January 12/14th, 2016 Seminar #2 Mec E 360

Problem 1: Find the principal stresses given

𝜎𝜎𝑥𝑥𝑥𝑥 = 50 MPa

𝜎𝜎𝑦𝑦𝑦𝑦 = 30 MPa,

𝜏𝜏𝑥𝑥𝑦𝑦 = 20 MPa

𝜎𝜎𝑧𝑧𝑧𝑧 = 10 MPa

January 12/14th, 2016 Seminar #2 Mec E 360

Problem 2: Determine the material index for a light, strong, simply supported beam with a point load at the centre with a fixed length 𝑙𝑙.

January 12/14th, 2016 Seminar #2 Mec E 360

Problem 3 Find the material index for a telescope mirror of diameter 2𝑅𝑅. The self-weight deflection of the centre cannot exceed the wavelength of light.