Carbon/biocomposite hybrid vehicle structures for reduced weight, cost and environmental impact (CARBIO)

与传统的钢和铝合金相比，碳纤维/亚麻混杂复合材料在振动声、重量和成本方面具有优势，这与最大限度地减少排放和燃料消耗有关。但是，环氧碳纤维/亚麻混杂复合材料的振声特性及其与复合材料结构强度的关系仍未被探索，这是材料技术应用于制造更好的部件的绊脚石。随着亚麻纤维和碳纤维复合材料在汽车零部件中的广泛应用，需要正确理解振动-声学问题及其在结构设计和制造中的作用。因此，卡比奥项目涉及调查选定部件/系统的振声水平，以确定可调频率，确定和量化温度变化、面板结构和车身组件之间的振声耦合，以及噪声水平相对于完全以环氧/碳纤维、钢和铝为基准的部件的益处。这项研究源于这样一个事实，即随着越来越严格的环境法规和要求，噪声和振动已成为汽车制造的非常重要的设计考虑因素。现代汽车消费者意识到他们的环境需求，因此要求最经济的汽车，最舒适的驾驶，显然也是最便宜的。因此，汽车行业已经成为一个消费者驱动型行业，噪音、振动和对环境的苛刻程度已成为衡量设计卓越和车辆性能的指标，这一因素在汽车销售中得到了强烈反映。降低噪音和振动的一个合理途径是提高汽车零部件制造材料的减振性能。目前，在传统汽车中，车身覆盖件主要由斯蒂兰铝合金制造，在高性能汽车中，车身覆盖件主要由环氧碳/玻璃纤维复合材料制造。如果汽车工业要获得可接受的驾驶环境和舒适性，就需要采取更有效的降噪和减振措施，因为汽车结构质量是对环境要求的响应。该项目承认，与天然纤维混杂的复合材料是解决振动声问题的关键解决方案。燃烧纤维(亚麻)具有更高的减振性能。除了减轻质量外，复合材料在降低噪音和振动、抗冲击、能量吸收能力等方面提供了一致的潜在优势。它们还在制造过程中提供了优势，例如生产小批量零件的成本降低，以及集成的可能性，即可以用更少的子部件制造的结构。复合材料还具有独特的适应性：通过适当选择组成材料和增强纤维的取向，为满足与传统材料不匹配的设计要求而量身定做。这对于性能优化至关重要，目标是最大限度地减少质量和/或应力集中，保证所需的性能。热塑性塑料和其他轻质材料的使用也使英国原始设备制造商与欧盟的报废汽车指令保持一致，因为到2015年，汽车必须由95%的可回收材料制造，85%通过重复使用或机械回收，10%通过能源回收或热回收。预计拟议中的项目将使英国汽车业在全球行业中占据领先优势。

Carbon/flax fibre-reinforced hybrid composites offer advantages in terms of vibroacoustic, weight and cost when comparedto conventional steel and aluminium alloys which can be related to minimisation of emissions and fuel consumption.However, vibro-acoustic characteristics of epoxy-carbon fibres/flax hybrid composites and their co-relation to structuralstrength of the composite remain unexplored and a stumbling block in the application of the material technology tomanufacture better components. The increased application of both flax fibres and carbon fibre composites in automotivecomponents requires proper understand of vibro-acoustic problems and their effects in structural design andmanufacturing. The CARBIO project, therefore, involve investigating the vibro-acoustic levels for selected components/systems for determination of tuneable frequencies, determination and quantification of vibroacoustic coupling betweentemperatures variations, panels architecture and body assembly contributions and noise levels benefit againstbenchmarked fully epoxy/carbon fibre, steel and aluminium components.The study stems from the fact that with increasingly stringent environmental regulations and requirements, noise andvibration have become very important design considerations for automotive manufacturing. Modern vehicle customers areaware of their environmental needs and therefore demand the most economical car, the most comfortable to drive andobviously the cheapest. As a consequence, the automotive industry has become a consumer driven industry where noise,vibration and environmental harshness has become a measure of design excellence and vehicle performance, a factreflected strongly in vehicle sales. A rational approach to reducing noise and vibration is to improve the damping propertiesof the materials from which the car parts are manufactured. Currently, body panels are mainly manufactured from steeland aluminium alloy in conventional vehicles and epoxy - carbon/glass fibre- reinforced composites in high performancecars. More effective measures for noise and vibration reduction are desirable if the automotive industry is to achieve anacceptable driving environment and comfort as vehicle structural masses are reduced in response to environmentaldemands.The project acknowledge that hybrid composites with natural fibres are a key solutions to the vibroacoustic problem sincenatural fibres (flax) have much higher damping properties. In addition to the reduction of mass, composite materials offerconsistent potential advantages in terms of noise and vibrations reduction, impact resistance, energy absorption capability. They also offer advantages in the manufacturing process, such as cost reduction for producing low volume pieces and thepossibility of integration, i.e. structures which can be made with fewer sub-components. Composites also possess a uniquecapability: to be tailored in order to meet design requirements which are ill-matched for conventional materials, by properlychoosing the constituent materials and the orientation of the reinforcement fibres. This is of primary importance for theperformance optimization, the target objective being a minimization of the mass and/or of stress concentrations,guaranteeing the required performance. Use of thermoplastics and other lightweight materials also aligns UK OEMs withthe end of life vehicle EU directive in that by 2015 , vehicles must be constructed of 95% recyclable materials, with 85%recoverable through reuse or mechanical recycling and 10% through energy recovery or thermal recycling. It is envisagedthat the proposed project will give the UK automotive industry a leading edge in global industry.