旋转机械故障的研究及常见故障的振动诊断毕业课程设计外文文献翻译、中英文翻译

1. 英文文献翻译1.1 英文文献原文题目Chapter 2 Research and rotating machinery fault vibration fault diagnosis of common.Rotating machinery are those main function is to be completed by the rotary movement of mechanical equipment, such as steam turbines, gas turbines, generators, motors, centrifugal blowers, centrifugal compressor pumps, vacuum pumps and a variety of slow growth of the gears and other machinery equipment, all belong to the scope of rotating machinery. Rotating machinery is the application of machinery and equipment most widespread, the number of the largest and most representative one of machinery and equipment, especially in electric power, petrochemical, metallurgy, machinery, aviation, nuclear industry and other industries, rotating machinery is a significant share an important position.2.1 Classification of Rotating Machinery VibrationRotating machinery vibration failure was classified as a major form of failure, according to different classification methods, a variety may be as follows1. By vibration frequency classification (1) Vibration frequency; (2) Harmonic vibration, for example, two octave, 3 octave vibration; (3) The entire baseband frequency scores (such as 1 / 2, 1 / 3, etc.) of the vibration; (4) Frequency and baseband into the relationship between a certain percentages (eg 38% 49%) of the vibration; (5) ultra-low-frequency (vibration frequency 5Hz below) vibration; (6) Ultra-high frequency (vibration frequency in 10 kHz and above) Vibration2. Amplitude direction according to classification (1) Diameter (horizontal) to the vibration that is the direction along the shaft diameter of the vibration is generally divided into horizontal vibration straight vibration. (2) Axial vibration, that is, the direction along the axis of vibration cutting; (3) Tensional vibration, that is, the vibration along the shaft rotation direction.3. by vibration of the reasons for classification (1) The vibration caused by rotor imbalance; (2) Shaft misalignment caused by vibration; (3) Sliding bearing and crankshaft vibration caused by eccentricity; (4) The machine parts caused by loose vibration; (5) Friction (such as seal friction, the rotor and the stator friction, etc.) caused by vibration; (6) Bearing damage caused by vibration; (7) Sliding bearing oil whirls and oil whip caused by vibration; (8) Air power and hydraulic vibration caused by factors such as; (9) Bearing stiffness asymmetry caused by vibration; (10) Electrical aspects of the reasons for the vibration caused by4. Vibration occurred by the site classification (1) Rotor or shaft (including the journal, shaft profile vane, etc.) vibration;(2) Bearings (including the film sliding bearings and rolling bearing) vibration; (3) Shell, bearing vibration; (4) Infrastructure (including aircraft seats, table, or bracket, etc.) vibration; (5) Other areas such as valves, pipe stem, and a variety of structural vibration, etc.In addition, if according to the characteristics and forms of vibration, but also separation of synchronous vibrations (forced vibration) and sub-synchronous (self-excited vibration), etc. Due to vibrations caused by the failure of its manifestations are diverse, in order to accurately identified the cause failures cause - generally speaking, have to rely on signal processing techniques and vibration theory, and other modern methods and means to conduct a comprehensive and integrated analysis and in accordance with the gradual accumulation of experience in the specific circumstances, the only way to achieve fault diagnosis success. Failure of rotating machinery and therefore must be characterized by research. 2.2 The characteristics of rotating machinery fault The implementation of fault in the dynamic monitoring of rotating machinery, we must pay attention to other features:2.2.1 Rotor Features The rotor component is the core of rotating machinery and equipment, which is fixed by the shaft and the installation of various types of circular discoid components (such as coupling, bearings, impeller, gear, balance disk, pulley, wheel, flywheel, etc.), formed. As the entire rotor in high-speed rotation movements, so its manufacture, installation, commissioning, maintenance and management have a very high demand. If you had problems with one of these components, or in connection with a change in part an exception occurred, they immediately drew a strong vibration unit. It can be said of dynamic monitoring rotating machinery monitoring and diagnosis is mainly the rotor state of motion.2.2.2 The frequency characteristics of rotating machinery vibrationMost of rotating machinery vibration signals is periodic signals, quasi-periodic signal, or a stationary random signal. Failure of rotating machinery vibration characteristics have a common point, namely, the failure of their characteristic frequency related with the rotor speed is equal to the rotor rotation frequency (referred to as transfer frequency, also known as frequency) and its octave or sub-frequency. Therefore, the analysis of vibration signals of the frequency and turn the relationship between the frequencies of rotating machinery fault diagnosis of a key.2.2.3 for rotating machinery vibration monitoring the main wayVibration signal analysis is the basic method for monitoring rotating machinery, the main three-pronged approach to obtain monitoring information 1. Analysis of rotating machinery vibration frequency of each type of fault has its own characteristic frequency at the scene to make the frequency of the vibration signal analysis is the diagnosis of rotating machinery of the most effective method. Frequency speed of rotating machinery is like a military demarcation line, the entire band is divided into sub-and super-asynchronous asynchronous vibration frequency of vibration of two sections, to seize this point, helps us to analyze and judge the fault 2. Analysis of amplitude and direction of features in some cases (certainly not all occasions) different types of rotating machinery fault vibration on the performance characteristics of a clear direction. Therefore, the vibration of rotating machinery measurements, as long as conditions permit, the general measure of each measuring point should be horizontal, vertical and axial three directions, as in different directions to provide us with a different fault information. Leakage measured in one direction, you may lose a message. 