Technical Notes

View Application Notes Based on Common Questions Received from Customers

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Creating a Fatigue Damage Spectrum Test - VN0019

Author: Jade Vande Kamp
Abstract: What is the process to create a test using the FDS software? This tech note addresses the neccesary steps to creating a good FDS Test. 

The Fatigue Damage Spectrum (FDS) software is easy to use, but there is a sequence of steps that must be followed in order to properly utilize this software. The goal is to start with a single or multiple time history file(s) that represent the vibration a product will experience through its life, then create a Random PSD that is the damage equivalent to one lifetime of that product based on the imported files.  ... Read Full Article


Specific Values for m and Q - VN0018

Author: Jade Vande Kamp
Abstract: How can I determine a specific m and Q value for a product for use in calculating the Fatigue Damage Spectrum (FDS)? This tech note will dive into the answer to this question and help you determine the specific and correct m and Q values to run your FDS test.

Vibration Research’s Fatigue Damage Spectrum (FDS) software is a tool which utilizes weighted time history files representative of the end-use environment of a product to create a FDS... Read Full Article


M and Q Values for FDS - VN0017

Author: Jade Vande Kamp
Abstract: How do the m and Q values effect the outcomes of FDS generation, and test compression? What values of m and Q can be used, as a starting point, for test development of a mixed composition component? This tech note addresses how to answer these questions by defining the m and Q values for the FDS test.

For the analysis of a time history file when generating the FDS, a low Q value spreads ‘damage’ out amongst neighboring frequencies, a high Q concentrates ‘damage .... Read Full Article


Fatigue Damage Spectrum FAQ'S - VN0016

Author: Jade Vande Kamp
Abstract: What are some common questions that arise today in regards to Fatigue Damage Spectrum Testing? Find out many of the questions and answers by reading this tech note.

The Fatigue Damage Spectrum (FDS) software is a tool designed to give engineers the ability to create a random test profile that is the damage equivalent to weighted time history files that portray the end use environment of a product. In addition to this real-world relationship, the FDS can be used to compare multiple failure runs of a product, compare specifications to real world data, and determine if current testing is valid or if a product is being under/over tested. .... Read Full Article


Averaging of Accelerometers - VN0015

Author: Aaron Offringa
Abstract: Using the VibrationVIEW software allows the user to use the average of multiple channels for control. In this technote, we will answer the question, "How does one use the average of multiple accelerometers for control?"

Averaging control is possible in our Sine, Random, and Shock software modules. First select your test and go to the ‘Channels’ tab.... Read Full Article


Random Lines of Resolution - VN0014

Authors: Aaron Offringa & Caleb Chamberlin
Abstract: VibrationVIEW software has the ability to adjust the lines of resolution for random vibration testing. This abstract illustrates how you can adjust the lines of resolution within the software and explains the benefits of doing so. A customer asked if we could help them eliminate the low frequency energy that was outside of their test parameters. This low frequency energy was close to the displacement limits of their shaker.

If you own the Random test module, choose ‘New Test’ in the VibrationVIEW Software. Then click the Random button as seen below...... Read Full Article


Sine on Sine Testing With Version 2014 - VN0012

Author: Aaron Offringa
Abstract: Using the Sine-on-Random test software, one can run a Sine-on-Sine test in VibrationVIEW version 2014. A customer asked if we could help him with setting up a Sine‐on‐Sine test to match a spec that he had. He was familiar with the Sine‐on‐ Random and Random‐on‐Random testing modes from Vibration Research, but was wondering what he needed to be able to do a Sine‐on‐Sine test.

To do this type of testing, the customer must have our Sine‐on‐Random Vibration Research test module. The first step is to click ‘New Test’ in the VibrationVIEW Software. Then click the Sine‐on‐Sine button as seen below. ... Read Full Article


Mirror Vibration Evaluation Procedure - VN0011

Author: Ryan Quellet
Abstract: The GMW14201 specification (Mirror Vibration Evaluation Procedure) is described. Many people have asked what the GMW14201 specification is and what is needed to perform a test that matches this specification.

The GMW14201 specification is a rotational vibration measurement test implemented on inside and outside automotive rear view mirrors. It is designed to measure the rotational response of a mirror when subjected to vertical input vibration. ... Read Full Article


Fatigue Damage Import - VN0010

Author: David VandeBunte
Abstract: Test engineers often ask how to create a random profile from recorded data.  Even after coming up with a profile, it may not be clear how long to run it or how to speed up time to failure.  This tech note addresses how to answer these questions using the concept of material fatigue and VibrationVIEW. I have 10 min. of road data and would like to make a random test that re‐creates the same spectrum from the field in my lab.  How can I run an equivalent of 600 min. of road data in 150 min. on my shaker?

Begin by finding the random import tab and choosing the fatigue damage technique.  To do this, create a new “Random” test, click “Advanced” at the bottom of the dialog, and navigate to the “Import” tab.  In the section “Import Method” on the dialog, choose “Fatigue Damage” to indicate you would like to (1) see a fatigue damage spectrum and (2) automatically adjust the time your test runs after the file is scanned (Figure 1).... Read Full Article


Computing Relative Displacement - VN0009

Author: Jon Drnek
Abstract: Two methods of calculating the relative displacement between two channels are described. We often get asked how to compute the relative displacement between two channels. There are two ways this can be accomplished that trade off accuracy and ease of use.

