共查询到20条相似文献,搜索用时 62 毫秒
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THEORETICAL ANALYSIS AND EXPERIMENTAL VERIFICATION ON TERNARY-WAVES METHOD TO COMPILE ACCELERATED SPECTRA 总被引:1,自引:0,他引:1
Xiong Junjiang Wu Zhe Gao ZhentongAircraft Design Bureau Beijing University of Aeronautics Astronautics Beijing China 《机械工程学报(英文版)》2002,15(4):308-313
The equivalent damage calculation formulae of fatigue crack formation and growth are established. In order tocompile the fatigue crack formation and growth accelerated load spectra, the main wave shapes and load sequence of theactual load spectrum are kept constant, and the carrier waves are cut off. And secondary waves are put together into newsecondary waves to shorten the test time according to the equivalent damage calculation formulae respectively. Then bythe fatigue cumulative damage calculation of the fatigue crack formation and growth accelerated load spectra, the onecorresponding to the bigger damage is determined as the fatigue accelerated test load spectrum. Therefore in the test process, the fatigue accelerated test spectrum may be applied till fatigue failure, the engineering fatigue crack length of full-scale structure need not be inspected, and the fatigue crack formation accelerated load spectrum need not be transferredinto the fatigue crack growth accelerated load spectrum. Finally, it 相似文献
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《机械工程学报(英文版)》1997,(3)
THEORETICALANDEXPERIMENTALSTUDYONMAGNETICFLUIDSEALINGOFSERRATEDFORMLiDecai,SongDengxuan,YuanZuyiNorthernJiaotongUniversityAbs... 相似文献
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《机械工程学报(英文版)》1997,(1)
INVESTIGATIONONCOMPRESSIBILITYANDBULKMODULUSOFFLUIDCaoBinggangXi'anJiaotongUniversityAbstractTheproblemsinthetraditionaldefin... 相似文献
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Huo Rui College of Mechanical Engineering Shandong University Jinan China Shi Yin College of Power Engineering Naval University of Engineering Wuhan China 《机械工程学报(英文版)》2005,18(2):246-250
In view of difficulties concerned with direct measurement of excitations inside source equipments and their significant influence on vibration isolation effectiveness, a dynamical model, for vibration isolation of a rigid machine with six-degree-of-freedom mounted on a flexible foundation through multiple mounts, is analyzed, in which the complicated and multiple disturbances inside the machine are described as an equivalent excitation spectrum. And a method for the estimation of the equivalent excitation spectrum according to system dynamic responses is discussed for the quantitative prediction of isolation effectiveness. Both theoretical analysis and experimental results are demonstrated. Further work shows the quantitative prediction of transmitted power flow in a flexible vibration isolation experiment system using the proposed equivalent excitation spectrum method, by comparison with its testing results. 相似文献
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EXPERIMENTALINVESTIGATIONOFPASSIVECONTROLONUNSTABLECHARACTERISTICSINAXIALFLOWFAN①LiangXizhiWuHaiChineseAcademyofSciencesAbstr... 相似文献
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Inconel 718 is a typical difficult-to-machine material, and its high speed end milling process has wide applications in manufacturing parts from aerospace and power industry. Surface integrity of these parts greatly influences the final characteristics. This paper presents an experimental investigation to evaluate surface integrity behaviors in high speed end milling of Inconel 718 with finishing cutting parameters in terms of surface topography, surface roughness Ra, residual stresses, subsurface microstructure, and microhardness. The results show that abraded marks can be observed on the machined surfaces, and high cutting speed is advisable to get better surface topography and roughness quality. Due to high cutting temperature, residual stress is mainly high tensile stress. After increasing the cutting speed beyond 80m/min, the cutting forces hardly increased and the chips take away more cutting heat, which leads to that the residual stress barely increases. Microstructures in subsurface layers have only slight deformations after high speed milling, and there was also no obvious difference when the cutting speed increased beyond 80m/min against the microhardness in subsurface increases together with the cutting speed. 相似文献
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FINITEELEMENTANALYSISANDEXPERIMENTALSTUDYOFTHEMETALMULTIDIEIRONINGPROCESSFINITEELEMENTANALYSISANDEXPERIMENTALSTUDYOFTHEMETALM... 相似文献
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《Mechanical Systems and Signal Processing》2000,14(4):571-577
