oalib
Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
Vibration Fatigue Analysis of Two-stroke Free Piston Engine Using Frequency Response Approach
Md. Mustafidzur Rahman,Ahmad Kamal Ariffin
Jurnal Kejuruteraan , 2008,
Abstract: This paper describes a vibration fatigue analysis techniques to predict the fatigue life using the frequency response approach. The life prediction results are useful for improving the component design at a very early development stage. The finite element modelling and frequency response analysis have been performed using the finite element analysis software. In addition, the fatigue life prediction was carried out using both the time domain and frequency response method. From the results, it is observed that the Dirlik method gives the best comparable results pseudo-static time domain approach with the frequency response techniques. This paper also describes how this technique can be implemented in the finite element environment to rapidly identify critical areas in the structure. This approach is capable of determining premature products failure phenomena. Therefore, it can reduce time to market, improve product reliability and customer confidence.
风机叶片疲劳加载振动频率特性分析与试验
Analysis on Coupling Vibration Frequency Characteristics of Wind Turbine Blade Rotating Fatigue Loading System
 [PDF]

廖高华,乌建中,张磊安
- , 2016, DOI: 10.16450/j.cnki.issn.1004-6801.2016.06.008
Abstract: 秦世强,康俊涛,周旺保
In light of the characteristics of coupling vibration in the wind blade fatigue loading process, a dynamic blade fatigue loading system model block driven by a rotating eccentric was established. An electromechanical coupling mathematic model was derived using the Lagrange equation. The system dynamics equations were approximate analysis by using the averaging method, then the torque balance equation of vibration was obtained. Based on analysis of the variation in vibration frequency, the simulation model was established. Numerical simulations on the system frequency capture process, and revealed the characteristics of a self synchronous vibration system. Finally, the correctness of the mathematical model and simulation results was verified by the wind blade fatigue loading. The results showed that the blade frequency and vibration amplitude fluctuation when the deviation between the driving and natural frequencies of the blades was obviously large. The frequency deviation in a small range (0.47~0.62 Hz), eccentric rotary system and blade will appear in frequency capture, and then amplitude tended to be stable, but decreased. When the load torque was larger and the motor power was insufficient, the eccentric block will rotate speed jump.
吊挂随机振动疲劳影响因素分析
Effect Factor Analysis of Random Vibration Fatigue of Missile Hanging
 [PDF]

罗杨阳,倪樵,陈铎民,张翼
- , 2016,
Abstract: 根据结构随机振动疲劳寿命的频域分析方法,采用有限元方法计算了某型导弹吊挂的随机振动疲劳寿命,同时研究了吊挂的结构参数对振动疲劳的影响。首先计算了结构的不规则系数;然后定量分析了不同结构参数对疲劳寿命的影响;最后为了研究平均应力对随机振动疲劳寿命的影响,采用Goodman准则推导了结构的平均应力修正系数。研究结果表明应力响应标准差是影响吊挂振动疲劳寿命的主要因素;材料参数和模态阻尼对吊挂的疲劳寿命有着较大的影响;平均应力对疲劳寿命的影响也不容忽视。
In this paper, the fatigue damage of missile hanging under stochastic excitation is calculated with the finite element method, and the effect factors of the fatigue are also analyzed. First, the irregular factors and the root mean square (RMS) stress are calculated with the power spectral density method. Then the effects of the material parameters and modal damping of the structure are evaluated by random vibration analysis. At last, the mean stress correction coefficient is deduced with the Goodman method. The results show that the standard deviation of the stress responses is the principal factor that affects the fatigue life of missile hanging; material parameters and modal damping of the structure also influence the fatigue life to some extent; in addition, the effect of the mean stress cannot be ignored
含多条裂纹梁的模态与振动疲劳寿命分析
Analysis of Mode and Vibration Fatigue Life of Beam with Multiple Cracks
 [PDF]

