Implementation of a SQUID-Based NDE System for Detection of Hidden Cracks and Comparison with an Efficient Proposed FEM Algorithm

A 2-D scanning SQUID-Based NDE system for testing of room temperature stationary samples in unshielded environments has been designed and implemented (in SERL Laboratory, http://serl.sharif.edu/). Using our NDE system with white noise level of about 50 μΦ0/Hz-1/2 at 500Hz (in unshielded environment) and with a nonmagnetic 2-D robot, we performed NDE scans of hidden cracks in aluminum sheets. We have also designed a FEM solution algorithm for electromagnetic simulation of the NDE scans. The algorithm divides the whole electromagnetic problem in two more simple problems which results in a great extent saving of commutating memory usage and simulation time. Using these two approaches, it is shown that our experimental results match the simulations very well.