Impact Analysis / Drop Test Simulation

[CSA]

Hello everybody,

I am trying to simulate a drop test of a headform & helmet in ProMechanica. I have actual acceleration and time readings from the accelerometers and material properties required for modeling the components however I wanted to know how should I proceed in simulating this concept. Should I create a mechanism by putting the servo motors to the headform and dropping them with the acceleration values that I have? Or is there any other method to do it? Please direct me to a link if any explaining the simulatio procedure for the same.

What I want to achieve through this simulation is the stress concentration in different parts of the head form.

So please let me know if anybody knows a procedure to do so.

Thanks in advance,

CSA

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[danderson]

CSA,

If you have current maintance you might try the link below. It's an old techniqe document related to impact simulation setup prior to wildfire. Process is the same just the commands are located in different places.
Wish PTC would update this one.

http://www.ptc.com/cs/cs_21/howto/mst2742/mst2742.htm

Hope this helps,
Don Anderson

[CSA]

Hello Don,

Thank you for responding, however when I click on this link it says I am not authorized to access it.

What other option can be devised to access it?

Please let me know.

Chandrika

[danderson]

Chandrrika,

You will need to be logged into your PTC account and have active maintance in order to access it.

Don

[BenCohen]

I'm trying to do a similar simulation, the tutorial mentions a 6DOF joint, is that the same as a 6DOF rigid link? I'm getting an underconstrained error in my model.

Thanks,

-Ben

[danderson]

Ben,

The 6DOF joint needs to be defined in a mechanism analysis. The tutorial above is a 2 part process.

First you run a mechanism analysis to get the values and contact areas then you use those parameters to definde a Mechanica Simulate Analysis.

Hope this Helps,
Don

[ehaenen]

If acceleration spectrum is known, I would propose a dynamic shock analysis. You would have to create a valid modal analysis model, use it to calculate (a large number of ) normal modes and subject to a shock response analyseis. this is however quite advanced. You might want to read up on the subject in:

DYNAMICS OF STRUCTURES,RayW. Clough, Joseph Penzien, THIRD EDITION.Chapter 5.