Abstract

Product developers often face the challenge to increase the efficiency of mechanical systems, e.g. in the automotive industry a reduction of weight results in a higher energy efficiency and less emissions. Therefore, the development of lightweight design solutions gains importance. Beads are commonly used design elements to decrease the thickness and therefore the weight of sheet metal components while maintaining the stiffness. An approach to enhance the stiffening effect of beads is the lamination of unidirectional fiber-reinforced polymers (UD-FRP) in the top flange area of the bead. However, the additional lamination of UD-FRP is expensive and adds mass to the component, which has an adverse effect on the intended weight reduction. Therefore, an optimization method is developed to determine an initial design of sheet metal components with fiber-reinforced beads. To ensure a time-efficient optimization, a substitution model of the fiber-reinforced bead structure is necessary. In this contribution, a method to derivate a substitution model of a fiber-reinforced bead is presented. As a basis, a detailed finite element model of a fiber-reinforced bead is introduced. This model is used to numerically analyze the contact and failure behavior of the combination of sheet metal and UD-FRP. The validation of the detailed model is carried out by comparing numerical results of a three-point bending test with the according experimental data. To create a substitution model of the reinforced top flange area of the detailed model, shell elements are used to replicate the behavior of the combination of sheet metal and UD-FRP. In order to achieve an equivalent behavior, the material parameter sets of these shell elements are modified. Due to the huge number of material parameters, a manual modification is too time-consuming and inefficient. Therefore, an evolutionary algorithm is implemented to generate optimized parameter sets in dependence of the utilized number of UD-FRP plies. In a further step, these sets are transferred to the optimization method to design fiber-reinforced sheet metal components. The results of the method are evaluated and presented based on the finite element models. A good accordance between the simulation results of the stress and deformation behavior of the substitution model and the detailed model can be shown. This method enables product developers to design fiber-reinforced sheet metal components.