A beam of rectangular cross section 200 mm deep and 100 mm wide. If

the beam is 3m long, simply supported at either end and carries point

loads at 1m from the left end 5kN and 1m from the right end 10kN. Now I think I have worked out the maximum bending moment to be 8.4kNm at 2m from the left hand end correctly. I now need to find (a) the maximum stress in the beam (b) draw a sketch graph of the stress distribution through the thickness of the beam indicating which are tensile and compressive. I have drawn a rough sketch but don't know the values for it or how to achieve them. (c)

Determine the dimensions of the cross section which will minimise

the maximum stress value if:

• the cross sectional area of the beam can be increased by 20%

• the beam section is to remain a solid rectangle

• neither the breadth or depth of the beam section can be reduced

below their original dimensions.

Show the dimensions of the proposed beam cross section with the aid

of a sketch.

I have for this 240mmx120mm is that correct this would give a percentage reduction in stress value of 34.72%. Any help with this little lot I would be very grateful