Car transportation is responsible for 12% of the total CO2-emissions in Europe. With the legislation that is already in place for 2030, the emissions must decrease to about half of the levels of 2015. A promising way to contribute to reaching this goal is to reduce the weight of cars. The introduction of composite materials, in particular carbon fibre reinforced materials, is a promising way to decrease the weight, due to their superior properties. Cars made from Carbon Fibre Reinforced Polymer (CFRP) materials are considered to be 50% lighter compared to steel alternatives and 30% lighter compared to aluminium alternatives with similar performance.
However, predicting failure in composite materials is not as easy as in isotropic materials like metals. Failure depends on the loading conditions, material orientation, and how they are stacked. To accurately predict initiation of failure, models with a resolution that is about 10 to 100 times finer than used for metals are needed. They are however too computationally demanding and to use them within current design loops is not feasible, thus more efficient tools are needed.
One part of this thesis covers how an efficient analysis framework can be set up, which allows the automotive industry to use tools and models that are familiar. The framework screens complete car models and presents potential critical hot-spots. These are then remodelled in higher detail for verification.
Composite reinforcements exist in a number of different forms, uni-directional tapes, woven textiles or oriented mats that are stitched together. These are then made with a variety of production methods. Due to their use within the aerospace industry, the most explored material for simulation is uni-directional tape-based pre-impregnated composite materials. Since the automotive industry needs cheaper materials and higher production rates, other material systems are of interest. One such system is Non-Crimp Fabric reinforcement composites.
In this work, understanding of how failure initiates in Non-Crimp Fabric reinforcements, given their orthotropic properties, is also studied. A set of criteria is proposed to predict all failure modes in these materials. The criteria are validated with physical experiments and implemented into commercial software.