Papers by Keyword: Light Weight Engineering

Abstract: The long term behaviour of fibre reinforced polymers is important for many uses. In this publication experiments are described in which three different carbon fibre epoxy compound specimens, with different fibre orientations, are compared. For a comparison to metallic materials, as well as to get a benchmark, steel and aluminium specimens are also tested. All specimens are loaded with constant loads; the investigated load types are bending and torsion. In the experiments two different scenarios are investigated. The first scenario compares the creep behaviour under uniform start deflections and the second scenario compares the creep behaviour under uniform load conditions.

Abstract: Light weight engineering and composite technologies are key strategies in modern product development in mechanical engineering as well as in biomedical applications, where innovation is driven by novel material concepts and surface functionalities. Designed or customized surface properties by advanced coating technologies are an important discipline in this context. Ceramic, metallurgical and cermet layers can be manufactured in a most appropriate way by high energetic thermokinetic deposition techniques like plasma spraying, electric arc and last not least by supersonic flame spraying (HVOF). These technologies perform high deposition rates, high flexibility to use various materials and their combinations and applications in micro to macro scale products. The final properties of the coatings and layer composites do not just depend on the properties of the combined materials but, as in the case of ceramic coated light metals, are distinctly affected by the occurring residual stresses and their interaction with operational load stresses. With respect to the complex geometries of most components, their dimensional and positional tolerances a further strong influence of the robot kinematics of the plasma or HVOF torches during coating manufacturing is observed. By combining the expertise in materials and manufacturing engineering coatings and composites with high performance and reliability can be achieved. This is shown in the development of functionally coated cylinder liners and crankcases for ultra light weight engines as well as for ceramic coated bioinert and biodegradable substrates in medical surgery. It will be shown that cast engine block bores can be directly coated by using an automated HVOF process, obtaining improved coating results. The internal coating process by hypersonic flame spraying is a superior technological alternative to the APS process for high quality cylinder liner and engine crankcase applications. The applications of such ceramic and cermet coatings are not limited to automotive and biomedical applications, i. e. for wear and friction properties or biomedical compatibility, but can be used for tailored thermophysical, electrophysical or catalytic properties in various technical systems.

Abstract: Actual requirements in the automotive industry are the reduction of fuel consumption and pollution emission, engine efficiency improvement, as well as cost reduction. Most of these requirements are fulfilled by reducing the total weight of the vehicle. This results in an increasing utilization of light metal components for engine applications. Significant weight savings are obtained by changing the engine block material from cast iron to aluminum or even to magnesium aluminum hybrid constructions. Despite of all advantages the industrial implementation of light metals is often inhibited by their poor surface properties especially concerning wear and tribological behavior. Due to the highly loaded operation conditions a cylinder liner surface reinforcement is necessary. A very promising technological alternative is the internal cylinder reinforcement by using HVOF (high velocity oxygen fuel) sprayed coatings. By using these advanced high energetic coating technologies, material combinations containing solid lubricant ceramic dispersions can be deposited. The thermal spray processes represent a cost effective and flexible solution for ultra light weight engine technology. This research is focused on the development of HVOF sprayed coating systems for cylinder liners, the coating optimization and the cost effective implementation of this hypersonic spray technology in a series production process. It will be shown that cast engine block bores can be directly coated by using an automated HVOF process, obtaining improved coating results. The internal coating process by hypersonic flame spraying is a superior technological alternative to the APS process for high quality cylinder liner and engine crankcase applications.

Abstract: Light weight engineering by materials and by design are central challenges in modern product development for automotive applications. High strength structural ceramics and components were in the focus of R & D in automobile development since the 1970's and CMC have dominated advanced materials engineering in aerospace applications. The limiting factor for their market acceptance was the high processing and manufacturing cost. The automotive industry requires technical performance and high economic competitiveness with tough cost targets. The potential of ceramic matrix composites can be enhanced, if new fast and cost effective manufacturing technologies are applied. This is demonstrated in the case of SiC composites for high-performance disk brake rotors for passenger cars. Light metal composites are promising candidates to realize safety relevant lightweight components because of their high specific strength and strain to failure values, if their stiffness and their thermal and fatigue stability is appropriate for the application, i.e. in power train and wheel suspension of cars. Tailor-made fiber reinforcements in light metal matrices can solve this problem, but the integration of fibers with conventional manufacturing techniques like squeeze casting or diffusion bonding leads to restrictions in the component's geometry and results in elevated process cost mainly caused by long cyc1e times and the need of special tools and additional fiber coatings. A new manufacturing method for metal matrix composites (MMC) made by fast thixoforging is introduced. Thereby, prepregs consisting of laminated fiber woven fabrics and metal sheets or, alternatively, thermally sprayed metal coatings on ceramic fiber fabrics are used as preforms for an advanced thixoforging process for the manufacturing of Al-Si MMC components in mechanical engineering.