Hi,
I am trying to understand what is physical interpretation of inertia drive effect versus inertia coast effect in driveline theory.
Why are these effects = angular accelerations different in multishaft drivelines?
Success in one part. Thanks for replies. I get good results integrating in time domain, however, there is some (slight) phase change. In the test case this is not critical.
In the real problem this needs to be fixed, so frequency domain integration may be the key like MikeyP said. I am having...
SomptingGuy - in the real problem use of proximity sensor is not possible. We have sensors but they are not practical for this problem.
MikeyP - Yes, signal is exactly as you describe. Thanks a lot.
Thanks for replies.
FeX32 - Yes, sampling frequency checks. What would you recommend as better approach?
BobM3 - Acceleration is decaying sine wave. Yes, velocity is sine wave as well. Also, velocity is at zero at max. acceleration points...as it should be. Amplitude is way off. Integrating...
Hi,
We are going to measure accelerations from piece of machinery. Goal really is displacement by double integration.
Before attempting this, I have done some preliminary work with simple cantilever beam. In short, I glued a strain gage to fixed end and mounted single axis accelerometer to the...
Kinematics and Dynamics of Machines by Martin.
This is derived from energy method what Greg was referring.
w=sqrt((g*sum(My))/sum(My^2))
M - mass of disk i
y - distance from horizontal to deflected shape location of disk i
We recently designed similar systen using loadcells. We use beam type loadcells that respond only to vertical load. We compensate offset angle from two axis via inclinometer. This compensated angle is mg*sin b, where b is the offset angle. If your system is stationary, this works fairly well...
Here is one example that I have come across myself. Few days after my graduation I happened to be in the area of potential employer. I got the phone call and after brief discussion was asked to come for an interview right away!!
I was dressed in regular clothing and actually mentioned this on...
All,
Thanks for helpful comments. I am getting reasonable results now, however, I have not verified it by displacement transducer yet.
Thanks again.
suviuuno
Thanks for helpful information SomptingGuy and Greg. I will set up a small experiment, where I will measure displacement as well just to see the difference.
I filtered signal and got what might be in the right area. Quite hard to say, I think. I'll keep you posted.
Hi,
We are testing effect of accumulator in rock drill concept. We have mounted two tri-accelerometers in hydraulic hoses that feed the drill to capture the difference in acceleration/frequency, if any.
To my surprise, results were fairly same.
Now, I would be interested in position...
BobM3,
I partly disagree with you. Your method will work if strain gages are way off from stress concentrations when measuring nominal loads.
If we are after hot-spot stresses, gauges are located close to weld toes as in most cases in our industry. It would be impractical to build FBD due to...
Consider boom with stain gauges glued at the support of the boom.You know the weight of the boom and all the accessories. Let's say you do zero balance when boom is horizontal pointing straight ahead. Now you move the boom into known positions and as a result you get known strains. I feel it...
Hi,
To get velocity from acceleration data we integrate once. Integrating velocity we get displacement.
Acceleration data is in time domain.
Velocity is given by integrating acceleration in time domain and same for displacement or integrating acceleration in frequency domain to get velocity...
Quote by Greg: "Adding constraints does increase the frequencies of the system."
Are you sure this is always the case? I agree, generally this is the case, but I surprised myself with this "odd ball" a year ago. Cantilever case is different from beam supported at both ends -> therefore not...
Hi,
I have been puzzled by this same problem before.
I would say free/free has higher frequency than clamped. Looking at mode shapes will reveal the answer. This goes against common sense as, in general, adding constraints increases natural frequency.
In clamped case first bending mode shape...
Hello
I am modeling symmetric load carrying welded cruciform joint under four point bending. Why does extreme tensile fiber stress dips below nominal fiber stress(far away from weld) at about thickness away from the weld toe before peaking due to discuntinuity of weld? Tensile case is clear...
There is small change in mass, and like Greg indirectly pointed out longitudinal stress is half of hoop stress.
My guess is that longitudinal stress does matter and well overrides increased mass due to oil. As a result nf increases, I am going to say it almost doubles.
