Test method

 

In domain of project vibration test, test method and method are varied, but the measurement technique that presses all sorts of parameter and the physical quality that measure a process will divide, can divide 3 kinds.

 

Mechanical

 

the project oscillatory parameter is changed into mechanical signal, after magnifying via mechanical system again, undertake metrical, record, commonly used instrument has lever type to measure Zhen Yi and Gaigeer to measure Zhen Yi, the frequency that it can measure is inferior, precision is poorer also. But go to the lavatory relatively simply when the spot checks.

 

Optical type

 

the parameter of project vibration changeover is optical signal, after magnifying via optical system, show and record. If reading microscope and laser measure Zhen Yi,wait.

 

Report is measured

 

the project oscillatory parameter is changed into telegraphic date, after classics electron circuitry magnifies, show and record. The point that report measures a way depends on measuring mechanical vibration changeover to be n first (electromotive force, charge, reach other n) , undertake metrical to n again next, get metrical machine is measured what wanting thereby. This is the measurement technique that uses the most extensively at present.

 

Although each are not identical,the content reason of 3 kinds of afore-mentioned measurement technique pledges, but, compositive measurement the system is basic and same, they include Shi Zhen, measure enlarge circuit and indication record 3 link.

 

1, pick up brace up link. Change the mechanical and oscillatory volume that is measured those who be machinery, optical or electric signal, the parts of an apparatus that completes this changeover work makes sensor.

 

2, slotted line road. The sort of slotted line road is very much, they are in the light of the commutation principle of all sorts of sensor design. For instance, the slotted line road that matchs sensor of the type that suppress report only has voltage amplifier, charge amplifier to wait; In addition, still device of road of seamark of integral circuitry, differential circuitry, filter, normalization is waited a moment.

 

3, signal analysis and show, record link. From the voltage signal that slotted line road outputs, can input signal analyzer by metrical demand or carry indication instrument (wait like electronic volmeter, oscillograph, phase meter) , record equipment (wait like recorder of recorder of radial oscillograph, tape, X—Y) etc. Also can be in record when necessary go up in tape, next reintroduce undertakes to signal analyzer all sorts of analysises are handled, get final result thereby.

 

 

Receive a principle

 

Oscillatory sensor is one of crucial parts in test technology, its action basically is will mechanical quantity is received come down, change for to it proportionate n. Because it also is a kind of Electromechanical,change unit. So we also say it waits for transducer, Shi Zhenqi sometimes.

 

Oscillatory sensor is not direct will primitive the mechanical quantity change that should measure is n, however will primitive the mechanical volume that should measure is measured as the input of oscillatory sensor, receive a part to try to receive by machinery next, form another to agree with the mechanical quantity of commutation, alternate by Electromechanical the part is commutation n again finally. The character of service that because the character of service of this one sensor is,receives part and Electromechanical commutation share by machinery will decide.

 

1, opposite type machinery receives a principle

 

Because mechanical movement is the simplest form that material moves, because this people thinks of is to use mechanical method to measure vibration first most, make thereby gave mechanical to measure Zhen Yi (if Gaigeer measures Zhen Yi,wait) . The machinery of sensor receives a principle to build what go up in this foundation namely. The job that measures Zhen Yi relative to type receives a principle is when be being measured, secure the instrument on immobile bracket, make touch lever and the oscillatory direction of the object that be measured to agree, the stretch strength that lends bedspring and surface of the object that be measured are conterminous touch, when the object is oscillatory, touch lever to follow it moves together, the displacement that drives record shaft to depict an oscillatory object on mobile punched tape follows the metabolic curve of time, according to this record curve can be calculated the parameter such as the size that gives displacement and frequency.

 

 

From this knowable, opposite type machinery receives the result that measures partly is the object that be measured relative to the opposite vibration at referenced body, when should consulting body is not moved absolutely only, ability measures the absolutely vibration that gets the object that be measured. Such, produce a problem, what measure when need is absolutely vibration, but when cannot finding immobile reference point again, this kind of instrument does not have the ground of use force. For example: The vibration of diesel locomotive checks on the diesel locomotive of travel, the oscillatory …… of the ground and building is measured when the earthquake, nonexistent an immobile reference point. Below this kind of circumstance, we must measure Zhen Yi to undertake metrical with what measure way another kind, use inertial type to measure Zhen Yi namely.

 

2, inertial type machinery receives a principle

 

Inertial type machinery measures Zhen Yi brace up when, it is to will measure Zhen Yi to be secured directly be being measured of oscillatory object measure a dot to go up, when sensor crust follows object of the vibration that be measured to move, by the property of be used to of stretch bearing gauge block general and crust produce opposite motion, the amplitude of relatively oscillatory displacement that installs the record pen on qualitative gauge block to be able to record next quality component and case, use the relation of the relatively oscillatory displacement of gauge block of property of be used to and crust next, the absolutely and oscillatory displacement that can beg an object that be measured is undee.