Papers by Keyword: Stress Concentration Factor (SCF)

Abstract: In this paper, the elastic stress and strain fields in curved beams of finite thickness with end moments are systematically investigated using 3D finite element analysis. For a curved beam of finite thickness, the through-thickness distributions of the stress and strain concentration factors are not uniform and their distributions are different. The radius of curvature and the thickness of the beam have significant effect on the stress and stain concentrations. The relations of the maximum value and the value at the corner root of surface of the stress and strain concentration factors with different thickness for various radius of curvature are respectively obtained.

Abstract: The stress concentration effect of different corrosion pits is different, the shapes of corrosion pits can be seen as semi-ellipsoidal, the short half axes、long half axes and depth of corrosion are 、 and , through finite element analyze, we can see that the stress concentration factors increase with the increase of , but the stress concentration factors decrease with the increase of .

Abstract: There is so much influence to the fatigue life of the whole structural component from cross-section transition zone radian, and more than 100 times difference is made by different structural details for fatigue life [1]. According to structure and features of variable cross-section strut-and-tie,combing with its’ geometric properties and applied stress ways, at the basis of nominal stress method, the fatigue life of variable cross-section strut-and-tie is analyzed in the paper. Then, transitional zone is improved and fatigue life is analyzed. At last, the improved is compared with previous structure and analysis of Influence of fatigue life from variable cross-section strut-and-tie transition zone radian in theoretical. The conclusions of this paper guide other similar researches.

Abstract: Based on the grouping method and lifting and lowering method, the weld joints of TCS stainless steel such as butt joint and corner joint were experimentally examined to clarify their fatigue properties in axial loading. The probabilistic S-N curves were established from the viewpoint of the survival probability and confidence level, and the stress concentration factors were evaluated by using finite element model. As a result, corresponding to fatigue life of N=2×106, the mean values of fatigue limit for corner joint and butt joint are evaluated to be 162.7MPa and 173.7MPa, respectively. The stress concentration factors for butt joint and corner joint are evaluated to be 1.55 and 2.22, respectively.

Abstract: The purpose of the present study is to propose a new technical method for improving the fatigue life of a panel with big grooves by setting rounded transition structure and stress relief slots in the vicinity of it. The main idea of the method is to reduce the stress concentration at the edges of rounded transition structure. To confirm the effectiveness of the method, analyses were performed by using software for two-dimensional elastic problems based on the body-force method. The calculation results show that the existence of stress relief slots effectively reduced the stress concentration at the edges of rounded transition structure. A close distance between the rounded transition structure and the stress relief groove resulted in a little influence of stress concentration at the edge of rounded transition structure. Also, a lower stress concentration was obtained by increasing the diameter and numbers of stress relief grooves. Results prove the effectiveness and certain engineering practicability of this method. The method is helpful for structure design.

Abstract: High cycle fatigue behavior of the representative cold forging die steel, YXR3 with Rockwell C scale hardness number of 60.0 is investigated. Axial fatigue strength of plane and notched bar specimens with stress concentration factor, Kt of 1.5, 2.0 and 2.5 is presented. The emphasis is placed upon the subsurface crack initiation observed on notched specimens failed at number of cycles over than 106 cycles. Crack initiation and propagation mode of cold forging die steel is discussed with respect to fracture surface morphology.

Abstract: A theoretical model considering the distribution of the grain sizes and grain-boundary ledges was developed for cavity nucleation in creeping ceramics containing viscous grain boundary phase. The critical stress involving the effects of various shapes of cavities and viscosity coefficient (η) for cavity nucleation was presented. Then, the local stress concentration factor concerning different distributions of grain-boundary ledges was calculated and discussed. The results showed that various shapes of cavities and η are not the main influencing factors on the critical stress. The stress concentration factor increases with the increase of grain-boundary ledge size or the density. Therefore, it would be liable to cause cavity nucleation at gain boundary when the density of grain-boundary ledges is high and the size is large.

Abstract: There are close relations between stress concentration factor of notch and stress intensity factor of crack when the boundary conditions and geometrical conditions are in the same. The transition method of geometrically similar element to calculate the stress concentration factor of notch is proposed and some examples are computed by this method. There are some advantages for this method such as no limit of structural dimension, good adaptability, high precision and use convenience.

Abstract: Finite element method (FEM) is used widely for various structural problems. However, in general, it is difficult to guarantee the accuracy of results obtained by commercial software of FEM. In this paper, a practical finite element technique for calculating the stress concentration factors with high accuracy is proposed in consideration of physical meaning of stress concentration, and applied to a 2-dimentional stress problem.

Abstract: The purpose of this study is to define the amount of critical corrosion in steel that causes cracks on the cover of concrete. Major variables in the amount of critical corrosion are concrete strength, thickness, and the cover of concrete. In this experiment, stress concentration is a newly added factor. According to the results of this experiment, it is evident that the amount of critical corrosion decreased according to the increase in stress concentration factors. In addition, electric currents were measured using a constant voltage generator. When a constant voltage was connected to the corrosion circuits, it was discovered that the magnitude in the change was similar to the displacement on the cover of concrete and the electric current according to time.1)