As its name suggests Operational Deflection Shape analysis shows the vibration pattern experienced during normal operational condition. This is different to other structural vibration tests such as impact hammer tests, bump tests or shaker tests which require a more controlled excitation force and are used to determine specific characteristics of the structure under test, such as natural or resonant frequencies.
The intention of this article is not to present any new scientific theories or ground breaking techniques, but to introduce new users to hammer impact testing and remind seasoned technicians of a method…
The 2013 Annual Prosig Prize for Engineering at Portsmouth University has been awarded to Peter Thompson for his project “Vibration Analysis of Aircraft Structures (Airframe)”. Peter completed his study at the…
In the previous two articles (What Is Resonance? (Part 1) & What Is Resonance (Part 2)) in this series we have looked at how we can identify a resonant frequency.…
James Wren (Prosig UK) explains how to store FRFs, coherence and/or time series data in modal hammer testing using Prosig's P8000 & DATS software. http://www.youtube.com/watch?v=JLumlmoRCvM
James Wren (Prosig UK) explains how nodes, components & structures are used in modal hammer testing using Prosig's P8000 & DATS software. http://www.youtube.com/watch?v=FmNCqv7p3pc
James Wren (Prosig UK) provides a step-by-step guide to performing a Hammer Impact Test on a structure using Prosig's DATS software and P8000 data acquisition hardware. http://www.youtube.com/watch?v=YrCM3H0_NpE
As mentioned in a previous post and in our last email newsletter (signup form on the right of this page) we are pleased to announce that the preview version of the new DATS Hammer Impact software is now available for download. (more…)
After listening to customer feedback, we have completely re-engineered the DATS Hammer Impact software. The new version will ship with the next DATS update (not the soon-to-be-released V7.0.23). In the meantime you will be able to download and preview the new package. You will of course need a P8000 system and a DATS licence with the Hammer Impact option enabled. (more…)
Prosig are delighted to have been invited to attend the 10th International Conference on Recent Advances in Structural Dynamics (RASD) to be held at The Institute of Sound and Vibration Research (ISVR) at Southampton University on 12th – 14th July 2010.
Prosig engineers will be on hand to demonstrate the P8000 range of 24-bit data acquisition systems and the DATS software including some of the specialist add-ons including Modal Analysis, Structural Animation and Hammer Impact Testing.
Prosig have a long relationship with the ISVR with many staff, both past and present, having worked or studied there and so Prosig are very pleased to have been invited to exhibit at the conference.
The following article will attempt to explain the basic theory of the frequency response function. This basic theory will then be used to calculate the frequency response function between two points on a structure using an accelerometer to measure the response and a force gauge hammer to measure the excitation.
Fundamentally a frequency response function is a mathematical representation of the relationship between the input and the output of a system.
We hear the word used a lot, but what is resonance? First, in order to explain we have to explain the terms we will use.
- A period is the amount of time it takes to complete one cycle
- The number of cycles in one second is the frequency of an oscillation.
- Frequency is measured in Hertz, named after the 19th-century German physicist Heinrich Rudolf Hertz
- One Hertz is equal to one cycle per second.
The following application note shows the steps taken to perform structural analysis using a hammer impact test on an automotive exhaust pipe structure to improve the structural damping properties of the exhaust pipe mount. This application note follows up to a previous article – “Preventing Component Failure In The Fast Lane”.
A recent signal processing application note described how the Prosig sponsored Dalmeny Racing Formula Ford Team, whilst contesting the UK Formula Ford 1600cc championship, suffered several minor structural failures on a particular part of an exhaust pipe mount. Prosig dispatched a team of engineers, and after a brief survey of the damage, the engineers made an outline assessment. They concluded that “the exhaust itself is resonating at particular engine speeds. This is causing some shear forces in the mount. This in turn is causing stresses in the material leading to cracking and eventually failure.”(more…)
[Updated 4th October 2021]
In this post, we will discuss the different types of transducers that can be used with the Prosig data acquisition systems and loggers. The post looks at the design and function of the different types of sensors and the applications they are normally associated with.(more…)