3. Analysis of the relationship between the amplitude changes with the speed of a considerable portion of rotating machinery fault vibration amplitude and speed changes are closely related, so on-site measurements, when necessary, to create conditions for as much as possible, in the process of changing the speed amplitude measurement of the machine value.2.3 Rotating Machinery Vibration Fault Diagnosis As mentioned earlier, equipment fault diagnosis is essentially a pattern classification are based on test analysis obtained on the state information, and grouped into a certain type of equipment failure. Therefore, the characteristics of each type of fault must have sufficient understanding. Equipment diagnostics development today, the people through a large number of experimental studies and a wide range of diagnostic practice, for a variety of devices (especially rotating machinery) of the failure mechanism, fault type and its characteristics have a considerable understanding of understanding. Statistics show that, with the production of a different nature, the type of equipment used is also different, so the proportion of various types of failures is also inconsistent. Here are several common fault diagnosis of rotating machinery vibration characteristics, diagnostic methods and examples.2.3.1 Imbalance According to the information that various types of rotating machinery failure due to imbalance of about 30%, we can see that the machine rotor imbalance caused by rotating machinery vibration is a common multiple faults. To fully understand and grasp the characteristics and mechanism of unbalanced fault diagnosis is very important. 1. The causes of imbalances caused by rotor imbalance are many reasons, such as: unreasonable because it is designed geometry caused by different heart, or deviate from the geometric center line of rotary valve shaft; Manufacture, installation error; Rotor material uneven, or heat unevenly; Rotor initial bending; Work medium in the solid impurities in the rotor on the uneven deposition; Rotor in the course of corrosion, wear and tear; Rotor parts loose, fall off.2. Rotor imbalance may lead to consequences for the flexible rotor may also generate additional degree of damage due to dynamic inertia of the centrifugal force caused by imbalance. For various reasons caused by rotor unbalance fault is a basically the same pattern. To sum up, the rotor imbalance may lead to the following undesirable consequences: (1) The rotor caused by repeated bending and internal stress, causing the rotor fatigue, even lead to rotor fault; (2) To enable the machine in operation during the excessive vibration and noise, so that it will accelerate the wear of bearings and other components to reduce life expectancy and efficiency of the machine; (3) Through the vibration of the rotor bearings, machine transmits to the base blocks and buildings, resulting in deterioration in working conditions. 3. Rotor imbalance generally include the following four cases (1) Static unbalance; (2) double-sided imbalances; (3) Static and dynamic imbalance; (4) Dynamic imbalance. for example:2-1:Among them, static imbalance is an imbalance in the cross section, while the remaining three kinds of imbalance is an imbalance on the number of sections, and each inspired by a cross-section due to imbalances in the lateral vibration and static unbalance is the same as the mechanism of. In other words, the cross section generated by the phase and amplitude of vibration and its size may vary, but the vibration frequency is exactly the same, are the first-order rotation frequency (fundamental frequency), 2-1f0 - a first-order frequency of the rotor, ie rotor fundamental frequency (Hz); n - rotor speed (r / min). Unbalanced rotor in rotation will produce a cycle of change was the imbalance in power, the cycle just that, as shown in Figure 2-2. With the rotor unbalance vibration signal, its time waveform and frequency spectrum of the typical curves shown in Figure 2-3, and generally has the following characteristics: (1) The vibration signal of the original time waveform of sine wave; (2) The frequency spectrum of vibration signal, its fundamental frequency component and a significant proportion, while other components such as frequency-doubling the proportion of relatively small. (3) In the process of speeding up or down, when (that is, when speed is less than the critical speed), the amplitude increases with the increase in W, both bearing the same direction of the force, while in the later, the amplitude increases with the W, but will decreases, and gradually tends to a smaller valuation. 4. The basic method of diagnosis of unbalanced fault diagnosis of unbalanced faults, we must first analyze the signal frequency components, the existence of transponder prominent situation. Second, look at the direction of vibration characteristics, if necessary, further analysis of the changes in amplitude as speed or measuring the phase. Because the latter two tests carried out too much trouble to stop the problem involved, which in general is difficult in the production of the site done, and only to a non-for not only had to do when, but time can not be delayed too long.2.3.2 Misalignment As the rotor and turn on the sub-shaft connection between the use of connecting devices install properly, or due to bearing centerline deviation, or offset, or because the rotor bending, rotor and bearing clearance and load transfer in the bearing after the deformation and other reasons, tend to result in between the rotor (shaft) to the poor, resulting in vibration and lead to mechanical failure. It is also one of the very common mechanical failures. 