Predictive Finite Element Method for axial crush of composite tubes
This thesis describes the development of a predictive Finite Element methodology for the crush behaviour and specific energy absorption of composite material tubes. Numerical studies were undertaken based on experimental data for the following composite materials: Continuous filament random mat (CoFRM) Glass/Polyester 6-ply laminate Braided Carbon/Vinylester o 2-ply, 3-ply, and 4-ply tubes o 0/+30°/-30°, 0/+45°/-45°, and 0/+60°/-60° fibre architectures The modelling approach consists of treating intralaminar and interlaminar behaviour of the composite separately. An existing finite element material model is used to model intralaminar behaviour and a validation is undertaken against coupon tests. Interlaminar behaviour is modelled via a new delamination contact interface based on fracture toughness concepts. The development and application of the delamination algorithm in the commercial FE code PAMCRASH is described and a validation against standard fracture toughness tests is included. This work contains a detailed description of the procedure used to obtain the input parameters for the PAM-CRASH material model, which were collected from a range of standard coupon tests. A description of the modelling technique for the tubes is included, which comprises geometry, meshing details, boundary and loading conditions, and output readings. Results show good agreement with quasi-static experimental data for all the different tubes investigated. The approach can be considered predictable as only coupon test data is used for the input parameters of the material model and the delamination contact interface.