important Problem solving impact simulation for drone.

[varadude2]

Spoiler

The two components are to impacted to test the the strength of the landing gear and frame of the hexacopter.

I have followed the steps necessary for impact testing.

*And the contact between the impact surfaces is created. when opening the settings for the surface contact is gives error (out of memory).

Then the program shuts down reporting error.

*The simulation is carried out in drop test settings with impact plane being set below the slab model on which the drone has to be tested.

*Materials used are CRPF with Young's modulus:135 GPa, and density: 1.55e-06Kg/mm3. and for slab/base model concrete high strength. 

[John_Holtz]

Hi Varadude2. Welcome to the Sim Mech forum!

I see that you are getting results, so I am not clear what help you are asking for.

• If you are asking about the "out of memory" error that occurs when you try to open the contact settings, that is a known problem. (See this post.) The problem only occurs on Windows 10 that has been updated to the "anniversary" version. A fix for Sim Mech should be available soon.
• If you have questions about something else, please let us know.

[varadude2]

Thank you for the reply.

But the problem still pertains in the form that the simulation is/will be
running continuously for 20 hours before, error report in the details such
as [error(fatal), *time step reduction, as such], but the bigger problem is
that sometimes the simulation starts and in other cases it gives feedback
error such as Failed to Analyse the following.

[AstroJohnPE]

Hi Varadude2,

It is very difficult to know what is occurring in the simulation because your post is too general. It does not include any details that would allow someone to lookup the messages. (Have you searched the internet for any of messages that you are receiving?)

Can you provide more details? For example,

1. Where is the error or other message shown? (For example, in the design scenario name in the browser. In the solve log. In the file named X)
2. What is the complete text of the error or other message?
3. When does the error or message occur? (For example, before the analysis starts. When the analysis is X percent complete).

Also, it appears that you have modeled the "floor" using hundreds or thousands of elements. That has probably created thousands or millions of contact elements. That is not very efficient.

• Have you tried using the impact plane instead of meshing the floor and defining contact between the copter and the floor?
• If that didn't work, I suggest that you create 1 big element for the floor ("Mesh > Structured Mesh > 8 Point 3D") to replace the CAD part, and then define contact between the copter and the hand-built floor.

[varadude2]

thankyou again,

Sorry i was not clear on the problem,

* the problem is that i want drop test a multi component drone a step
format model on ground in simulation software, so i followed the usual drop
test method.

The testing was as usual in Nonlinear MES test.
1) Fixed the below base/ground in all direction and giving gravity
parameter to the drone in -Y.
2) I gave 0.5 second duration in parameters in the no. of steps section i
gave 100,
3) In load curve, i substituted the value and set 0 time multipliers to 1.
4) Then i created impact plane, in -Y direction slightly below the base.
5) then i created contacts, firstly i created sets between highlighted
surfaces , and then created surface contacts.
6) Then i set general contact settings to automatic.
7) Mesh as usual.
😎 after creating the contact sets i cannot edit them to change from press
to impact.
9) I simulated, the result is stuck in the event, and it is utilising 30%
ram, and is fully active but the results are not coming.

Please help.

[marwan_azzam · Accepted solution]

Hello varadudue2,

You say that you defined an impact plane but you also modeled the base (which is fixed) and defined contact between the model and the base.

As John mentioned, it should be one or the other.

You either use an impact plane and not model the base (ground).  No need to define contact, or

No impact plane.  Define contact between model and base.  Use a much coarser mesh for base, possible one big element to reduce the number of contact elements.

At this point, it sounds like the program is cutting down the time step size (you are at level 2 or above).  In the output table, this would be the column before the last and it's a number between 1 and 19.  If you are at a high level (say 8 or above) the analysis will take a very long time.

The reason you are not seeing any change in results is because by default, the results will not be saved for intermediate steps.  You will need to go to Analysis Parameters: Output and check the Output Results of All Timesteps box.  This will cause the software to save and display intermediate results (when the level is 2 and above).  Such change has to be done before launching the analysis.

I hope this clears things up for you.