Papers by Keyword: Double-Notch

Abstract: The rotating bending fatigue tests have been carried out to investigate the fatigue limit of specimen with double-notch which is constructed by the step and the blind hole, and the effect of stress concentrations at the double-notched bottoms on the fatigue limits are analyzed using three-dimensional elastic finite element method (3D-EFEM). There are fatigue limits of 17 groups on the single-notched specimen and double-notched specimen obtained in the fatigue tests. The stress field interactions are discussed between the stress field by the blind hole notch and the stress field by step using 3D-EFEM. The results obtained in this study are as follows: The fatigue limit of the double-notch specimen is insensitive to the distance between the blind hole and step for the low carbon structure steel with better ductility; while, for the high-strength steel, superposition and intensification of the stress concentration by the blind hole and step mutually may be avoided, and their adverse effects on the fatigue strength may be become to minimal, when taken appropriate distance between the blind hole and step. The results are significant for engineering design of the multi-notched parts, and studying fatigue strength theory.

Abstract: The fatigue limit of parts and components that have the multi-notches is important data for the design and manufacture of machinery and traffic equipment which are operated under the high speed or pressure. In this paper the rotating bending fatigue tests have been carried out to investigate the fatigue limit of specimen with double-notch that is constructed of step and blind hole, and analyzed the effect of stress concentrations at the double-notched bottoms on the fatigue limits, using three-dimensional elastic finite element method. Firstly, the fatigue tests of 8 group specimens have been performed for examining the of fatigue limits of the single-notched specimen and double-notched specimen, respectively. Additionally, the stress field interactions between two stress fields by the blind hole notch and step are discussed using three-dimensional elastic finite element method. The main results obtained in this study are as follows: The fatigue limit of the double-notched specimen are down comparison with the fatigue limit of the single-notched specimen; the fatigue limit of the double-notch specimen is insensitive to distance between the blind hole and step for the low carbon structure steel with better ductility; for the high-strength steel, superposition and intensification of the stress concentration by the blind hole and step mutually may be avoided so that their adverse effects on the fatigue strength may be become to minimize, as take appropriate distance between the blind hole and step. The results are significant for the design of engineering design of the multi-notched parts, and the study of fatigue strength.

Abstract: The stress distributed in the mid-bondline of the joints made of aluminium alloy and an epoxy adhesive was determined with the ANSYS software. The results from the FEA showed that the values of the peak stresses of the all the stress components (including the longitudinal stress Sx, the peel stress Sy, the shear stress Sxy, the 1st principal stress S1 and the von Mises equivalent stress Seqv) distributed in the mid-bondline are changed a little as the notch distance L was increased while the notch depth d was not great than 0.6mm. But the evidently changes occurred when the notch depth d was great than 0.9 mm for the stress Sx, Sy and S1 distributed in both the mid-bondline and the interface of the lap zone. When taken the stress distributed in the middle part of the lap zone into account, the peak stress at the point in the mid-bondline corresponding to the edge of the notch decreased firstly and then increased again as the notch distance L was increased from 0 mm to 8 mm. The proper geometry of the notch in the specimen was chosen by finite element analysis.