Creo Parametric Community Challenge 3 - Simulate a Drop Test

[DaveMartin]

This month’s challenge has a simulation theme. Many products have requirements regarding the ability to survive multiple drops from a given height. Your challenge is to simulate a drop test in Creo Parametric. Many people have a technique for simulating drops; if you don’t, how would you create one? You can use Creo Ansys Simulation, Creo Simulation Live, Creo Simulate, Mechanism Design Extension (MDX), Mechanism Dynamics Option (MDO), or any other module you see fit.

You may use any model of your choice; a simple block will suffice if that’s all you have. You can drop your object from any height that you choose, although heights of 4 to 8 feet (approximately 1.25 to 2.5 meters) are common. You can choose any orientation for your object; please do not feel like you have to follow guidance of sources like MIL-STD-810 with multiple orientations and multiple simulated drops. You can choose whatever results that you want to convey, such as stress contour plots, displacement plots, or motion animations. Bonus points for a screen recording or MDO / DAO (Design Animation Option) movie. The important thing is that we would like you to share with the community how you would simulate a drop test in Creo.

Find the PTC Creo Community Challenge Guidelines here!

[hadardor]

Hello, Thanks for this topic.

Find in attachment how I approached it.

[DaveMartin · Accepted solution]

I'm going to start commenting and posting about solutions to drop testing. Upon reflection, it is harder and more complicated than it sounds. I found a few articles in the PTC Knowledge Base that may help inspire people to work out their own solutions.

This one is a bit outdated, but there's some good information:

https://support.ptc.com/cs/cs_22/howto/mst2742/mst2742.htm 

[DaveMartin]

A second article from the PTC Knowledge Base. (By the way, if you are not using this resource regularly, you need to start.) Also a bit old (Mechanica era), it discusses techniques for using aspects of MDX and Creo Simulate for modeling impacts. It uses a pool table as an example.

https://support.ptc.com/cs/cs_22/howto/mmo839/mmo839.htm

[DaveMartin]

Here is a phone drop simulation created about 15 years ago by my former colleague Roberto Sanchez from NxRev. I will write about it in the blog post. It was made in MDO and involves cams, dampers, position motors, and a dynamic analysis.

This challenge is open to resellers and PTC employees. If anyone wants to show their prowess and represent their organization, they have until Friday.

[DaveMartin]

I will write about my experiences with drop tests in the summary blog post. I was going to replicate a simulation I developed in the 1990s for a shipping container for a surface-to-air missile. But then I realized I was lacking the necessary Creo Simulate license. (I suspect licensing may explain why there were so few submissions this month.)

As this was decades ago and computers weren't that good, I had to use a technique I wasn't crazy about, but it was the best we could manage back then. We would choose an orientation for the drop, and then use a three-point constraint on the end opposite where it would hit the ground. You have to have constraints in a static analysis; otherwise, it won't run.

Then we would apply a force corresponding to several G's of acceleration where it would hit the ground. Since we were using NASTRAN at the time, we would use what corresponds to a Dynamic Shock analysis where that force would be applied over a very short duration. (This, by the way, was before PTC acquired RASNA, which would become Mechanica, which would later become Creo Simulate.)

Maybe at some point I'll get the advanced license of Creo Simulate in order to demonstrate this technique.

Today, by the way, is the last day of the challenge.