Why is validation important? Validation of computational mechanics models is defined as ‘determining the degree to which a model is an accurate representation of the real world from the perspective of the intended uses of the model’, according to ASME V&V 10-2006. So, the validation of models of structural integrity for engineering design provides information about the degree to which the simulation results from the model can be believed. This in turn helps in making decisions about how little material, and in what configuration, should be used to create elegant, sustainable designs that are unlikely to fail. So validation of computational mechanics models is an essential step in solving the ‘two earths’ dilemma (see post on August 13th, 2012).