http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Effect of Short-Time Carburizing Treatment on Microstructure and Mechanical Properties of M50 Steel
Yinghua Wei,Xingfu Yu,Shuai Wang,Xiangyang Shen,Wenzeng Zhao,Yong Su,Yu Yang,Xiaochuan Feng 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.6
By using scanning electron microscope (SEM), transmission electron microscope (TEM), X-Ray diffraction (XRD), and hardnessand rotational bending fatigue tests, the effect of short-time carburizing treatment on the microstructure and mechanicalproperties of bearing steel was studied. The results show that when the M50 steel is not carburized, the hardness is 750 HV,the rotational bending fatigue limit is 1100 MPa, and the impact absorption energy is 15.46 J. After short-time carburizationwith the carbon potential of 0.6%, the maximum hardness in the carburized area, the rotational bending fatigue limitand the impact absorption energy are all increased to be 807.7 HV, 1210 MPa and 16.72 J respectively. When the carbonpotential is further enhanced to be 0.8%, the maximum hardness of the carburized area of the steel is further enhanced to be813.4 HV, but the rotational bending fatigue strength and the impact absorption energy are both decreased to be 1125 MPaand 13.65 J respectively, which has close relations with the increasement of undissolved carbides and the precipitation ofacicular carbides.
Research on Nonlinear Vibration Characteristics of Spiral Bevel Gear
Nie Junfeng,Yu Guangbin,Song Ye,Qu Zhigang,Zheng Minli,Zhao Xingfu 보안공학연구지원센터 2016 International Journal of Multimedia and Ubiquitous Vol.11 No.2
Based on the concentrated parameters theory, a 7-freedom coupled vibration dynamic model of the spiral bevel gear transmission system is established, which includes transmission error, time-varying mesh stiffness and the tooth backlash clearance. In the model, the axial vibration, the torsion oscillation of the gear pair aroused by tooth meshing force and the lateral oscillations resulting from flexional deformation of the gear shaft are taken into account. The mesh stiffness fluctuation is developed as 5-order Fourier series and the tooth backlash clearance is fitted by 7-order polynomial function. Through the Gear method, the dynamic response of the system is obtained, and the vibration characteristics are analyzed.
Dynamic Characteristic Simulation of Helicopter Tail Drive Shaft System
Nie Junfeng,Yu Guangbin,Song Ye,Qu Zhigang,Zheng Minli,Zhao Xingfu 보안공학연구지원센터 2016 International Journal of Smart Home Vol.10 No.6
Helicopter with the advantage of light, flexible and hovering in the air, is widely used. In both military and civilian domain, it gets more and more attention. It becomes the main subject of research in the world. In the power transmission system of helicopter, the tail rotor shaft is an important part. It is one of the key technologies to predict the dynamic characteristics of the shaft accurately for improving the overall performance of the helicopter. Based on the theory of elastic mechanics, rotor dynamics and the finite element analysis, the former main drive shaft is taken as an example. The dynamic characteristics of the transmission shaft is calculated by the multi/few degrees of freedom finite element method. The validity of the finite element method with few degrees of freedom is determined. Then the structure characteristics of the helicopter tail drive shaft are analyzed, and the dynamic characteristics of the helicopter tail rotor shaft are calculated by using the finite element method with few degrees of freedom. The research results provide the basis and guidance for the design of the helicopter tail drive system.