Design and Analysis of Composite Structures for Automotive Applications

Foreword

From a materials science point of view, composite materials of glass and carbon fibers have a specific potential and already some practical importance in several applications under high dynamic loads. Comparing the fibers, glass fibers are the better material for spring applications because their lower modulus of elasticity compared to carbon fibers. This is favorable in terms of high strokes and deformation requirements. Due to their high specific strength and the stiffness of composite materials, it is in principle possible to achieve weight savings of 30 – 70% of the weight of a steel spring depending on application. In addition to reduce the unsprung masses for suspension, it is also possible to improve driving dynamics as well as noise, vibration and hardness behavior (NVH), since the material properties are better in some significant areas. Furthermore, due to the high corrosion resistance and resistance against other environmental influences, surface protection is not necessary in most of the applications.

However, the usage of composite materials for springs have not reached high quantities due to some limitations. Load transmission requires special designs. Considering suspension coil springs, high loads transverse to the main load direction occur. Therefore, the load transmission does not follow ideally to the fiber direction and only medium loads can act on the matrix. In addition, in the case of large‐scale production and the available manufacturing processes, ...