LESSON 31.

Example: At a point in a bracket the stresses on two mutually perpendicular planes are 45 MN/m2 (tensile) and 25 MN/m2 (tensile). The shear stress across these planes is 12 MN/m2. Find the magnitude and direction of the resultant stress on a plane making an angle of 450 with the plane of first stress. Find also the normal and tangential stresses on the planes. 

Solution:

Module 8 Lesson 31 Fig.1.1

  • Plot OL = 45 MN/m2 and OM = 25 MN/m2

  • Drop perpendicular LT and MS , each 12 MN/m2 as shown in figure.

  • Join ST to get N and draw the mohr's circle to pass through S and T.

  • Draw NP at 900 to NT.

  • Draw perpendicular to OQ.

  • σn  = OQ = 47 MN/m2 (tensile)

  •  τ = PQ = 10 MN/m2 (shear)

  • σr = 48.05 MN/m2

  • φ = 120

 

Last modified: Wednesday, 11 September 2013, 8:48 AM