Epoxy resin system deployed in commercial vehicle suspension
Leaf springs are widely used in the suspension systems of commercial vehicles and SUVs and they must sustain various load conditions, such as longitudinal and lateral loads, and brake torque. Conventionally fabricated from steel, Kolon Industries (South Korea) has teamed up with fellow Korean companies Hyundai Motor Group and SK Chemicals to develop a leaf spring based on an epoxy resin composite that achieves an almost 50% weight reduction and features five-fold greater durability.
The new epoxy resin system combines fast curing with high toughness and was designed especially for thick composite sections (>100 mm). The system was developed to perform under elevated temperature and wet environments. It also offers improved NVH (noise, vibration, and harshness) behavior and fatigue durability. To optimize the cure cycle and minimize distortion in the thick composite (>100mm), both cure kinetics and chemo-rheological model parameters were implemented in the simulation software used. This made it possible to predict and find adequate curing conditions.
The leaf spring was also developed to be damage-tolerant so that it retained the required structural strength or stiffness after accidental or discrete damage. Finite element-based multi-scale and progressive failure analysis was used to predict the residual fatigue life and to assess the effect of a damage event on the performance of the composite leaf spring.