The increasing incorporation of lightweight, high-performance composites into modern structural designs represents a natural step in the optimization roadmap defined to satisfy the demanding needs and regulations of the transport industry nowadays. The outstanding specific mechanical properties of composites make possible stronger, faster, lighter, safer and greener vehicles. But the full, efficient exploitation of the advantages of composites still tackles challenging tasks, such as the monitoring of structural integrity or the reduction of development costs. In particular, a pursued aim of the engineering community is the eventual replacement of expensive and time-consuming test campaigns by accurate computational predictions of the mechanical behaviour and failure of composite materials. In this context, virtual testing constitutes a framework of advanced analysis and simulation techniques capable of bridging different length scales by transferring, from one level to the others, relevant information of the properties and failure mechanisms of and between the constituent materials.