Battery Pack Shock Analysis

Neeraj Kumar

An electric vehicle battery pack is subjected to half-sine shock of 50g acceleration in 11ms. Which analysis type should be selected for such case in OptiStruct?

Thanks.

Adriano A. Koga

You can run a transient analysis in OptiStruct, and impose the half sine shock profile using the TLOAD2 card, by adjusting the half-sine durationfrequency.

11ms half-sine is equivalent to a 22ms period full-sine, thus 1/0.022 Hz.

 

Take a look at TLOAD2 card documentation in OptiStruct.

As a simplified version, you could calculate first what are your models critical frequencies, and knowing the predominant frequencies for each direction (using effective mass participation), you could calculate an equivalent static load, based on a Shock Response Spectrum (SRS).

Once you have the SRS for your 50g, 11ms half-sine, you will get an amplification factor (Acc_output/Acc_input) and you could apply it as a scale factor for your 50G's, and run a linear static case with this amplified acceleration. This would be cheaper than running a full transient analysis, but of course, with some assumptions.

https://community.altair.com/community?id=community_question&sys_id=2976843a1b2bd0908017dc61ec4bcb5c&view_source=searchResult

 

Example of a half-sine SRS.

Neeraj Kumar

Adriano A. Koga_21884 said:

You can run a transient analysis in OptiStruct, and impose the half sine shock profile using the TLOAD2 card, by adjusting the half-sine durationfrequency.

11ms half-sine is equivalent to a 22ms period full-sine, thus 1/0.022 Hz.

 

Take a look at TLOAD2 card documentation in OptiStruct.

As a simplified version, you could calculate first what are your models critical frequencies, and knowing the predominant frequencies for each direction (using effective mass participation), you could calculate an equivalent static load, based on a Shock Response Spectrum (SRS).

Once you have the SRS for your 50g, 11ms half-sine, you will get an amplification factor (Acc_output/Acc_input) and you could apply it as a scale factor for your 50G's, and run a linear static case with this amplified acceleration. This would be cheaper than running a full transient analysis, but of course, with some assumptions.

https://community.altair.com/community?id=community_question&sys_id=2976843a1b2bd0908017dc61ec4bcb5c&view_source=searchResult

 

Example of a half-sine SRS.

If, instead of transient response analysis, Explicit analysis is selected to perform the analysis. How will it affect the analysis, in terms of accuracy and different insights obtained form the results.

Thanks.