A rectangular section has width b = 60 mm and height h = 325 mm. Find its elastic section modulus Sx for bending about the horizontal centroidal axis x.
Centroid & second moment of area worksheet with answers
Find the height ȳ of the centroid of the T-section above its bottom edge.
Find the second moment of area Ix of the T-section about the horizontal axis x through its centroid.
A symmetric I-section has flanges 220 mm wide and 12 mm thick, an overall depth of 340 mm and a web 10 mm thick. Find its second moment of area Ix about the horizontal centroidal axis x.
A 100 mm × 240 mm plate has a rectangular cut-out 40 mm wide and 50 mm high, centred on the vertical centre line with its centre 96 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 20 kN·m. Find the size of the bending stress σtop at the top edge.
Answer key
- 1. Sx = 1056 × 10³ mm³
- 2. ȳ = 160.4 mm
- 3. Ix = 22.04 × 10⁶ mm⁴
- 4. Ix = 168.4 × 10⁶ mm⁴
- 5. Ix = 113.5 × 10⁶ mm⁴
- 6. σtop = 40.7 MPa
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