Principle Calculation of Stresses at Sections - Crane Frame for Vehicle mounted cranes.

[JarlSim]

Hi.

I am trying to define a set of calcuations to determine if a specific cross section of a frame structure is strong enought to withstand forces applied to the cross section.
I have reviewed standards and regulations for clues towards defining the calculations needed for the above stated problem, but have thus far been unsuccessful.

My question in brief;
Based on force applied to a frame structure due to load lifted by a loader crane mounted rigidly, how can i determine the stresses in diffeent cross sections of the frame structure?
My need is to optimize the cross sections for several sections along the length of frame to reduce weight but still acheive a safetyfactor of at least 1.2 from yield strength.

I have attached a simplified sketch to illustrate my question.

I would appreciate any input to help me solve this problem.

 

[GregLocock]

I'd check that safety factor if I were you.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

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[GregLocock]

First draw a free body diagram to get equilibrium

Then draw your shear force diagram along the beam

then draw the bending moment diagram.

Then you know that M/I=s/y
where s is the stress at a height y above or below the neutral axis at that point.

In your case you've got two forces at the base of the crane so you could apply each individually and use superposition.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

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[rb1957]

how is the crane boom connected to the lower beam ?
what loads is the crane boom applying to the lower beam ?
as greg says, draw a FBD of the crane boom, then a FBD of the lower beam.
this'll show you that the RH reaction is larger than your applied load

If I understand your stress sketch (stress1 to stress4) ... I don't think the stress (whatever stress you're talking about) is heading to zero.

another day in paradise, or is paradise one day closer ?