A circular tube has outside diameter D = 190 mm and inside diameter d = 166 mm. Find its second moment of area Ix about a diameter.
Centroid & second moment of area worksheet with answers
A 150 mm × 240 mm plate has a circular hole of diameter 40 mm whose centre is 45 mm from the left edge (at mid-height). Find the distance x̄ of the centroid from the left edge.
A symmetric I-section has flanges 140 mm wide and 20 mm thick, an overall depth of 400 mm and a web 14 mm thick. Find its elastic section modulus Sx for bending about the horizontal centroidal axis x.
A symmetric I-section has flanges 250 mm wide and 14 mm thick, an overall depth of 480 mm and a web 12 mm thick. Find its elastic section modulus Sx for bending about the horizontal centroidal axis x.
The T-section is used as a beam with the flange on top and carries a sagging bending moment of 30 kN·m. Find the size of the bending stress σtop at the top edge.
The T-section is used as a beam with the flange on top and carries a sagging bending moment of 40 kN·m. Find the size of the bending stress σtop at the top edge.
Answer key
- 1. Ix = 26.7 × 10⁶ mm⁴
- 2. x̄ = 76.09 mm
- 3. Sx = 1284 × 10³ mm³
- 4. Sx = 1969 × 10³ mm³
- 5. σtop = 26.41 MPa
- 6. σtop = 111.6 MPa
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