Sensor Integrated Leaf SpringCopyright: SLA
By changing the material from steel to glass fiber reinforced plastic, fiber optic sensors can be integrated into the leaf spring, enabling efficient condition and health monitoring.
Significant weight reduction is achieved by the use of glass fiber reinforced plastic (GFRP) for leaf springs. In addition, the material damping properties of GFRP can also be used to improve Noise, Vibration & Harshness behavior of vehicles. However, the fatigue behavior of GFRP is very complex, especially when cyclic, dynamic and thermal loads are taken into account. The increased number of inspections is very unattractive from the perspective of the customer, since this leads to an increased expenditure of time and cost. Therefore, when using a GFRP leaf spring, a very conservative design has to be carried out in which the structural integrity of the GFRP leaf spring is underestimated.
The use of Structural Health Monitoring (SHM) in combination with GFRP leaf springs offers great potential. Fiber optic sensors are of particular interest. They can be integrated directly during production and thus enable strain measurements within the leaf spring.
This project investigates a monitoring approach based on structural analysis. A close to reality setup consisting of leaf spring, shackle and bolt connection is considered. In the first step, the structure is characterized. Effects such as edge disturbances of the bearings and the load application are considered. In the next step, the expected damages are integrated into the model in order to investigate their effects on the structural behavior and to derive sensitive structural damage indicators.