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charger9198
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Illustration attached --> https://www.physicsforums.com/attachments/42037
I have a question which requires me to calculate the maximum stress in a simple supported beam.
The beam is 3 m long and rectangular and has two forces acting down vertically totalling 20 kN.
The breadth of the cross sectional plane is 100mm and depth is 200mm
I am a bit rusty on this but below shows my working;
- I Calculated the second moment of area about the neutral axis, = (b*d^3)/12
where b = 100mm and d = 20mm
(100*200^3)/12 mm4
thus (100*200^3)/12 *10^-12 m4
Moment area based on neutral axis = 6.666*10^-5 m4
y= 100 mm = 100*10^-3 m
I used the complete bend theory equation to transpose to ;
σ=M*y/I
σ= (30*100*10^-3)/(6.666*10^-5
= 2.25*10^6 Nm^-2
So maximum stress = 2.25 Mn
both edges are equal distances from the neutral axis
Can someone tell me if I am correct? or on the right lines?
I have a question which requires me to calculate the maximum stress in a simple supported beam.
The beam is 3 m long and rectangular and has two forces acting down vertically totalling 20 kN.
The breadth of the cross sectional plane is 100mm and depth is 200mm
I am a bit rusty on this but below shows my working;
- I Calculated the second moment of area about the neutral axis, = (b*d^3)/12
where b = 100mm and d = 20mm
(100*200^3)/12 mm4
thus (100*200^3)/12 *10^-12 m4
Moment area based on neutral axis = 6.666*10^-5 m4
y= 100 mm = 100*10^-3 m
I used the complete bend theory equation to transpose to ;
σ=M*y/I
σ= (30*100*10^-3)/(6.666*10^-5
= 2.25*10^6 Nm^-2
So maximum stress = 2.25 Mn
both edges are equal distances from the neutral axis
Can someone tell me if I am correct? or on the right lines?
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