Electromagnetic Characterization of Advanced Composites by Voxel-Based Inverse Methods

The nondestructivecharacterization of advanced composites, such ascarbon-fiber reinforced polymers (cfrp), by electromagnetic means iswell established [6]-[24]. What isneeded to advance the state of the art are sophisticated inversionalgorithms that allow layup and impact damage to be determined inlocalized regions, which means that the more traditional methods ofmodel-based inverse methods must be replaced by voxel-based methods.Thus, one will be able to better distinguish such things asdelaminations from fiber-breakage due to impact damage, or otherparameters thatcharacterize the mechanical state of the cfrp structure, such aselastic modulus and Poisson's ratio on avoxel-by-voxel basis. This information can then be input to damageevolution models. We describetwo such methods, bilinear conjugate-gradients and set-theoreticestimation. The challenge is to extend these methods to anisotropicmaterials. We do that in this project, and will develop thealgorithms for inclusionin our proprietary eddy-current code, \vic, during Phase II.In addition, we continue our program of discovering and exploitingparallelism in VIC-3D(R) to speed up the modeling and processing ofproblems that involve massive data generation.