Thank you for your sharing and comments. I would like to extend the discussion by changing the topic of this thread.
Background:
There was a random vibration testing and the DUT was over-tested with two times higher Grms than the test profile. Screws are broken.... There were some static tests...
@IRstuff, there are some screws are broken.
The Grms is too high than it is designed but the duration is shorter... I was thinking how to consider the time factor....
However, I think if the Grms reached to the peak and it breaks the screws then I can consider using that Grms level into...
Hi, I have two conducted two random vibration testing with the same profile but different duration.
In Random Vibration, since it is linear analysis, no time parameter is needed... I would like to calculate the vibration energy based on duration and Grms.
Is the vibration energy formula...
Hi, I would like to know if the duration is different for the same random vibration test profile, would the energy still the same?
For example, if the part break under the profile below for 60sec, would this failure occurs to be expected for the same profile for 20sec?
Are we able to capture...
Hello`
I am designing an assembly trolley and determining allowable deflection of the plate as shown in red arrow in the picture (for reference) below.
May I know if there is standard for the allowable deflection? I understand for some beams design, there are rule of L/360 for instance. What...
Hi SWComposites, I do not have the drawing. The picture is used for reference.
Did some Googling, this insert seems for partial potting. If it is used for thru hole, both flanges designed in round shape...
During modeling assembly, always assume subsystems as point mass with MOI if the subsystem is large...
But why don't we model the subsystem in a simplified model (shell models)?
When we want to check for coupling issue, we then better to use reduced model for subsystems to be integrated with...
Hi, I always concern about inter-rivet buckling if the spacing is too large...
What about insert in honeycomb panel if the spacing between insert is too large? Is there a general rule that we can use, or we just calculate the buckling based on the alu sheet?
Thank you so much to all of you.
According to the launcher's specification, we need to apply 1.25 times to limit load for qualification level.
Limit load is provided by launcher.
For Acceptance Level : 1.10 x Limit Load
For Qualification Level : 1.25 x Limit Load
I am not sure if I need...
Hi, I wonder if we need to multiply the limit load with all the factors at qualification test level.
Static load = Limit Load x Design Factor X Yield Design Factor X Qualification Test Factor?
If I am extracting the bolt forces from the FEM model, should I also consider fitting factor as well...
Sorry... my question does not clear enough.
Assuming I have a base plate as shown in the picture and I put it on the shaker to do vibration.
Some of our colleagues expect to see the vibration energy not very far from the input. The PSD input is 11 GRMS but I measure some locations (opposite to...
Hi, I would like to ask if I should expect to see the frequency response same as PSD input for random vibration when the subject is stiff enough >500Hz?
I create a plate and run a modal analysis to get 700Hz+++
Then I run a PSD profile as below...
I thought I would get the output same as...
Does the pitching affect fastener pull out strength?
There is no input of the plate width needed in the calculation... Does it mean pitch is only driven by Shear load?
I have seen not only Nord-Lock suggesting the clamp length is 3 times of the bolt diameter. If the joint I use is (D), does it mean I have to use 3x dia for part A thickness? It seems too thick as I have seen this joint, like the picture below, in our product with thinner part A...
