Patran Inertial Loading (Spatially Variant Accelerations)

[wvan794]

Hi all, I am using Patran 2013 with MSC NASTRAN 2013.1.1 as my analysis code (performing a linear static analysis) and am having the following issue:

I need to apply inertial loads that are spatially variant. In my first attempt to do so, I generated a spatial field and selected the field the Trans Accel <A1 A2 A3> input. Attempting to run the analysis, I receive the error message: The inertial load set "TestLoad" cannot be translated, because it varies spatially. The analysis code does not support spatially varying inertial loads. It is seems from this that the Trans Accel <A1 A2 A3> input in Patran under inertial load corresponds to a GRAV entry in NASTRAN. Reviewing the NASTRAN linear static user's guide, I note the entries ACCEL and ACCEL1. Either of these seem to be adequate for applying loads to my model; however, I haven't been able to find a way to include either as part of my load case in Patran. Does anyone have any experience with this?

 

[bisav]

I am not sure about this problem. But I feel that the problem could be due to the following reason. Inertial loads applies to the total system. So I doubt you can give spatially varying loads for inertial loads. Do you want a load which vary spatially or which vary according to 'time' ?



Stress Engineer
bibinncb@gmail.com

 

[wvan794]

Thanks for the response, I have actually resolved my issue at this point. I was seeking spatial variance and yes, you are correct that the inertial loads in Patran apply to the whole system. After diving further in the Patran interface to Nastran manual, it was evident that the ACCEL entry in Nastran has never been incorporated into Patran. As such, the simplest solution for me was to amend the *.bdf generated by Patran with an ACCEL entry. Not unlike the inertial loads incorporated in Patran, ACCEL still applies to the whole system; however, the magnitude of the acceleration varies with position in one direction. This was just what I needed, but if someone needed an inertial load that varies in two or three dimensions, this likely wouldn't work.