I've been asked to measure torsional vibration due to the torque pulse of a two cylinder engine on a tractor. The idea is to isolate the effect of torque pulse and determine the effectiveness of a torsional damper in reducing this effect. I'm visualizing the accelerometers 180 degrees apartand...
Tha shaker will be driven with a low amplitude sign sweep. Say 5 -400 Hz at 0.1 g, sweep rate of 0.2 Hz / sec. I will be looking at all frequencies in this range (resonant and non-resonant). At each of these frequencies the displacement will be given by the accelerometer and be used to calculate...
I purchased an IOTech strain book with the intent of measuring strain of components on a shaker table (3300 lbf single axis TIRA )and on lawn and garden applications during normal usage. This would be used to verify that the shaker was replicating the strain levels seen in the field. Once the...
Hello all,
Read through an archive thread (thread384-6080) on putting components on angled fixtures (oriented in the vector sum direction) to simulate three directional vibration on a single axis shaker.
Currently this is the preffered way of testing components where I work. The benefit is...
Hello,
I am currently comparing MSC.ADAMS pre and post processors. I sat in a presentation from Altair about using MotionView as a pre and post processor for ADAMS, instead of using what you get with the software, ADAMS VIEW.
Some Questions:
Does anyone have experience with both packages...
Hello All,
I was hoping to get some thoughts on simulating three directional vibration on a one-directional shaker. I am running small engines (3-30 Hp, one to three cylinder) and engine components (mufflers, air cleaners, carberateurs, etc.) on 3500 lbf TIRA shaker. Generally I test 4-20...
Hello All,
I have a tamper application that experiences very high amplitude, very low frequency vibration (e.g. 20g @ 0-3 Hz) when tamping a hard surface. Normally to reproduce field data on the shaker I exclude the 0-10 Hz vibration data and run 10-800 Hz, the range of structurally damaging...
Hello All,
Lately been thinking about accelerated testing. There was an article in TEST magazine by William Kipp who references two papers I am trying to track down:
1. "Focused Simulation" 1993, Dennis Young
2. "Selection and Performance of Vibration Tests", 1971, by...
Greg,
Thanks. I am also concerned with coupling opposite walls of a fuel tank with some type of spring element. I cross-posted this to the FEA group and some were recommending using spring elements from the walls to the fuel cg with a mass element at the cg. Then they reccomended tuning the...
Hello,
I am thinking of ways to run a FEA vibration analysis of a fuel tank full of fuel. Actually I want ot examine the bracket which supports the tank and I think the fuel in the tank will make a significant differnence.
My problem is how to simulate the mass of the fuel in a tank, but have...
Hello,
I am thinking of ways to run a FEA vibration analysis of a fuel tank full of fuel. Actually I want ot examine the bracket which supports the tank and I think the fuel in the tank will make a significant differnence.
My problem is how to simulate the mass of the fuel in a tank, but have...
Hello,
Does anyone have an electronic copy of ANSI spec B175.3-1997 they could send me?
Also, does anyone know the recommended limit of ANSI weighted hand values?
Some of the technicians I work with say the limit is 5.0 m/s^2 but I'd like to confirm that.
Thanks in advance,
George V.
Brad,
I think a modal based implicit dynamic analysis may be the ticket with this problem. I have ABAQUS/Standard available to me. I have done numerous mode based steady state dynamic problems so I am familiar with the pros and cons.
In theory I could output the nodal displacements from...
Greg,
I think I see where your going, a static modal with force input which represents the eccentirc loading (could be determined by a mix of fea and hand calcs.). But what I am trying to do is model this as a dynamic event (i.e. a time history) not as a modal (i.e. steady state dynamic). I may...
Hello All,
Any body have any ideas on how to analyse wobble of a mower with a bent blade and bent crankshaft USING FINITE ELEMENT ANALYSIS? I know how to do the test, and here is an example of were testing would be much easier than FEA. But say you had to do this in FEA, any ideas on the...
Greg,
How do you determine / test / define the below term you used? Could you give more detail?
"non linear frequency dependent characteristics for isolators"
George Vandyke
Hello All,
Has anyone done any work on incorporating the vibration mounts into Finite element analysis (ABAQUS or NASTRAN)?
the only way I could think of it, is to measure the spectral transmissibility of the mount by itself, then define a material damping of the mount material which is a...
Hello All,
I'm looking for a shaker table with a controller that can replicate field psd data.
I've come across Vibration Research for a good controller and TIRA for the shaker. Can anybody ercommend any other vendors.
Specs: Shaker 500 lbf, max moving weight about 60-70 lbf,
frequencies...
Mark,
yes I get all you said, most of it was in my original post. the question is which stress frequency do you use? If you have one dominant frequency, then you use that apply it to a S-N curve of use a fatigue method to *estimate* life, but what if you have multiple high stress frequecies ...
Greg,
I am familiar with rainflow analysis I dont think it can be used here. I am forced to work in the frequency domain. The test data is freqeuncy and the solvers ive used (NASTRAN and ABAQUS) perform moded based frequnecy response.
Granted, frequency stress values can be FFTed to time...
