Competition between Tensile and Compressive Stresses on Electrical Tree Growth in Epoxy Resin

The electrical tree tests of epoxy resin were conducted by applying compressive stress and tensile stress orthogonal to each other. Results show that the compressive stress is within 15 MPa, and there is competition between compressive stress and tensile stress, which closes the defect and inhibits the electrical tree growth. When the compressive stress is larger than 20 MPa, the shear stress is dominant, there is a cooperative relationship between the tensile stress and shear stress, which opens defects and facilitates the electrical tree growth.