This is not just a simple matter of subtracting channel two from channel one. That only works for a pure sine tone if the channels are perfectly in phase. As an example, let’s say that channel 1 and channel 2 both are experiencing a sine tone with an amplitude of 1 inch. If the two channels are perfectly in phase, the relative displacement between the two will be zero. If they are 180 degrees out of phase, the relative displacement will be 2 inches.... Read Full Article


Create New Random Profiles from Response - VN0008

Author: Matt Millard
Abstract: This tech-note delves into the details on using a response channel to develop a new demand test profile for random. This function is useful in many applications and the one discussed below uses a combination of accelerometers and microphones for control and monitoring. The question has been raised in the past on ability to control a vibration test with something other than accelerometers. And, an even deeper question has come up on how to generate a new test profile (demand) based on the response of a monitor signal that may or may not be an accelerometer. The specific question being covered relates to the desire to do circuit board HALT/HASS type testing in an acoustically driven vibration test chamber. The key to this testing is to get the required vibration levels on the circuit board by means of controlling the sound.

The method described below uses an accelerometer on channel 1 as initial control and a microphone on channel 2 as response. The idea is to “capture” the spectrum of the response channel and make a new test profile and then control the test using the microphone.... Read Full Article


Remote I/O with Solid State Relays - VN0007

Author: Mark Chomiczewski
Abstract: A customer wanted to use the VR9500 remote I/O and VibrationVIEW to initialize a start-up sequence for their hydraulic power supply. They also wanted to have an input condition satisfied before user could begin to “Run” a test profile. In this tech note we will answer the following questions: 1. "How should the remote inputs and outputs be configured?" and 2. A customer was concerned the output did not have sufficient voltage to drive his SSR after checking contact side for continuity with ohm-meter."

Customer was using Grayhill SSR and needed output voltage to be 4-5VDC. We recommended:... Read Full Article


Accelerometer Calibration - VN0006

Author: Matt Millard
Abstract: The VR8500 and VR9500 Revolution vibration control systems can be used (with appropriate software options) to verify the calibration of an accelerometer (or other input). The software feature also provides the ability to write to TEDS (Transducer Electronic Data Sheet). We will show in this tech note how to easily check the input sensor sensitivity and verify/calibrate the sensor and update the TEDS info if applicable to the sensor.

Use this option to verify calibration on all your accelerometers.  It provides an easy interface to calculate accelerometer sensitivity. ... Read Full Article


Sine-on-Sine Testing v9 - VN0005

Author: Jordan Van Baren
Abstract: With the use of the Sine-on-Random VibrationVIEW software, a Sine-on-Sine test can be run in VibrationVIEW version 9. A customer asked me if we could help him with a new spec that came to him for testing. The spec included Sine‐on‐Sine testing and he was wondering if he had the capability to do this testing. He was familiar with the Sine‐on‐Random and the Random‐on‐Random testing modes from Vibration Research, but was wondering if he could run a new spec which needed Sine‐on‐Sine with no Random background noise.

To do this type of testing, the controller must be enabled to run a Sine‐on‐Random test. The first step is to click ‘New Test’ in the VibrationVIEW software. Then click on the option to run a Sine‐on‐Random Test....Read Full Article


Quick Tricks for Entering a Random Test - VN0004

Author: Andy Cogbill
Abstract: Using VibrationVIEW's calculation methods, one can automatically calculate the third unknown value in a given Random profile when two of the following values are known: G2/Hz for Frequency 1, Slope, G2/Hz for Frequency 2. A customer called in with the following random specification: “Line1: .052 G2/Hz from 80 to 5 00 Hz,
Line 2: ‐6db/octave from 20 to 80 Hz, Line 3: ‐6db/octave from 500‐2000 Hz, Line 4: Total: 7.4 G RMS”. The customer was not sure how to enter the test into VibrationVIEW.

A random test specification can come in many formats. Vibration Research has taken the best of the formats and combined them for easy test entry in VibrationVIEW..... Read Full Article


Load Transducer Database - VN0003

Author: Jon Drnek
Abstract: These instructions for loading the transducer database with data from an external system will help us answer the question: "How can I load the transducer database in VibrationVIEW with data from my existing transducer database?"

>VibrationVIEW uses SQLite (www.sqlite.org)  as the database engine behind the transducer database.  The details on how to use SQLite are beyond the scope of this document but the documentation on the SQLite website is quite good..... Read Full Article


Creating a Running Test Log - VN0002

Author: Jon Drnek
Abstract: How can you keep a running log of a test? The standard Tables option can be used in combination with the Test Notes window to create a running log of the test.

The Tables option is designed specifically for this situation.  Tables are defined on the Tables tab on the test setting dialog.  The tab for a sine test is shown below.... Read Full Article


Customizing Quick Reports - VN0001

Authors: Philip Van Baren and Matt Millard
Abstract: The standard Quick Report functionality can be modified to meet individual test profile needs to help with test report efficiency. A customer called with a cry for help, “I have a classical shock test in which I need to run 3+ and 3‐ pulses in each of 3 orthogonal axes on 20 test samples.  I need to generate a report for my customer that indicates the Run Name (description of axis and sample) and highlights it, accelerometer location for each of the 21 channels used,  test schedule details and accelerometer calibration details.  I have to have one graph with all channels shown.  Then I need each channel individually (except Ch2 and Ch3) along with all the mentioned test details.  I’m currently doing this one graph at a time and by editing a graph annotation to show the channel description and then using the standard Quick Report and selecting ‘Active Graph’, ‘Test Schedule’, and ‘Accelerometer Details’.  I then edit the .rtf document to remove the channels I don’t need and I highlight the Run Name at the top.  This is going to take me days!  How can I do this easier/faster?”

One of the nice features about the Quick Report feature (generated by clicking on the “Report” button at the top of the VibrationVIEW screen) is that once you select the information or add text to a field, it is retained with the test profile that created the data... Read Full Article


 

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