Find the height ȳ of the centroid of the T-section above its bottom edge.
Centroid & second moment of area worksheet with answers
A rectangular section has width b = 200 mm and height h = 325 mm. Find its elastic section modulus Sx for bending about the horizontal centroidal axis x.
A hollow rectangular (box) section has outer width B = 240 mm, outer height H = 400 mm and a uniform wall thickness t = 10 mm. Find its radius of gyration r about the horizontal centroidal axis.
A 200 mm × 150 mm plate has a circular hole of diameter 50 mm on its vertical centre line, with its centre 90 mm above the bottom. Find the second moment of area Ix about the horizontal axis through the centroid.
The T-section is used as a beam with the flange on top and carries a sagging bending moment of 5 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 25 kN·m. Find the size of the bending stress σtop at the top edge.
Answer key
- 1. ȳ = 126.7 mm
- 2. Sx = 3521 × 10³ mm³
- 3. r = 148.7 mm
- 4. Ix = 55.47 × 10⁶ mm⁴
- 5. σtop = 7.068 MPa
- 6. σtop = 51.23 MPa
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