Calculating J values for non-standard sections
Calculating J values for non-standard sections
(OP)
I have some non-standard sections that I am trying to use in a model however I need to work out the torsional properties of the members and am having trouble finding an accurate way of calculating them either by hand or by computational methods (without trying to get my director to shell out on proper shape-modelling software).
I was wondering if anyone here had done anything like this before or had come across some way of being able to analyse these things?
To give you an idea of what I'm looking at, I have for example an I-section with 12mm plates welded top and bottom and 10mm plates welded to the sides of the section and then a triangular section welded to one side of the member. I believe that it will be sensible to ignore the triangular section as it's only really there to make the connection to another member easier, however I can't use simple theories to work out the torsional properties since the section isn't 'thin walled', and assuming it was would be incorrect.
Any help would be greatly appreciated. You guys have been very good to me so far and I look forward, when I've got your experience, to be able to impart my help on others on this forum!
I was wondering if anyone here had done anything like this before or had come across some way of being able to analyse these things?
To give you an idea of what I'm looking at, I have for example an I-section with 12mm plates welded top and bottom and 10mm plates welded to the sides of the section and then a triangular section welded to one side of the member. I believe that it will be sensible to ignore the triangular section as it's only really there to make the connection to another member easier, however I can't use simple theories to work out the torsional properties since the section isn't 'thin walled', and assuming it was would be incorrect.
Any help would be greatly appreciated. You guys have been very good to me so far and I look forward, when I've got your experience, to be able to impart my help on others on this forum!






RE: Calculating J values for non-standard sections
The wraping constant Cw for I shapes is approx. [d^2(Iy)]/4
I hope this helps
RE: Calculating J values for non-standard sections
RE: Calculating J values for non-standard sections
RE: Calculating J values for non-standard sections
ash060's method is likely to give a low estimate if I understand it correctly (eg consider the result of 4 small vs 1 large square section).
Cheers
Greg Locock
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RE: Calculating J values for non-standard sections
RE: Calculating J values for non-standard sections