Under The Mechanical Loads And The Electric Current The Crack Tip's Stress Field And Stress Intensity Factor

In the recent years ,aviation accidents,ship accidents often happen and most of accidents are in virtue of the fractures of wings,landing gears and propellers.All fractures occur because wings,gears and propellers with the mechanical loads during their being used process surpass the stress maxmam.This may bring great damage to the many field . So, how to prevent component's crack extending , is a important task. Using electric heat effect to keep crack within limits is a newly spring up method in recent years. A transient current is guided to a piece of thin conducti- ve plate with a crack. The current concentrates around the crack tip and produces enough heat to keep the crack from extending. In this paper, based on the past theory, from the point of the plate with crack and stress, the distribution of the stress field around the crack tip is derived by theoretical calculation, and the compound stress intensity factor is also derived by two methods. 1.The compound stress intensity factor is derived by adding the heat stress intensity factor and stress intensity factor. 2. The compound stress intensity factor is derived by adding two kind of stress field. Thereby, the compound stress intensity factor in contrast to K1c and determine whether the crack can be expand or not. In same time, by compared the results from the Ansys numerical analogy,the experiment surveys and the theoretical calculations, can prove the result's reliability. So the method proposed here can be applicable in the engineering, and is advanced techniques.