Tab. 1: Materials TEPEX dynalite 104-RG600 (4) (Bond Laminates) Organic sheet Longitudinal Transverse Fibers roving glass Fabric twill 2/2 Area weight g/m² 600 Yarn tex Fig. 1: Process chain for the new concept 1200 1200 Weight rate % 50 50 PP Density g/cm³ 1.69 Fiber content % vol. 47 Thickness per layer mm 0.5 Tensile strength MPa 415 Ultimate stress MPa 365 Tape CELSTRAN CFR-TP PP-GF70 Ticona Fibers unidirectonial glass Fiber content % vol. 45 Matrix PP Width mm 12 Thickness mm Fig. 2: Reinforcement orientation and direction of the local load Polymer 0.25 properties, as well as its vibration behaviour, can be directly influenced and improved. Figure 3 shows the influence of reinforcing layers on the mechanical properties (Young’s Fig. 3: Mechanical improvements in reliance on number of reinforcements tensile modulus and tapes is much higher than the modulus of stress) of tensile specimens made from PPa multidirectional oriented base structure. GF organic sheet and PP-GF tapes applied This is particularly advantageous for large in the load direction. components or parts with lower mechanical properties in conjunction with high loads if In a first step, a process study was perforthe fibre alignment is not in the direction of med to evaluate the influence of the in-situ the local load (Figure 2). tape placement process parameters on the adhesion between base material and tapes. Additionally, the part’s overall mechanical A textile-reinforced base structure with behaviour in terms of bending and strength a polypropylene matrix system (organic sheets: Tepex Dynalite 104-RG600 PP supplied by Bond Laminates) and a long fibre-reinforced compression moulded part (also based on PP-GF) were chosen as base materials. Commercially available unidirectional endless reinforced thermoplastic tapes (PP-GF) served as semi-finished parts for the local reinforcement. Table 1 provides detailed information on the materials. It could be shown that the energy release rate (GIc), which provides information on the degree of adhesive strength, depends on the hot gas flow (hydrogen/oxygen mixture) as well as the tape depositing velocity. The dependence between gas flow and speed follows a linear mathematical law. However, the best experimental results can be achieved with the combination of 6 [Nl/ min] gas flow and 6 [m/min] velocity for No81 May - June 2013 / jec composites magazine 65