Research on methods to reduce the scattering and to increase the fatigue life of unidirectional fibre-polymer-composites

复合材料研究的一个主要焦点集中在这类材料的破坏行为上。特别是长期承受疲劳载荷的结构，例如卡车的板簧，具有很大的意义。玻璃纤维在最近几年成功地成为最合适的钢板弹簧材料。在这种情况下，玻璃纤维的最大优点是它们的低杨氏模量，由此可以最容易地满足高弯曲变形的要求。自2006年以来，戴姆勒Sprinter的钢板弹簧大批量生产。它必须是目标，介绍GRP钢板弹簧，特别是重型卡车。通过替换钢弹簧，可以实现约75%的弹簧质量重量减轻，这意味着卡车后轴的重量减轻130 kg。这种质量节省可用于增加有效载荷并降低CO2排放。未来玻璃钢钢板弹簧的市场占有率将进一步提高，这意味着与钢材的竞争将更加激烈。要想保持与玻璃钢钢板弹簧的竞争力，就必须充分挖掘玻璃钢钢板弹簧的潜力。为了达到这一目标，必须解决许多基本问题，包括：非经济安全系数，目前用于这些部件的设计;疲劳寿命的计算;所有增加寿命的机会。通过降低板簧层压板的强度分散和测试增加疲劳寿命的新概念，可以达到所述目标。

A main focus of composite research concentrates on the failure behaviour of this material group. Especially structures which are fatigue loaded for long term are of great interest, e.g. leaf springs for trucks. Glass fibres succeeded in the recent years as the most suitable material for leaf springs. The big advantage of glass fibres for this case is their low Young's modulus, by which the requirement of high bending deformation can be fulfilled the most easiest. Leaf springs for the Daimler Sprinter are manufactured in large series since 2006. It must be the aim, to introduce the GRP-leaf springs especially for heavy trucks. By substituting steel springs a weight saving of about 75% of the spring mass is achievable, that means a weight reduction of 130 kg at the rear axle of the truck. This mass saving can be used for increasing the pay load and to lower the CO2 emission. In future an increase of the market share of the GRP leaf spring can be expected, that means a stronger competition to steel.To keep competetive with the GRP leaf spring it is absolutely necessary to scoop out all the potential of the material. To reach this goal a lot of fundamentals have to be worked out; this concerns- the non economic safety factors, which are used at this time for the design of these components- the calculation of the fatigue life- all chances to increase the life time.The sketched aim can be reached by lowering the scattering of strength of the leaf spring laminates and by testing new concepts to increase fatigue life.