Virtual fracture testing of composite materials and structures

The burden of testing to prove the safety of structures uponwhose integrity human lives depend is immense: a typical large airframe, for example, currently requires ≈ 104 tests of material specimens, along with tests of components and structures up to entire tails, wing boxes, and fuselages, to achieve safety certification. This cost has to date been unavoidable: while computational stress analyses provide good predictions in the elastic regime, they have not previously achieved predictive accuracy in the presence of damage and fracture. This limitation is starting to be overcome by new modeling strategies, which combine advances in the generality and physical realism of damage formulations with new experimental techniques for probing the physics of failure at the micron and nanometer scales. Along with the ever-increasing power of digital computers, these research advances are making possible virtual tests of such high fidelity that they can be substituted for many of the experiments currently necessary for materials design and certification. Instead of an actual test, the mechanical behavior of a structure up to