JEC COMPOSITES MAGAZINE - Issue #52 - October 2009 - 42

FEATURE Torsional performance and damage tolerance of braiding configurations High-performance materials like carbon-fibre-reinforced plastics (CFRP) are used in high-tech applications for their high specific strength and stiffness. Besides material costs, production techniques have a considerable influence on the overall product costs of CFRP structures. Customized technologies together with automated processes are the conditions for modern, competitive composite manufacturing. Preforming based on textile techniques fulfils these requirements. Here, the dry reinforcement fibres are manufactured in a near net-shape configuration. The preform is then impregnated using a process such as Resin Transfer Moulding (RTM) or Vacuum Assisted Resin Infusion (VARI) [1]. ANDREAS ERBER, SCIENTIFIC ASSISTANT, INSTITUTE OF AIRCRAFT DESIGN (IFB), UNIVERSITY OF STUTTGART & PROF. KLAUS DRECHSLER, DIRECTOR, CHAIR FOR CARBON COMPOSITES (LCC), TU MUNICH is a design and manufacturing challenge, as seen in Figure 1(b). here are different applications for drive-train systems in the automotive, aerospace, marine and industrial sectors. In automotive drive-train and aerospace transmission systems, it is possible to save a bearing by using long, axially stiff shafts [2]. Axially oriented fibres are required for such an application. Then weight can be saved on the torsional shaft itself, and therefore on the complete system [3]. T Drive shafts In both automotive and aerospace applications, impact damage can occur during the part’s life cycle. In a composite design process for aerospace, impact scenarios due to a tool drop, tyre burst or bird strike have to be taken into account [4]. The braiding preforming technique offers the possibility to produce high-performance drive shafts fast and cost-effectively. Using different fibre architectures, a customized preform can be produced for each application. Fig. 1: (a) Impact configuration and (b) interdependence of mechanical properties. Interacting requirements As described above, there are several requirements on drive shafts. They need to be stiff in the axial direction, to carry high torsional loads and to be damage tolerant, all at the same time. Because these requirements are partially opposed, fulfilling them Figure 1(a) shows the set-up principle for impact testing of transmission shafts. To achieve high torsional performance, the reinforcement fibres have to be oriented in the 45° direction in the shaft. However, axially oriented fibres are necessary to achieve high axial stiffness. The axial stiffness of the fibres blocks the shaft, preventing it from shifting during the impact. Hence, the full impact energy is more or less received by the laminate, reducing the residual strength of the transmission shaft. jec composites magazine / No52 October 2009

http://www.jeccomposites.com

JEC COMPOSITES MAGAZINE - Issue #52 - October 2009

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #52 - October 2009