Designing solar panel structure

[enggirl2014]

Hi,

I am a co-op student currently working on designing a structure for a solar array. I am having difficultly calculating the total load the the mounting beams would have to support. I know the snow and wind load and the weight of the panels. I think it may have to do with tributary areas, possibly, but all the cases I see online are only floors not anything slanted with loads that distributed vertically and horizontally and point loads. Any direction or references would help, I'm mechanical so loads distributed over areas are quite new to me and can't seem to grasp it no matter how much research I do. I've attached a image of my model.

 

[canwesteng]

Treat your solar panels as simply supported beams on simple supports and solve with statics.

 

[msquared48]

Half of the panel weight (dead and snow) are transmitted to each of the beams as a line load, or a uniformly distributed "uniform load". That's why they call it a "uniform load". It's just a uniform load on a simple beam.

Take the reactions from the beams to the vertical mount assembly and design for any overturning and eccentric loading through statics. Should not be that complicated.

Mike McCann, PE, SE (WA)

 

[Lomarandil]

For what it's worth, "Tributary Areas" are a way to simplify indeterminate or geometrically complex structures based on the principle that load always want to go to the stiffest element available to resist it. To be accurate, it requires that your first load distributing element (whether a floor or in this case a solar panel) is relatively flexible compared to what's beneath (girders, columns, or your frame). Even if it doesn't strictly apply though, it can be a good back of the envelope check to make sure your results are reasonable.

Thankfully, as the others have pointed out, your system isn't indeterminate or geometrically complex. You just need to draw up a bunch of free body diagrams to work the statics out. First draw one with the loads, your solar panel as the structural element, and the frame below as your supports. The reactions you calculate at theses supports then become the loads for your next FBD of the frame.

 

[enggirl2014]

Hi,

Thank you all for you advice. I've gone ahead and done the calculations, just with variables, but when I substitute the equations my reaction variables cancel each other out. Did I make a wrong assumption maybe?

Thank you

 

[enggirl2014]

2nd view.

 

[enggirl2014]

3rd view.