报告人：英国诺丁汉大学 陈帅 博士
题 目：Simulation and Optimisation of Automated Preforming Process for Complex Composite Components
The development and optimisation of automated fabric preforming processes is critical for the adoption of composite materials for low cost, high volume applications. This research focuses on simulating the forming of fabric plies into complex 3D shapes to evaluate the feasibility of using matched-tool forming (MTF) and double diaphragm forming (DDF), in order to manufacture low cost fabric preforms suitable for liquid moulding processes. The fabric forming behaviour has been investigated to understand the deformation mechanisms and the cause of defects, in order to seek feasible solutions for defect reduction. A material model has been developed to successfully identify the cause of forming-induced defects, and has been used to optimise preform geometry and process parameters to mitigate defects. An optimisation methodology has been developed for placing local inter-ply stitches on multi-ply preforms, where the stitches enable multiple plies to be joined together to aid robotic handling. A two-step optimisation method was developed to optimise the boundary conditions for a MTF scenario using spring-loaded clamps and/or a segmented blank holder. The optimisation algorithm was used to determine the location and size of the clamps around the blank perimeter and the stiffness of the attached springs. In DDF, darts were added to preforms for DDF to alleviate fabric bridging and improve surface conformity, using the tensile stress in the yarns to identify suitable positions and orientations, minimising the effect on the mechanical performance of the component. Also, rigid blocks (so-called risers) were introduced to adjust the constraining forces around the fabric in DDF. Riser optimisation was implemented to determine a suitable scenario to place risers for defect-free preforms.
Dr Shuai Chen is a Research Fellow in Composites Research Group, University of Nottingham. His current research focuses on design, analysis, and optimisation of composites forming process for Automotive & Aerospace sectors. He has specialised in the development of composites manufacturing processes and simulations, and is committed to supplying feasible solutions for high-quality and defect-free preforms by material/process optimisation based on finite element (FE) simulation. To date, he has completed 24 papers, and served as a Session Chair of “Process modelling” for 21st International Conference on Composite Materials in 2017. Dr Chen is a member of Society for the Advancement of Material and Process Engineering (SAMPE), and a member of the Institute of Materials, Minerals and Mining (IOM3). During the last five years, he has worked for 3 EPSRC projects and 4 Innovate UK projects. Recently, he has been awarded two external grants to develop step-changing techniques for composites manufacturing.