Papers by Keyword: Crack Technique

Abstract: The applied investigation of regular fracture for low carbon steel under extra-low cycle inverse rotating bending fatigue was studied in this paper. The principle of inverse rotating bending fatigue was explained at first. The effect of experimental parameters on cycle times of fracture, such as the relations of presetting deflection to quality of blanking and cycle times of fracture were discussed through the experiments. The effects of geometrical parameters of notch, such as tip radius, depth and open angle, on cycle times of fracture were studied. The results show that low carbon steel can be regular fractured through inverse rotating bending fatigue. The quality of blanking is depended on presetting deflection of inverse rotating bending.

Abstract: The application of fracture in three-points bending to blanking of tool steel was studied. Several mechanical models of stress blanking were discussed at first. And then the experiments were made in special equipment of three points bending designed by us. Several problems, such as the effect of wedge on fracture, the effect of support condition on the quality of blanking, the effect of the geometrical parameters of notch on blanking were studied with the help of experiment. The suitable parameters of three-point bending for blanking, depth and tip radius of notch, the ratio of blanking length to the diameter of the bar and suitable support in asymmetrical geometry have been proposed.

Abstract: The application of regular blanking for brass under extra-low cycle rotating bending fatigue was studied. The experiments of rotating bending fatigue have been made in special equipment designed by us. Several problems, the relations of the cycle times of fracture, the strain amplitude near the tip of notch and fracture toughness of fatigue to the presetting deflection, the effects of depth and tip radius of notch to the cycle times of fracture, were discussed through the experiments. The formulae of stress amplitude at the tip of notch and fracture toughness of brass to presetting deflection were obtained. The suitable parameters of fracture in rotating bending fatigue for blanking of brass under extra-low cycle times have been proposed.