Explain in brief the terms: stress concentration and notch sensitivity, and their significance in design of machine element. A round straight bar with a diameter of d, = 20 mm is being compared with a bar of the same diameter, which has an enlarged portion with a diameter of d, = 25 mm. The radius of the fillets is 2.5 mm and the associated stress concentration factor is 1.74. Does enlarging the bar in this manner make it stronger? Justify the answer by determining the maximum permissible load P, for the straight bar and the maximum permissible load P2 for the enlarged bar if an allowable tensile stress of the material is 80 MPa. P, d, P, P, + 'p