In issues linked to forced vibration, Operating Deflection Shapes serve as an excellent tool in resolving such problems. These are utilized for the visualization process of the pattern of vibrations occurring in a structure. The process of measuring vibrations is done at different degrees of freedom or the directions and points of the structure. Forced vibration is usually caused by several factors including external loads, unbalances and forces generated internally.
Key Facts about Operating Deflection Shape Analysis
Operating Deflection Shape Analysis or ODS is effective in visualizing a piece of equipment’s vibrating pattern, which is impacted by its operating forces. This technique incorporates an analyzer that is equipped with every necessary component in recording the equipment’s dynamic behavior, as well as the mechanical structure to determine any existing problems.
Moreover, ODS provides a visual image of the pattern of vibration of the equipment, and this is presented in real-time while the machine is in operation. The phase measurements, as well as the vibration pattern, are all recorded and analyzed. There are also several 3D formats used in presenting the pattern. ODS analysis shows the structure’s movement in a more in-depth manner, and this motion is caused by the forces applied to the exterior and the interior portion of the machine. Thus, ODS is indeed an outstanding method for resolving problems with forced vibration.
Test Involved in ODS Analysis
There is a specific test procedure involved in operation deflection shape analysis, which is the acquisition of information about the mechanical system’s phase and displacement at a certain frequency. The procedure is usually conducted as the machine is being used, and single or multi-channel ODS test may be applied.
Initially, the ODS model is developed, and this is supposed to represent the data. It is important that the data points’ location and number in the ODS model are enough to present the mechanical system’s deformation features. Otherwise, having the incorrect number of the different data point location can result in inaccuracy in the ODS animation, which only provides the wrong information that will not resolve any existing issues.
To obtain the accuracy in the ODS animation, it is important that the data gathered about the vibrating mechanical structure is complete. Furthermore, there should be a thorough understanding and knowledge of the system’s structural dynamics. The level of understanding obtained after conducting the initial vibration test results is essential to achieving success in the test procedure.
For experienced professionals in ODS analysis, they should be able to gather sufficient data as they could, as this could facilitate the accuracy of the test. In addition, the fact that the test is done during the operation of the equipment, there should be ample time devoted without impacting the machine’s productivity.
Single Channel Vs. Multi-Channel ODS Test Procedure
Both of these procedures are useful in gathering information, and they both require careful attention to obtaining and recording data to promote accuracy in the results. During a single-channel ODS test, the animation depends on the specific amount of response that is achieved in a vibration measurement. The tach signal is responsible for providing phase information, and this component is positioned on a rotating shaft that moves at a speed based on the desired animation. To achieve response data, the transducer is used, which is moved to the different data points in the mechanical structure.
All of the orthogonal directions must be taken into consideration when gathering vibration data. With this in mind, ODS animation’s total degrees of freedom should be thrice the amount of data points in the model used. Both the phase and vibration are gathered in each of the degrees of freedom. Afterward, an ODS software program is used as a place to enter the data, as this could help create the accurate animation of the equipment’s deflected shape.
As for the multi-channel test, this depends on the curve fit of the vibration’s magnitude, which is found in different locations in the mechanical system. This should relate to the vibration’s magnitude at one reference point. There is also no need for a tach signal in this type of test procedure. With multi-channel test procedure, there is no impact on the animation’s accuracy regardless of the variation in the vibration that arise during the test. This is because the ODS depends merely on the vibration’s relative magnitude that exist between the reference and response transducer.
Single channel ODS is usually restricted to the mechanical system’s response animation at the shaft’s rotational frequency where analysts receive the reference signal. However, with multi-channel test, ODS animations are generated no matter what the frequency, as long as it is within the analyzer’s noted frequency range. This makes it more ideal when it comes to instances where no vibration is generated at the harmonic multiple or shaft speed.
Benefits of ODS Analysis
In any regular operating conditions of a piece of moving equipment, ODS analysis is useful in identifying the vibration pattern that occurs. Once a vibration is analyzed and measured, the equipment’s animated model is produced, and vibrating patterns are gathered from different directions and points of the mechanical system.
When performing ODS analysis, key items are used to gather and measure data. These tools include an ODS computer program or software package and an analyzer that have all necessary components for recording the equipment’s behavior while in motion. Its overall mechanical properties are also analyzed throughout the process.
Since ODS analysis gives professionals a visual idea about the structure’s exaggerated movement whether in the interior or exterior component, this helps in determining and addressing issues caused by forced vibration. So it is possible to have a more comprehensive concept of what is going on in and out of the machinery. Problems that exist in frames, associated bases, and rotating equipment are also identified easily. Most importantly, there is no need to take the machines off-line, which means productivity is not impacted.
With all these points in mind, ODS analysis offers a more practical, time-saving and in-depth means of pinpointing the problem, which result to quicker resolution without affecting business operations.