FINITE ELEMENT INVESTIGATION OF “CRADLE TESTS” FOR THE MECHANICAL CHARACTERIZATION OF PULTRUDED RODS UNDER COMPRESSION
Topic(s) : Special Sessions
Co-authors :
Nicolas DARRAS (UNITED KINGDOM), Iheoma C. NWUZOR (UNITED KINGDOM), Bohao ZHANG (UNITED KINGDOM), Laura Rhian PICKARD (UNITED KINGDOM), Michael R. WISNOM (FRANCE), Richard S. TRASKAbstract :
1 Introduction
NextCOMP (Next Generation Fibre-Reinforced Composites) is a research programme aiming to improve the compressive performance of light-weight composite architectures [1]. To do so, the development of bioinspired hybridized and hierarchical structures is being investigated. Several structural configurations are being investigated to produce hierarchical composites employing highly aligned unidirectional pultruded rods [2]. Through the assembly and processing of these rods, by Resin Transfer Moulding, structural members (struts) can be designed and produced with enhanced compressive performance , see Figure 1. Additional structural rigidity between the individual elements can be obtained by overbraiding the rods [3]. This approach gives a wider design space for the composite structure. The purpose of this study is to control the internal organisation of hierarchical composites and gain a better understanding of their impact on the composite’s mechanical compressive performances.
2 Manufacture and test of specimens
The specimens are manufactured from carbon fibre pultruded rods by using a process of resin transfer moulding, as shown in Figure 1. Those rods can be used without upgrades, or they can be overbraided with different materials: carbon fibre, basalt, aramid or Zylon™ fibre [3]. Using the combination of the different techniques and materials results in a final hierarchical hybrid composite. The process of manufacturing the specimen has been investigated previously with the use of a CT scanner, see Figure 1, to keep track of the defects induced by the flexible tool and the resin transfer moulding processes[4]. The manufacturing process has been optimised through the development of a steel mould , which offers an opportunity to control the internal stacking of the rods within the strut structure. A bending test has been modified to investigate the compression performances of the manufactured struts .
3 Concluding remarks
The quality of the manufactured specimens, i.e. the struts manufactured utilising the flexible polymer membrane and rigid steel mould, is determined by 2D microscopy and 3D micro-CT scans. The influence of the internal architecture on the compressive structural performance of the different composite configurations has been assessed through a dedicated bending test and through a finite element simulation (Figure 2) to confirm the experimental findings. The key results of this study will be presented.
4 Acknowledgements
The authors kindly acknowledge the funding for this research provided by UK Engineering and Physical Sciences Research Council (EPSRC) programme Grant EP/T011653/1, Next Generation Fibre-Reinforced Composites: a Full Scale Redesign for Compression in collaboration with Imperial College London.
NextCOMP (Next Generation Fibre-Reinforced Composites) is a research programme aiming to improve the compressive performance of light-weight composite architectures [1]. To do so, the development of bioinspired hybridized and hierarchical structures is being investigated. Several structural configurations are being investigated to produce hierarchical composites employing highly aligned unidirectional pultruded rods [2]. Through the assembly and processing of these rods, by Resin Transfer Moulding, structural members (struts) can be designed and produced with enhanced compressive performance , see Figure 1. Additional structural rigidity between the individual elements can be obtained by overbraiding the rods [3]. This approach gives a wider design space for the composite structure. The purpose of this study is to control the internal organisation of hierarchical composites and gain a better understanding of their impact on the composite’s mechanical compressive performances.
2 Manufacture and test of specimens
The specimens are manufactured from carbon fibre pultruded rods by using a process of resin transfer moulding, as shown in Figure 1. Those rods can be used without upgrades, or they can be overbraided with different materials: carbon fibre, basalt, aramid or Zylon™ fibre [3]. Using the combination of the different techniques and materials results in a final hierarchical hybrid composite. The process of manufacturing the specimen has been investigated previously with the use of a CT scanner, see Figure 1, to keep track of the defects induced by the flexible tool and the resin transfer moulding processes[4]. The manufacturing process has been optimised through the development of a steel mould , which offers an opportunity to control the internal stacking of the rods within the strut structure. A bending test has been modified to investigate the compression performances of the manufactured struts .
3 Concluding remarks
The quality of the manufactured specimens, i.e. the struts manufactured utilising the flexible polymer membrane and rigid steel mould, is determined by 2D microscopy and 3D micro-CT scans. The influence of the internal architecture on the compressive structural performance of the different composite configurations has been assessed through a dedicated bending test and through a finite element simulation (Figure 2) to confirm the experimental findings. The key results of this study will be presented.
4 Acknowledgements
The authors kindly acknowledge the funding for this research provided by UK Engineering and Physical Sciences Research Council (EPSRC) programme Grant EP/T011653/1, Next Generation Fibre-Reinforced Composites: a Full Scale Redesign for Compression in collaboration with Imperial College London.