马一江,陈国平
- , 2017, DOI: 10.16450/j.cnki.issn.1004-6801.2017.02.016
Abstract: 基于Paris公式,提出了一种含多条裂纹梁疲劳寿命预估的方法。在模态分析中,基于传递矩阵方法,利用质量的弯曲弹簧等效裂纹,提出一种求解含有多条裂纹梁固有振型的方法,分析裂纹数目、裂纹位置、裂纹深度对裂纹梁固有频率的影响。在振动疲劳分析中,研究了在简谐激励作用下裂纹数目对裂纹尖端应力强度因子的影响。通过Paris疲劳裂纹扩展方程和同步分析法,考虑裂纹梁振动与裂纹扩展的相互作用,分析了裂纹数目和裂纹位置对裂纹梁疲劳寿命的影响。结果表明,裂纹数量、裂纹位置和深度对梁的模态参数和疲劳寿命有重要影响。
An analytical method is proposed to predict the fatigue life of the beam with multiple cracks based on the Paris equation.In the modal analysis process, the segment of cracks is replaced with bending springs, a new method for solving natural modes of the beam with multiple cracks is proposed based on the transfer matrix method, and the effect of the number, locations and depths of cracks on the natural frequency of the cracked beam is analyzed. In the vibration fatigue analysis, the effect of the number of cracks on the crack-tip stress intensity factor under harmonic excitation is analyzed. Considering the interaction of cracked beam vibration and fatigue crack growth, the effect of the number and the location of the cracks on the cracked beam fatigue life is analyzed based on timing analysis and Paris equation. The results indicate that the number, locations and depths of cracks have important effects on the modal parameters and the fatigue life of the structure.
重型牵引车后桥振动疲劳分析及试验研究
Vibration Fatigue Analysis and Experimental Study of Heavy Duty Truck Rear Axle
 [PDF]

张志远,刘玉梅,陈涛,范文峰
- , 2018, DOI: 10.15918/j.tbit1001-0645.2018.03.008
Abstract: 为提高重型牵引车后桥结构耐久性能,解决冲焊结构后桥推力杆上支架、后盖焊缝、直焊缝等容易发生疲劳破坏等问题,将冲焊桥替换成铸钢桥,通过仿真和试验相结合的方法对比冲焊桥和铸钢桥结构耐久性能指标,建立车桥虚拟实验台,并通过对比试验校核虚拟实验台模型.应用振动疲劳分析方法求解铸钢桥和冲焊桥的疲劳寿命,并用疲劳台架试验验证仿真结果.仿真和试验结果一致,表明铸钢桥壳的疲劳耐久性能要强于冲焊桥壳的疲劳耐久性能,采用铸钢桥的重型牵引车可有效提高结构可靠性.
To improve the durability of heavy tractor rear axle,the durability problem,such as rod-bracket failure,welding line and straight seam-weld crack was focused to be solved.Attempting to replace the welded axle with cast steel axle,several projects were carried out including the durability comparison between cast-steel axle and welded axle,the development of a virtual test platform for vehicle axle,and the virtual-test model examination by contrast experiment.A vibration fatigue analysis method was applied to solve cast-steel axle and welded axle life,and the bench test was taken to verify the simulation result.The simulation and test results identically show that the cast-steel axle is better than welded in fatigue life,the heavy tractor assembled with cast-steel axle can improve its structure reliability effectively.
A Study on the Fatigue Properties of the Spot Welded Components Under the Vibration Environment
振动环境下点焊元件的疲劳特性研究

Xiong Junjang Fei Binjun Liu Wenting,
熊峻江
,费斌军

实验力学 , 1993,
Abstract: In this paper,the fatigue experiment principle,method and process of the spot welded components under the vibration environment are introduced;some experiment results that are the reflections of some of their fatigue properties are presented.The mech- anism of the vibration fatigue destory is discussed and analysed.At last,the p-s-n curve of the crack initiation and the p~*-s~*-n~* curve of the fracture are given,by use of which the service life assessment and the durability analysis are able to continue.
基于非线性累积损伤的随机振动疲劳寿命分析
Random Vibration Fatigue Life Analysis Based on Nonlinear Cumulative Damage
 [PDF]

