- 2016 Elsevier Ltd. All rights reserved. Failure in composite materials consists of a series of events that initiate at a scale that is in the range of a few fiber diameters and is commonly described as a microscale. A larger scale, called a mesoscale, governs further occurrence of the failure events. This scale is given by a representative volume element, which represents geometrical features such as layer thickness and fiber orientation and distances over which stress field perturbations by the failure events interact. Chapter 14 in this book described a multiscale approach to the deformational response of composites at the structural (macro) scale. This chapter will address depletion of load-bearing capacity (strength) at the macroscale, also by a multiscale approach. The role of virtual testing in the multiscale approach will also be discussed.