Understanding and preventing materials failure By RaĂşl Radovitzky and Andrew Seagraves
Device and system reliability is often determined by the failure response of the material systems involved.
This is particularly relevant in situations involving extreme dynamic loading environments: whether it is the hundreds of micrometeorite impacts the Hubble telescope receives every year, a flock of birds or a piece of tire sucked into a jet engine fan, or an impact-damaged reinforced carbon-carbon heat shield tile expected to protect an atmosphere entry vehicle, we aerospace engineers constantly worry about material and structural failure. We must try to understand how damage nucleates and propagates within materials; for example, upon impact loading, a complex process which can only be pursued via high-fidelity computer modeling and simulation (M&S). The expected role of M&S is to provide mechanistic explanations of the physics involved, which can help in the assessment and optimization of system damage vulnerability in operating as well as under unexpected loading conditions. Yet the accurate modeling of Accurate modeling of dynamic dynamic fracture remains one of the most difficult chalfracture remains one of the most lenges in computational mechanics.
difficult challenges in computa-
Take, for example, the tragic Columbia accident. Perhaps tional mechanics. the main culprit in the decision to return the shuttle to earth was the later-to-be-found incorrect simulation-based assessment of the damage sustained by the heat-shield tiles during blastoff. As it turned out, the simulation tool employed was unable to describe the impact fracture mechanisms of the
Understanding and preventing materials failure
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