Strengthens Adhesion of Prepreg to Aluminum Components France Saint Jean Industries Increases Rigidity of Aluminum Suspension Knuckle by 26%
In automobiles or trucks, the connecting parts used for steering and suspension systems directly affect the ride comfort, durability, and drivability of the vehicle. Therefore, the performance of these components is directly related to the driver's perception of vehicle quality. One of these components is the suspension knuckle, which fixes the upper and lower suspension components to the wheel support assembly and is the mounting point for the wheel spindle and hub. Therefore, rigidity and durability are the two main components that evaluate the component. Performance.
Saint Jean Industries of France cooperated with its nearby Hexcel Les Avenières (Hesse's European Carbon Fiber Reinforced Materials Center of Excellence) to develop a 'carbon fiber/aluminum' suspension knuckle with a hybrid material compared to that of aluminum. Day, its rigidity has increased by 26%. As a global supplier of components for automotive, aerospace, motorcycle, heavy truck and industrial applications, Saint Jean Industries is a lightweight solution using titanium, aluminum and high strength steel. leader.
For example, the company's patented COBAPRESS technology achieves higher performance and lighter quality in aluminum parts through the integrated application of casting and forging technologies. For this knuckle, the company needs aluminum. The weight and the general rigidity of cast iron, and this is exactly the difference that carbon fiber can bring. The components of this 'aluminum/CFRP' hybrid material do not increase the volume of the component, but only add a few millimeters to the component. The thickness, which can accommodate the tight installation space constraints, also allows a single component design to be used in a variety of vehicle models. This design was developed in conjunction with Hexcel. Reinforcement consists of multiple layers of unidirectional HexPly M77 fast-curing epoxy prepregs for automotive structures, each layer being laid in a different direction.
Lionel Duperray, Technical Director of Saint Jean Industries, explained: 'The load on the steering knuckle is very complex, including impact loads and fatigue loads for durability. To this end, we have established a finite element analysis model (FEM), but we did not The expertise in composite materials, so we shared our model with Hirsch. They used their own FEM experience to develop composite laminates based on our design and load requirements.
This prepreg reinforcement also increases the maximum strength of the knuckle before failure, and it was bonded to the aluminum knuckle with Hexcel's new Redux 677 fast-cure epoxy film. The film was developed specifically for mass compression molding of metal/carbon fiber composite structures to prevent direct contact between carbon and aluminum, eliminating the risk of galvanic corrosion.
In high-volume production of automobiles, Hexcel has technology to develop and produce prepreg reinforcements. Typical yield is one reinforcement per minute. Saint Jean Industries first uses its COBAPRESS process to manufacture all the components including knuckles. Aluminum parts, the company produces more than 15 million parts per year. Then, the parts are cleaned to prepare the surface for bonding. Next, the prepreg is reinforced and placed on the part and then at a temperature of about 150°C. Curing in a press, this has no effect on the microstructure of aluminum.
The company was able to apply and cure this reinforcement in less than 2 minutes, and thus easily adapted to the automated processing cycle of its production knuckle. This reinforced knuckle is still in the pre-production stage of development. Duperray said that they need a bonding tool to hold the reinforcement. The cost of the bonding tool is similar to the company's cost for the casting and forging tool project.