Magnetic shielding property for cylinder with circular, square, and equilateral triangle holes

The shielding property of cylinder with circular, square, and equilateral triangle holes was investigated by finite element analysis (FEA). The hole area ( S hole ) plays an important role in magnetic circuit on the surface of cylinder. When S hole is less than the critical area ( S H ), cylinder with three shapes of holes obtained the same remanent magnetization inside, indicating that the shielding property is unaffected by the shape of the hole. Hence, high-permeability material is the major path of the magnetic field. On the condition of S hole > S H , the sequence of the shielding property is equilateral triangle > square > circular, resulting from magnetoresistance of leakage flux in air dielectric. Besides, the anisotropy of shielding property caused by hole structural differences of the cylinder is evaluated. We find that a good shielding effectiveness is gained in the radial direction, compared with the axis direction. This research focuses on providing a theoretical support for the design of magnetic shield and improvement on the magnetic shielding ability.