A pipeline approach to developing virtual tests for composite materials

A multi-disciplinary project combines experiments and theory to build high-fidelity virtual tests of composite materials. The virtual test is assembled via a "pipeline" running through a number of collaborating institutions. Key experimental challenges are acquiring 3D data that reveal the random microstructure and damage events at high temperatures in the interior of the composite with very high resolution (̃ 1 μm). Key theoretical challenges include representing the stochastic characteristics of the 3D microstructure, modeling the failure events that evolve within it, and developing efficient methods for executing large ensembles of stochastic virtual tests. To begin, 3D images of 3D woven ceramic composites are captured by x-ray μCT on a synchrotron beamline. The statistics of the shape and positioning of the fiber tows in the 3D architecture are used to calibrate a generator that creates virtual specimens that are individually distinct but share the statistical characteristics of measured specimens. Failure of the virtual specimens is simulated by advanced computational methods, revealing the complete failure sequence of multiple interacting crack types. Validation of the analytical methods is performed by comparing with data captured at 1500°C and above, using digital image correlation or μCT to track damage evolution.