Simple bending moment calculation

AI Thread Summary
The discussion focuses on calculating the maximum bending moment for a beam with specified loads and reactions. The original poster has attempted to determine the reactions at the supports but expresses uncertainty about their accuracy. Respondents suggest that the loading system needs clarification, recommending a sketch of the mechanical assembly for better analysis. They indicate that the calculated reactions may be incorrect and provide equations for determining the correct reactions and moments. The conversation emphasizes the importance of drawing shear and moment diagrams to facilitate accurate calculations.
Wilson123
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Hi,

Really need some help with figuring out the max bending moment in the diagram shown below (I'm aware this is extremely simple but time and stress appear to have the better of me, so any help is appreciated)

upload_2017-3-10_21-32-47.png


I think I've worked out the reactions at each support by doing m=wL as the following

0.785 x 0.08 = 0.63
0.785 x 0.28 = 0.22

I'm also aware that I could be completely wrong with what I've just put above.

SOS
 
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The beam would probably just tip over with the forces acting in the directions shown .

We need to understand the actual loading system more clearly before calculating bending moments .

Can you post a sketch showing the actual mechanical assembly that your line drawing represents ?
 
I don't think the reactions are correct. As drawn, ΣM = 0 = 0.2R + 0.785(0.08) : R = - 0.314 kN : The "-" sign simply implies you have the right reaction, R, acting the opposite direction. ΣF = 0 = - 0.785 - 0.314 + L : The left reaction, L = 1.099 kN : Given the reactions you should be able to calculate the moment.
Draw shear and moment diagrams.
 
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Vector1962 said:
I don't think the reactions are correct. As drawn, ΣM = 0 = 0.2R + 0.785(0.08) : R = - 0.314 kN : The "-" sign simply implies you have the right reaction, R, acting the opposite direction. ΣF = 0 = - 0.785 - 0.314 + L : The left reaction, L = 1.099 kN : Given the reactions you should be able to calculate the moment.
Draw shear and moment diagrams.

Thanks a lot for your help.
 
Draw a shear diagram first.
 
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