Optimization of Built-Up sections from basic elements like simple span beams or pined-pined columns.

[X4vier]

Hi, I want to know if anyone knows a tool or software to optimize weight and form of built-up sections?
Optimization of Built-Up sections from basic elements like simple span beams or pined-pined columns.
Something similar to the Auto-Select list from SAP2000, that choose between a list of commercial W-shapes with one is the highest that complies the design.
Thanks a lot.

 

[MotorCity]

I don't think you will find a program that optimizes built up shapes. I have not used SAP, but other programs like Risa and Staad have an option to design the member for you (presumably it selects the most efficient member). But that optimization is done from standard steel shapes. Using built up sections, there are an infinite number of configurations and member sizes.

 

[centondollar]

Optimization (as in mathematical optimization) only gives feasible answers in a reasonable time frame if the problem is well-posed. Linearity simplifies many things, as does a limited amount of variables. If the problem is non-linear, or if the constraints and problem setting are such that the problem has several local optimal values, then it is not always solvable.

In statically indeterminate frames, "optimizing" a single member, such as a stiff-stiff beam (flange thickness and/or web depth and thickness changing piecewise linearly according to the bending moment and shear), will create a new distribution of forces, after which you have to re-run the analysis and "optimize" again and again. This process might never terminate if the problem is sufficiently complicated.

Engineering principles is the tool for optimizing large, complex structures. Mathematical optimization may lead you astray (local minimum that is not global minimum etc.), and proving that the mathematical optimization gives you the optimal answer (a must if you wish to have confidence in the optimality of the solution) is an exercise in mathematics - not engineering.

 

[dold]

I think this might be possible in RISA3D by generating a bunch of built up sections and including those in a redesign list. I just sent tech support an email asking if there's a way to edit database files directly to batch-add custom shapes (presumably you'd generate the data for the new shapes in Excel or something and format it correctly) without having to do that manually in the shape selector. We shall see what they say.

To centondollar's point, in the workflow I just described you'd have to re-run the model each time you select the "suggested shape" until it converges. And yes, often times it will almost converge until it starts bouncing back and forth between two "nearly" optimal shapes.

 

[Celt83]

seems like your asking for topology optimization which would land you with one of the more general solids programs like solid works.

I'm making a thing:

http://www.thestructuraltoolbox.com

(It's no Kootware and it will probably break but it's alive!)