Noise and Vibration Monitoring - Siemens
Noise and vibration are both dynamic processes and have a close physical relationship. Vibrating systems make noise, and noise makes structural systems vibrate.
Both noise and vibration are adversely affecting people and if sufficiently intense, both noise and vibration can permanently hurt people. At the same time, also structural systems, if excited by excessive noise and vibration over sufficient periods of time, can fatigue and fail.
Since noise and vibration are both dynamic processes, similar measurement systems, signal processing methods and data analysis techniques can be used to study them. As well as similar analytical and numerical approaches such as the finite element and boundary element methods and the statistical energy analysis approach can be used for both to predict them.
Substantial progress has been made in recent years in all sectors in making quieter machinery, appliances, vehicles and aircraft. This is especially true for mass produced items for which development costs can be spread over a large production run and where sufficient expenditures on noise and vibration reduction can be justified. Considerable progress has also been made in the case of some very expensive first cost machines such as passenger aircraft, in which large sums have been spent successfully to make them quieter. In many such instances, most of the simple noise and vibration reduction measures have already been taken and further noise and vibration reduction involves much more advanced experimental and theoretical approaches.
Noise and Vibration - Siemens
Machines and equipment are used for a variety of purposes. The noise and vibration of appliances that we may have home for example is very often simply just annoying. However, the noise and vibration of machines in industry, can be intense enough to permanently hurt people. Although each machinery noise and vibration problem is rather different, a systematic approach and use of several well-known methods often produce sufficient reduction and allowable conditions.
Noise and vibration control should always be incorporated at the design stage wherever possible because there are more low-cost options and possibilities then to make completed machines or installations quieter. After machines are built or installations completed, noise and vibration control approaches can still be achieved through various modifications and add-on treatments, but these are frequently more difficult and expensive to implement.
Let’s take an example from automotive industry.
Noise Testing - Siemens
As cars are being transitioned from human-controlled and gas-powered to autonomous and electric, their engines are becoming smaller and quieter. The cars of yesterday came equipped with large, noisy engines that masked the noise and vibration coming from other components such as steering systems.
The movement to autonomous cars also means the driver no longer needs to focus on the road. With the driver’s mind free to pursue other activities while the car is in motion, various sounds will seem much louder and more noticeable than in the past.
Until recently, noise was an issue that automotive original equipment manufacturers (OEMs) and their suppliers did not need to think about. However, in order to stay competitive, automakers must prioritize noise, vibration and harshness (NVH) and integrate it into their designs much earlier than they have traditionally done.
Engineers have traditionally used steel test benches to analyze NVH in automotive components. However, once the component is moved from the bench to a car, the vibration often increases significantly. As a result, it is extremely difficult to predict noise and vibration levels alone.
Automotive Vehicle Performance NVH Acoustics - Siemens
Additionally, due to the relatively new nature of quiet cars, noise and vibration has historically been one of the last areas that automakers have analyzed. This means that NVH issues are often only addressed right before production, which is disruptive and expensive. “With limited in-house resources, it is difficult to do technology development on top of applied development,” says Hayuru Inoue, senior engineer in the CAE Technology Development Department at Hitachi Automotive Systems, Ltd.
The steering system engineering team at Hitachi Automotive Systems set out to find a better way to predict NVH and they’ve partnered with Simcenter™ Engineering to use component-based transfer path analysis (TPA) to predict the steering system’s NVH inside an actual vehicle rather than just analyzing the data on a testing bench. Siemens worked with Hitachi Automotive Systems to “split” the components apart to see how the steering system was behaving and how that affected overall NVH in the vehicle.
The Hitachi Automotive Systems team also had access to the component-based TPA tool inside of Simcenter Testlab™ software, which is part of Xcelerator™ portfolio, the comprehensive and inte-grated portfolio of software and services from Siemens Digital Industries Software. Although it is possible to perform TPA inside this tool, many teams struggle with measuring the data. The engineering team at Siemens was able to provide the expertise that Hitachi Automotive Systems needed to not only generate data, but measure and interpret it.
By partnering with Simcenter Engineering, Hitachi Automotive Systems gained access to the latest applications and methodologies, freeing up its time to focus on NVH prediction for each component.
Hitachi Automotive Systems
“By shifting the vehicle testing from our team to Siemens, we have been able to significantly reduce our product development costs. Product improvement guidelines have been created, and we will begin to apply them to new products as well.”
Inoue expects that by partnering with Siemens, tests that used to take three days can be reduced to just one. “We anticipate this initiative with Siemens will allow us to reduce the number of prototypes from at least four to just two. That would result in a 50 percent time reduction in prototyping, component testing and vehicle testing,” he states.
Simcenter Testlab covers the extensive testing requirements of noise and vibration engineers, offering seamlessly integrated tools for structural dynamics testing, rotating machinery testing, acoustic testing and sound quality engineering.
Siemens
A short guideline that will help you with noise and vibration problems:
Built-in productivity
With its unique workflow-based interface, Simcenter Testlab sets new standards for ease of use, productivity and data consistency. The software guides the user through the steps of the test campaign, suggesting optimal settings for measurement and analysis of noise and vibration. Seamless data sharing between different applications delivers tremendous efficiency gains. Embedded analysis during acquisition accelerates the testing process and guarantees optimal data quality.
Go right to the source of noise and vibration issues
Simcenter Testlab guides users directly to the source of the problem using comprehensive analysis capabilities. It enables testing teams to efficiently troubleshoot design problems and trace the root cause of a problem directly to the source. It supports easy what-if analyses to quickly evaluate possible fixes and solve the problem effectively, cost efficiently and quickly.
Adapt to the changing world of testing
By testing existing components and bench-marking competitive products, Simcenter Testlab is extensively used to frontload data into the simulation process. It also provides loading information and feedback to update virtual models. It is systematically used to provide test-derived models for component and subassemblies that are too complex to model virtually. Easy to integrate into Simcenter Amesim™ software, Simcenter Testlab software provides critical support for making virtual simulation efficient and realistic.
Meet specific needs through flexibility, performance and precision for lab and mobile testing
With a large variety of supported transducers and signal conditioning, Simcenter SCADAS systems are optimally tuned to meet specific needs for noise and vibration testing and can be seamlessly integrated with Simcenter Testlab for accelerated measurement setup and correctly formatted results.
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Sources:
Handbook of Noise and Vibration Control. Edited by Malcolm J. Crocker Copyright © 2007 John Wiley & Sons, Inc.
Siemens Digital Industries Software, Simcenter
