problem.1) A three-point bending test was performed on an aluminium oxide specimen which is having a circular cross section of radius 3.5 mm; the specimen fractured at a load of 950 N when the distance between the support points was 50 mm. Another test is to be performed on a specimen of this similar material, but one that has a square cross section of 12 mm length on each edge. At what load will you expect this specimen to fracture if the support point separation is 40 mm?
problem. 2) A relatively large sheet of steel is to be exposed to cyclic tensile stresses of magnitudes 200 MPa and 50 MPa, respectively. Prior to testing, it has been determined that the length of the largest surface crack is 2.5 mm. find out the fatigue life of this sheet if its plane strain fracture toughness is 30 MPa(m0.5) and the values of m and A are 3.0 and 10-12, respectively, for Δσin MPaand a in m. Assume that the parameter Y is independent of crack length and has a value of 1.0.