach is computationally expensive because of the number of uncertainties and function evaluations required to assess the reliability. Thus, a sequential optimisation concept is proposed, which starts by finding a deterministic optimum solution, then assesses the reliability and shifts the constraint limit to a safer region. This is repeated until the desired level of reliability is reached. This is followed by a final probabilistic optimisation to reduce the mass further and meet the desired level of stiffness reliability. In addition, the proposed framework uses several surrogate models to replace expensive FE function evaluations during optimisation and reliability analysis. The numerical example is also used to investigate the effect of using different sizes of LRVEs, compared with a single RVE. In future work, other problem-dependent surrogates such as Kriging will be used to allow predicting lower probability of failures with high accuracy.
Findings
The integration of the developed multi-scale reliability framework with the sequential RBDO optimisation strategy is proven computationally feasible, and it is shown that the use of LRVEs leads to less conservative designs compared with the use of single RVE, i.e. up to 3.5% weight reduction in the case of the 1 × 1 RVE optimised component. This is because the LRVE provides a representation of the spatial variability of uncertainties in a composite material while capturing a wider range of uncertainties at each iteration.
Originality/value
Fibre-reinforced composite laminate components designed using reliability and optimisation have been investigated before. Still, they have not previously been combined in a comprehensive multi-scale RBDO. Therefore, this study combines the probabilistic framework with an optimisation strategy to perform multi-scale RBDO and demonstrates its feasibility and efficiency for an fibre reinforced polymer component designUniversity of Aberdeen Elphinstone scholarship scheme
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Jig-less end-effector system for automating exhausting composite fuselage assembly tasks
Collections: Brunel Composite CentreIn this study, the jig-less end-effector system developed to assemble components of a full-scale multifunctional integrated composite thermoplastic lower fuselage section is tested and validated. To offset the environmental impact of higher volume of air transport, the aviation industry wants to design lighter and more environmentally friendly aircraft. To achieve this, there is a need to exploit novel materials and technologies. Advanced thermoplastic composites provide an excellent material option thanks to their weldability, low density, low overall production cost, improved fracture toughness and recyclability. However, to fully appreciate their capabilities and benefits, new manufacturing approaches and techniques are needed. Hence, projects such as TCTool, "innovative tooling, end-effector development and industrialisation for welding of thermoplastic components", aim to develop innovative tooling and end-effector systems for the assembly of a multifunctional thermoplastic fuselage. This study presents the development, operation, and testing of the jig-less end-effector system used in the TCTool project for picking, placing, and temporary welding and fixing fuselage's clips and stringers.This study has received funding from the Clean Sky 2 Joint Undertaking under the European Union's
Horizon 2020 research and innovation program under grant agreement No. 865131 for TCTool Project,
and has been partially funded by the projet “5R – Cervera Network in robotic technologies for intelligent
manufacturing”, contract number CER-20211007, under “Centros Tecnológicos de Excelencia
Cervera” (founded by “The Centre for the Development of Industrial Technology (CDTI)”). The authors
would like to thank TWI Ltd. for conducting the tensile tests and optical microscopy.
TCTool project partners: GKN-Fokker Aerospace, TWI Ltd., Andalusian Foundation for Aerospace
Development – Advanced Center for Aerospace Technologies, Brunel University London, London
South Bank University, Acroflight Ltd
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Design against distortion for aerospace-grade additively manufactured parts - PADICTON
Collections: Brunel Composite CentreAdditive manufacturing (AM) is a computer-controlled 3D printing process with increasing demand in the aerospace sector. This manufacturing process offers the production of lighter components, design flexibility, reduced labour effort and material cost, as well as decreased waste generation compared with subtractive manufacturing. Additionally, AM can provide parts availability at the point of use, significantly improving the supply chain. However, producing advanced high-temperature AM thermoplastic components remains a challenging task as these require a high-temperature build chamber environment that is prone to producing parts with thermal stresses and warpage. PADICTON project aims to develop a tool capable of accurately and rapidly predicting and correcting such distortions, offering improved quality of the produced parts and minimising rejection rates. Creating this tool requires conducting a comprehensive mechanical and thermal characterisation campaign to optimise the print parameters and part geometry. In this study, the concept of the project and the findings of the initial mechanical and optical characterisation tests for two AM processes, namely fused deposition modelling and selective laser sintering, are presented and discussed.The authors would like to acknowledge the PADICTON partners, namely FDM Digital Solutions, e Xstream Engineering, part of Hexagon Manufacturing Intelligence, AMendate, as well as the Topic
Manager of the project, Airbus, for their assistance and encouragement towards the realisation of the
activities. In addition, the consortium would like to express its gratitude to EOS for their technical
support. Furthermore, the activities of PADICTON project have received funding from the Clean Sky 2
Joint Undertaking under the European Union’s Horizon 2020 research and innovation programme under
grant agreement number 86481