Learning Forum

[KRISHNAPRASAD T S]

Hi, I have a doubt regarding why the equivalent stress reduced as I did a drop test for a cycle frame of cfrp material in explicit dynamics and the drop height was 0.5m for which it showed around 350Mpa but as I did the same for 1.5m drop height it's showing 13Mpa.

I used ansys drop test wizard for setting up end time and cycles. 

Please reply ????. 

[Armin]

Hi Krishna,

Could you include a screenshot of the two models showing eq. stress at the time you observe this discrepancy in the results?

[KRISHNAPRASAD T S]

the above figure is the stress for 1.5m drop height.It's showing 13Mpa as max stress. 

And this is the results I obtained for 0.5m drop test.

 

all the analysis settings are automatically made by ansys drop test wizard.

Please correct me if I'm doing it wrong, I just started learning ansys and don't know much about how to set end time and cycles.

Please help me.

[Armin]

Thanks Krishna.
I believe what we are seeing in the pictures is essentially stress waves travelling through the frame. Recall that this is a dynamic situation.

I would suggest that you select a point of interest in the model, like a specific location in the frame at or near the impact location, and then plot the eq.stress versus time for an element located in the area of interest. Then compare the results for both drop heights, and hopefully that provides a clearer picture of the results.