1. Shaft misalignment of the shaft does not include the three forms of coupling misalignment and bearing right in both cases, here we only discuss the coupling (shaft) misalignment. Coupling does not usually possesses the following three forms, For example2-4: (1) Parallel misalignment, this time through the rotor axis lines in parallel displacement.(2) The angle misalignment, this time to switch on the two axis lines intersect, or angle displacement. (3) Parallel synthesis misalignment angle, this time two lines intersect the rotor axis of displacement.Figure 2-5 shows the shaft vibration caused by misalignment angle parallel to the simple diagramIn general, the rotor shaft misalignment can cause additional load on the bearings, resulting in the bearing load between the re-allocation would lead to serious bearing damage caused by a strong vibration. On the other hand, with the coupling on both sides of bearing the load changes that may cause the system critical speed of the change in the uneven effects of an increase, giving rise to the coupling fatigue. When the bearing change is large, for the sliding bearing oil film may also cause instability.2. Shaft misalignment of the main features of a typical shaft misalignment radial vibration signal time waveform and frequency spectrum 2-6. And mainly has the following characteristics:(1) The vibration signal of the original time waveform distortion sine wave. (2) The radial vibration frequency spectrum of the signal to a multiplier, and second harmonic components of the main shaft misalignment more serious, and the second harmonic component of the greater proportion, in most cases more than one harmonic component of . (3) The axial vibration of components in the spectrum to octave higher amplitude. (4) Coupling on both sides of the axial vibration is essentially 180 inverting. (5) A typical trajectory for the banana-shaped axis is precession. (6) Vibration on the more sensitive to changes in load, the general vibration amplitude increases with the load increase.2.3.3 Rotor Crack If the rotor rotating machinery are poorly designed (including the improper selection or structure is irrational) or improper processing methods, or the super life of running, it will cause stress concentration leading to cracks. On the other hand, fatigue, creep and stress corrosion can cause micro-cracks in the rotor, plus large change due to the twist and radial load to form the mechanical stress state, resulting in continuous expansion of these micro-cracks eventually become a macro-crack. 1. Three forms of rotor cracks (1) Closed crack. Rotor rotates; the crack was always closed state. When the crack zone in a compressive stress state, would constitute a closed crack, such as the rotor weight is not an unbalanced force smaller or unbalanced force precisely the opposite point to cracks, or uneven quality, moments generated by the rotor is greater than the quality of generated moment and so on. Closed crack little effect on the rotor thrust. (2) Open crack. When the rotor spins, the crack was always open state. Open cracks force the situation is exactly the opposite and closed crack; the crack area is always in tension stress state. Open crack will reduce the stiffness of the rotor, and its stiffness to the different nature of each, so that vibration increased.(3) The opening and closing crack. With the rotation of the rotor movement, crack was open and close alternately state, and generally turn the rotor of each week, the crack will be the corresponding open and closed each time. Crack opening and closing part of the open crack and the crack in the middle of a closed transition state, which is the most complex forms. Figure 2-7 shows the rotor with the opening and closing crack deflection curve diagram. Despite the change in the crack will affect the rotor vibration characteristics, but in most cases is not very sensitive, even the cracks in the rotor has a deep, sometimes hard to find significant changes in the vibration condition. For example, according to theoretical calculations, if there is a change in central depth is equal to 1 / 4 turn on the diameter of the crack, its stiffness is only about 10%, while the changes in critical speed is smaller, only 5%. Therefore, these changes will likely be completely submerged into the other signal, that is, from the observed changes in the natural frequency of the rotor, or when the normal operation of the vibration changes according to the early detection of cracks is very difficult. At present more effective way is to stop the process of measurement and analysis open the rate of change in amplitude. Generally speaking, when there open crack rotor, the rotor will become of all the stiffness of the differences. As a result, the vibration of the rotor with a non-linear nature of the spectrum, in addition to a harmonic component, there are twice, three times to five times the high-harmonic components. Toward the crack, the stiffness of the rotor will be further reduced; a multiplier component, as well as twice or three times or five times, and other first-order harmonic components of the amplitude will be even greater. 2. Be passed on to crack the monitoring and diagnosis is divided into three areas (1) Open, stopping when the variation of amplitude versus speed. (2) The impact of crack depth on the amplitude. Under normal circumstances, th