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The boundary element method (BEM) is an efficient way to compute solutions of eddy current nondestructive evaluation (NDE) problems. However, in boundary element analysis of eddy currents, the computational accuracy and efficiency depend on the element discretization employed and are very sensitive to the liftoff distance and the relative geometry size between the detecting coil and object under evaluation or test. In this paper, the skin depth parameter is applied to study the element discretization effects on boundary element analysis for 3D eddy current NDE problems. The element discretization rules are concluded by conducting numerical experiments for different liftoff distances and relative probe sizes so that they can be adjusted to account for variations in these parameters, and validated against the analytical method, semi-analytical method, and experiments of some benchmark problems. With the help of the rules, the overall computational accuracy is improved while the cost is reduced for the BEM modeling of eddy current NDE problems.

Electromagnetic compatibility (EMC) compliance to transient conducted immunity (CI) tests is required for automotive electronic/electrical systems. An example is the CI 220 test that employs the transient pulses which are generated by relay contact arcing during switching of an inductive load. To realize compliance with minimum efforts, apposite but simple modeling that enables evaluation at early product design phase is therefore desiable for the EMC engineers to avoid failures in advance. In this paper, as an extension of our previous work, an improved circuit modeling method is developed to fully encompass all the operating modes specified in the CI 220 test by combining of the simulation of both contact arcing phenomenon and stochastic contacts opening and closing process. Experimental validation of the developed model using a non-linear load is also demonstrated. The proposed method is featured by its easy-to-implement without requiring numbers of information on arc dynamic physics.

This letter reports on a fully conformal square-patch frequency-selective surface (FSS) consisting of liquid metal alloy embedded within a flexible silicone elastomer. The flexible and elastic nature of the FSS provides high conformity to doubly curved surfaces. The transmission properties of the FSS on both singly and doubly curved surfaces are studied. This FSS can facilitate electromagnetic interference reduction in the X-band frequency range when wrapped on cylindrical or spherical radomes over dipole-like antennas, thus surpassing many existing flexible FSS technologies that usually allow conformable contact only with singly curved surfaces.