Vibration measurement tests

In this work, a microwave interferometric method and apparatus for vibration measurements is described. The principle of operation is based on measurement of the phase of reflected electromagnetic wave changing due to vibration. The most important features of the method are as follows simultaneous measurement of tlie magnitude and frequency of the rotating object high measurement accuracy weak influence of the roll diameter, shape and distance to the object under test. Besides, tlie reflecting surface can be either metallic or non-metallic. Some technical characteristics are given. 

During the performance test, unfiltered vibration measurements and a Fast Fourier Transform (FFT) spectrum shall be made at each test point except shutoff. The measurements shall be as follows ... 

The vibration measured during the performanee test shall not exceed the values shown in the following ... 

The pump and driver train, complete with all auxihaties that make up the unit, shall be tested together. When specified, torsional vibration measurements shall be made to verify the vendor s analysis. The complete unit test shall be performed in place of or in addition to separate tests of individual components specified by the purchaser. 

All purchased vibration probes, transducers, and oscillator-demodulators shall be in use during the test. If vibration probes are not fnmished by the vendor or if the purchased probes are not compatible with shop readout facilities, shop probes and readouts that meet the accuracy requirements of API Standard 670 shall be used. The vibration measured with this instrumentation shall be the basis for acceptance or rejection of the pump (see 2.8.3.7 and 2.8.3.8). 

The vibration measured during the performance test shaii not exceed the vaiues shown in the foiiowing ... 

The vibration sensation test is purported to be a quantitative measure of perception of a vibrating stimulus. It is used to see if a person can volitionally tell the examiner when a stimulus is first perceived. It is intended to reveal impairment in the ability of a peripheral nerve to conduct an impulse. If the subject has a high threshold for this test, it is suggested by the amount of time the subject requires for acknowledging his/her perception of the stimulus. This testis subject to embellishment by the examinee and to observer bias by the test administrator. Such impairments detected on screening tests such as this must be correlated with other more objective tests for evidence of peripheral neuropathy such as nerve conduction velocities, tendon reflex responses, and patterns of sensory loss detected by pin prick perception. 

Mechanical compressibility in compression tests is, at least partly, a result of the collapse of an initial open bed structure (supported by cohesive interparticle forces or interparticle liquid bridges), which is totally and irreversibly destroyed. In the case of vibrational tapping tests, the openness of the bed structure can be recovered at least to some extent. Thus, different mechanisms yield different tendencies in the compressibility measured by tapping and mechanical compressibility. 

The thermal conductivity measurement of nanofluids was conducted with the fluid without any vibration. Each test was conducted at ambient condition, and the data were collected for 131 s. After repeated trials it was found that the variable resistor should be balanced slightly above the known resistance of the platinum wire. Once the bridge is properly balanced, the variation of voltage with time was measured and recorded. The measured thermal conductivity data was calibrated using three kinds of fluids. 

During the pre-operational tests of the reactor no vibration measurements were performed on the reactor internals as, at that time, the problem of the internal fatigue failures inside the vessel had not yet become the serious safety problem which in subsequent years it was to become. 

Hydraulic tests to assess the flow distribution and measure vibration of tube bundle are carried out on a 60 degree sector model of SG (fig 13a). The velocity distribution measured in the inlet plenum was found matching with prediction of the 3D hydraulic calculations (fig 13b). Vibration measurements are carried out in the straight spans and expansion bend regions. Although the vibration level is found higher in the inlet span where cross flow takes place across the tube bundle, it is within the acceptable values based on structural mechanics analysis (fig 13c). 

The vibration measurements that had been made during the engineering tests and low-power phases of the programme were repeated. 

Two common types of dynamic tests are the torsional pendulum test and the vibrating reed test shown in Figure 2.10a and b. The first measures a shear response (a dynamic... 

In many industries a non-contact testing of vibrating parts of the various equipment is needed. To prevent the destruction of large aggregates rotating and moving in various directions with the large speed, the parameters of vibrations should be measured very carefully. Besides, vibrations reduce considerably the equipment s duration of life. 

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