JEC COMPOSITES MAGAZINE - Issue #36 - October 2007 - 54

USERS’ PLATFORM Succesful partners g…/… Composite cooling ducts rigidity of this core enables it to be used as an inner lining during the manufacturing operation. The adjustment has been made by SERAM together with DJP. Rotational moulding tools have been designed and made by DJP according to SERAM advices. - An initial reinforcement shapes a fibreglass E-type form, used as a galvanised insulator. This reinforcement is placed as a preform on the liner serving as the core. It is relatively thick for economic reasons: - A second carbon fibre reinforcement of the HR type placed on the glass prereinforcement provides the desired mechanical resistant and makes the devices considerably lighter; - An epoxy resin matrix of the 80°C class. Thus, the definition of the two products presented design difficulties which were removed as soon as the decision was made to separate the various functions required. The manufacturing difficulties were particularly numerous, the main ones being: - Casting the flanges with the other various by rotational moulding parts as well as shrinkage of the different liner materials, according to the geometric specifications; - The dimensional stability of the composite parts; - The integration of the various mechanisms within the products; - The watertightness of the various compartments to be sectioned off; - The “in-one-shot” manufacture. These functions were ensured in these two products (sluice-gate and Y-shaped bypass) in a hollow body requiring neither assembly nor adhesive, and by means of RTM (Resin Transfer Moulding). Furthermore, these composites consist of thermoplastic materials combined with thermoset materials which together are able to meet the demands of the various functions to be covered. The valve body is a dual-conduit distributor that incorporates the same features as the Y-duct. To ensure that it functions correctly, it has internal devices that are incorporated into the liner, that enable a deflecting valve made of a composite to be inserted which, depending on its position, can diver the liquid into one or other of the directions chosen. This valve is operated from outside which means its must have special provision to ensure the movement while guaranteeing that it is watertight through the liner and the composite. In this arrangement, the liner ensures the water tightness and the composite the mechanical resistance. The difficulty has been to ensure that the valve was completely watertight when at rest on one or other of the surfaces. Mechanical resistance and distortions of the valve body were calculated through finite elements method using COSMOS software (figure 3). Fig. 4: the whole assembly Fig 3: finite element analysis of the sluice-gate The results of the calculations were used to define the Y-duct whose mechanical properties were similar. These two devices, which are polymorphous hollow bodies, are entirely made of composite materials, flanges included, in « one shot » without any assembling or gluing. They make up a block to take seawater (figure 4). The two products present an interface that is strictly identical to the materials used in conjunction with each other, such as the threaded joint on the surface of the liner flange and stainless steel fixing inserts countersunk into the composite and crossing the liner. The Mecatronic cluster made the assembled parts as inserts in ducts and sluice-gates of the « Vaneo » program. The design of the sluice-gate mould has been carried out by the Mecatronic cluster while DJP kept the design of the Y-duct one. Finite analysis computations have been made by the cluster under the DJP specifications. Specification requirements led to a separation of functions architecture. The « watertightness » function is ensured by an inner thermoplastic liner, separately made, with the help of SERAM, monolithically without any weld. The “mechanical” function is ensured by a composite materials casing surrounding the liner in which stainless steel inserts are embedded to allow the fastening of the two products on the engine cooling circuit. One of the development difficulties has been to combine thermoplastics with thermoset materials. Each of the two products is designed and produced using the following components: A plastic (special polyethylene) liner, manufactured by rotational moulding, that is completely waterproof to the outside and through its design avoiding any contact between the fibres of which the structure is composed, and the liquid carried in the devices. Consequently, stress is not put on the galvanised couplings linking the various components that are needed for the operation of the devices. The JEC Composites Magazine / No36 October - November 2007

JEC COMPOSITES MAGAZINE - Issue #36 - October 2007

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