Learning Forum

[info]

Hi,

Is there a possibility to import e.g. time-history record (see a sample 10s earthqake record) as excitation (velocity, displacement, acceleration) into structural analysis in a convenient way such as copy/paste from Excel, or import from CSV?

My goal is to run a THA (time-history analysis) based on some external data.

Regards,

Csaba

[Gaurav Sharma]

Hi steelxpert

I dont think it is possible to either import or copy paste the inputs from excel. I understand that for the kind of loading you have shared, it is tedious to manually enter the Time vs Accelaration data in the load table.

But, it is important to note that Transient analysis is much more computationally expensive then static structural and the solution time is significantly high.  Generally it is not a good practice to perform a full fledged transient analysis corresponding to such complex data and transient analysis is a good fit only for simpler time dependent loading. And for simpler loading, manually defining the load table is no big deal either.

Typically such a requirement (excitations coming from earthquake) need a base excitation solution (Response Spectrum), where the time dependent load is converted into frequency dependent one, which is further solved by the program with relative ease. Unfortunately, Response spectrum is not exposed in Discovery AIM but is available with ANSYS flagships. 

In case you still want to give a try to the transient structural capability of AIM, you may also have to apply acceleration BC that would affect the entire structure, which again might be an approximation as the earthquake excitation is generally applied only on the mounting faces of the structure and not the entire structure.

With this information, please let me know if I can help you further.

Thanks & Regards,

Gaurav

[info]

Hi Gaurav_ANSYS

Thank you for the explanation - I am a practicing structural engineer, so I am well aware of the facts you kindly shared to me. I also have considerable experience with the dynamic capabilities of the ANSYS Mechanical products.

Response Spectrum analysis results can be misleading in some cases, where it is inevitable to maintain a THA. Sometimes we actually generate artificial seismograms based on the response spectrum defined e.g. in Eurocode.

Time-History Analysis is also very useful if there is plasticity in any of the structural members (beams).

Can you please comment/verify that providing such a simple (from user perspective) functionality (i.e. copy/paste-ing an excitation record from tabulated source) within AIM is not in the intention of the developers?

Can you also mention usage examples of use for this existing 'time-dependent' functionality of AIM?

Thanks,

Csaba

[Gaurav Sharma]

steelxpert 

I understand your intent and requirement of THA. I agree that importing CSV can be a useful functionality and would request you to please post this as a suggestion in ideas section.

However, as the Transient structural capability itself is a beta option as of now, I am not sure if this will get the due weightage. Coming to usage examples, again since this is a beta feature with very limited exposure, its difficult to comment upon it.

Thanks for your understanding.

Best Regards,

Gaurav