Co-authors​ :

 Burak Ogun YAVUZ (UNITED KINGDOM), Ian HAMERTON (UNITED KINGDOM), Marco L. LONGANA , Jonathan P.-H. BELNOUE (UNITED KINGDOM) 

Recently, aligned discontinuous fibre-reinforced composites (ADFRCs) have been industrialised, demonstrating mechanical properties that can rival those of composites manufactured from continuous fibres. Consequently, university research groups, particularly involving HiPerDiF (High Performance Discontinuous Fibre) and TUFF (Tailored Universal Feedstock for Forming) have demonstrated that forming is easier when fibres slide over each other, either before curing (for thermoset resins) or at process temperatures (for thermoplastics). Unlike continuous fibre composites, at process temperatures ADFRCs can reach tensile strains of up to 50% before specimen breakage occurs [1, 2]. However, as the fibre sliding commences, the material undergoes large thinning and necking until complete separation occurs. This leads to expectations of a drop in material properties in the finished part. It is, therefore, crucial to identify these high-strain regions through simulations to ensure they align with the designed parameters. In this study, tapes comprising poly(L-lactic acid) (PLA) and carbon fibre tapes, manufactured with the HiPerDiF machine, are amalgamated into a 150 mm x 150 mm sheet layer. A material model for the prediction of the visco-elastic mechanical behaviour of the material under processing conditions [4] was developed and implemented in Fortran as a subroutine in the explicit finite element package Abaqus. The decoupling of in-plane tension properties and out-of-plane bending typical of a fibrous material was obtained using a combined shell and membrane elements approach [3]. Using this model, stamp forming of the sheets is simulated at selected isothermal process temperatures. Experimental results obtained isothermally are then compared with the simulation result.