In this work, we address the influence of period variation on the Westland CH-46E helicopter vibration data. The estimation of the time-varying shaft speed by using a newly developed constrained AR(2) estimator and the well-known EKF estimator will be discussed. The influence that the period variation captured by these two estimators have on the periodic time–frequency analysis will be illustrated via numerical simulation. This simulation clearly illustrates a potential spectral smearing if the period variation is not properly accommodated. A data resampling scheme will then be proposed to eliminate the spectral smearing effect. The potential of this scheme will be demonstrated via the analysis of the helicopter vibration data. 相似文献
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HuXinXi JuntongJin YeInstitute of Computer Integrated Manufacturing Shanghai Jiaotong University Shanghai ChinaGu Dongyun Dai KerongDepartment of Orthopaedics Shanghai th People''''s Hospital Shanghai Second Medical UniversityShanghai China 《机械工程学报(英文版)》2003,16(3):309-312
Former research work about the modeling of hip joint focus on the upper segment of femoral, and assumes the acetabulum cup is sphere concave, and the acetabulum prostheses is semisphere. A method of acquiring the point data on the surface of the hipbone using the reverse engineering technology is presented. After analyzing the acetabulum surface fitting error, a rotation ellipsoid CAD model is applied to fit the acetabulum surface, and then optimization technique is used to find the geometric parameters of the model. The fitting error between the sphere and rotation ellipsoid is compared and gets the result that the fitting error of rotation ellipsoid is smaller than sphere, and the rotation ellipsoid can describe the shape of the acetabulum better. 相似文献
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《Mechanical Systems and Signal Processing》2002,16(2-3):273-284
This study grew out of the use of vibration to modify welding stresses, and the corresponding need to understand the modal vibration properties of the test structures. Supporting the structure is a practical problem in experimental modal analysis. In this study the effect of the supports on the dynamic properties of a lightweight structure were investigated. Thick rubber bungee supports and thin elastic band supports were used in the investigation. The effect of the position of the supports was found to be insignificant if a proper type of support is used. It was observed that with the thick bungees the modes become invisible or obscure on the frequency response function (FRF) curves. On the other hand, the thin elastic band supports provide very clear FRF curves and hence clear mode shapes. It has been suggested that the bungees should be chosen considering the weight of the structure and the requirement of the vibration amplitude in the modal analysis and/or in the subsequent treatments. The position of the bungees should be chosen at the node points of a particular mode of the structure to reduce the support effects further. 相似文献
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多跨转子-轴承系统振动稳定性试验研究 总被引:7,自引:1,他引:6
在一多跨转子-轴承模拟试验台上进行了轴承不对中对系统阻尼及稳定性影响作用的试验研究。采用扩展Prony方法识别了阻尼参数,从非线性系统动力学角度对试验中若干现象进行了定性分析。 相似文献
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Zhang Junhong School of Mechanical Engineering Tianjin University Tianjin China Sun Shaojun Weichai Diesel Power Co. Ltd. Weifang China 《机械工程学报(英文版)》2005,18(2):220-223
A non-linear dynamic model of one type of high-speed rotor system with gas supporting system is set up. The laws between the capacity force and the parameters of bearing, the static equilibrium position and rotating speed are studied on the basis of above model. Then, the failure rotating speed is given in the working state, and the relation between the minimum failure rotating speed and clearance of bearing is also studied. At last, the stability and failure condition are discussed in different working conditions. 相似文献
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转子-轴承系统稳定性灵敏度分析的广义能量法 总被引:2,自引:0,他引:2
讨论了转子一滑动轴承复合系统中,各轴承及转子的稳定性对其复合系统的稳定性的影响和作用问题。运用大系统稳定性的理论和方法,为各滑动轴承和转子子系统及其集结系统引入了反映其各自稳定性状态的“广义能量”──李雅普诺夫函数。并在此基础上首次导出并定义了各子系统对其集结系统的灵敏度,用以刻划它们对复合的转子一轴承系统运动稳定性的影响大小。给出了实例以验证定义的正确性和方法的实际应用。 相似文献
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单盘含裂纹转子系统的非线性响应分析与实验研究 总被引:2,自引:0,他引:2
建立含裂纹Jeffcott转子的动力学运动方程。针对裂纹深度对转子系统动态响应的影响及转子盘摆振响应的特点进行仿真计算和试验研究。数值仿真表明,对于较浅的裂纹,系统响应为周期性运动,在某些转速下会出现倍周期运动,同时还出现各种倍频分量。此时的摆振运动常包含激振频率的倍频成分。当裂纹较深时,盘的摆振运动与横向振动都会出现各种非协调响应。试验结果表明,当轴上存在裂纹时,盘的横向振动响应和摆振响应中都会出现高次谐波分量,这些分量虽然从频率成分上讲是相同的,但各分量的大小有明显差异。这些结论对于转子裂纹故障的监测与诊断具有新的意义。 相似文献
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