Track treeing mechanism and its application in electrical insulation

Based on electrostriction and fracture mechanics, experimental observation and data processing, two models (restriction among tree tracks and induction of tree tracks onto stress concentrated points) and factors (restriction and induction) are proposed. The existence of four types of plastic zone are pointed out and the development depth regularities and total area of tree tracks in two basic experiments are described by using four basic formulae. A series of turning points are also discovered. The physical meaning of the turning points, the essence of breakdown during electrochemical etching and “water trees”, the fatigue and relation between stress and strain of metal material and the effect of loading mode on crack development are briefly discussed