A threepoint bending test is performed on a glass specimen h

A three-point bending test is performed on a glass specimen having a rectangular cross section of height d = 5.3 mm (0.21 in.) and width b = 11 mm (0.43 in.); the distance between support points is 44 mm (1.73 in.). Compute the flexural strength if the load at fracture is 300 N (67 lb_f). sigma_fs = MPa

Solution

The formula for the flexural stress is

Stress = 3FL/2*b*d*d

Where

F – force applied

L – distance between support points

B – width

d- depth of beam

By substituting the values, we get

Stress = (3 * 300 * 0.044)/(2*0.011*0.0053*0.0053)

           

            = 64079743.68102528 N/m2

            = 64.08 MPa