王虎,王轲,赵丽茹
- , 2018, DOI: 10.16450/j.cnki.issn.1004-6801.2018.05.018
Abstract: 预测承受随机载荷结构件的疲劳寿命是一个复杂的问题,应用Miner线性损伤准则经常会得出偏于冒险的寿命预测。非线性累积损伤理论考虑了加载顺序对疲劳寿命的影响,精度更高,但计算繁琐,且未能用于频域寿命计算。文中给出了一种基于非线性累积损伤的随机振动疲劳寿命分析方法,该方法将频域疲劳寿命的预估结果平分为若干段,考虑顺序效应对每一段结果进行修正并叠加,得到修正的振动疲劳寿命结果,通过简单试验件试验验证了该方法的准确性,对于某加筋板结构在动力学准确建模、多轴应力等效的基础上进行寿命估算,结果证明了方法的有效性和工程可用性。
problem to predict the fatigue life of structures subjected to random loads. The simplest and most widely used damage model is the Miner's linear damage criterion. However, the application of this criterion often leads to the risky life prediction. Nonlinear cumulative damage theory takes into account the effect of loading sequence on fatigue life, with higher accuracy, but it is cumbersome and can not be used for frequency domain life calculation. In this paper, a modified algorithm of frequency domain fatigue life prediction based on nonlinear cumulative damage is presented. The accuracy of the algorithm is verified by simple test. For a stiffened plate structure with accurate dynamics modeling, the validity of the method and the engineering usability are proved.
Chaotic Vibration Analysis of the Bottom Rotating Drill String  [PDF]
Qilong Xue,Ruihe Wang,Feng Sun,Zhiyuan Huang
Shock and Vibration , 2014, DOI: 10.1155/2014/429164
Abstract: Drill string vibration is a widely studied topic. This paper developed a real-time measurement system near the drilling bit and extracted the lateral vibration, longitudinal vibration time series of bottom rotating drill string. In order to reconstruct the phase space, we estimated the delay time with mutual information and calculated the embedding dimension through Cao’s method. Finally, the chaotic characterization of the system is analyzed by calculating the correlation dimension and the largest Lyapunov exponent. The results show that such system can exhibit positive finite-time Lyapunov exponents and a clear convergence toward the correlation dimension, which is a strong indicator for the chaotic behavior of the system. It is expected that the new dynamics found in this paper could be of potential implication to the control methods of the drill string vibration. 1. Introduction In oil and gas drilling engineering, the well is created by drilling a hole 5 to 50 inches (127.0?mm to 914.4?mm) in diameter into the earth with a drilling rig that rotates a drill string with a bit attached. In the process, severe drill string vibration is a major contributor to downhole tool failure. It may also cause hole damage and increase the need for more frequent rig repair. Typically, the drilling string vibration can be divided into three types or modes: lateral, longitudinal, and torsional. The destructive nature of each type of vibration is different. Lateral and longitudinal vibrations of the drill string have been undertaken extensive research since it proposed from mid-1960s, The main reason that caused the fatigue failure of the bottomhole assembly (BHA) [2] was considered to be the vibration of the drill string. Many studies of the drill string focused on the determination of natural frequencies [3, 4], bending stress calculation [5, 6], stability analysis [7], lateral displacement prediction [8], and so forth. Spanos et al. [9] established the finite element model of drill string lateral vibration and analyzed nonlinear random vibration. Chunjie and Tie [10] obtained the natural frequency of drill string longitudinal vibration from a finite element model. Vibrations of all three types (lateral, longitudinal, and torsional) may occur during rotary drilling and are coupled. Single vibration model cannot well describe the dynamics of BHA; furthermore, to establish a precise bottom hole kinetic theory model is difficult to achieve because of the underground complex situation. Additionally, the process of drill bit break rocks is a nonlinear process which is
Vibration Analysis Of a Self-Excited Elastic Beam
Barrón-Meza, M. A.;
Journal of applied research and technology , 2010,
Abstract: the vibration behavior and the energy exchange among the normal modes of a clamped-free self-excited elastic beam are analyzed in this work. to model this kind of beam, the damping term of a van der pol oscillator is directly added to the equation of a linear elastic beam, yielding a single nonlinear partial differential equation. to solve this equation, a spectral method is employed. three vibration modes are considered in the analysis, and the values of the self-exciting constant are varied in order to cover from linear to nonlinear vibration behavior. multiple frequencies of the nonlinear beam are determined through the power spectral density of the beam free-end time series. given that this relatively simple model mimics at least in a qualitative way some key issues of the fluid-structure problem, it could be potentially useful for fatigue studies and vibration analysis of rotating blades in turbomachinery.
Vibration Analysis Of a Self-Excited Elastic Beam
M. A. Barrón-M
Journal of applied research and technology , 2010,
Abstract: The vibration behavior and the energy exchange among the normal modes of a clamped-free self-excited elasticbeam are analyzed in this work. To model this kind of beam, the damping term of a van der Pol oscillator is directlyadded to the equation of a linear elastic beam, yielding a single nonlinear partial differential equation. To solve thisequation, a spectral method is employed. Three vibration modes are considered in the analysis, and the values of theself-exciting constant are varied in order to cover from linear to nonlinear vibration behavior. Multiple frequencies ofthe nonlinear beam are determined through the power spectral density of the beam free-end time series. Given thatthis relatively simple model mimics at least in a qualitative way some key issues of the fluid-structure problem, it couldbe potentially useful for fatigue studies and vibration analysis of rotating blades in turbomachinery.
Page 1 /100
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.