Lecture # 23 & 24 Compound Stress Objective:- To find total stress ( and ) from central forces and moment. Compound normal stress: Normal stress caused by different faces and moments such as (N, My, Mz) Compound shear stress: Shear stresses caused by different forces and moments such as (Vy, Vz, T) y x z N My Mz Vy Vz T Compound normal stress Compound shear stress

Compound Stress y My N Mz My Vy Vz T Vy N = Mz Vz x z T Select + sign wherever moment is causing tension in +ve y or +ve z- axis.

Example: A force of 15000 N is applied to the edge of the member. Neglect the weight of the member and determine the state of stress at point B and C.

Solution:

Example: The member has a rectangular cross section. Determine the state of stress that the loading produces at point C.

Solution: N = 16.45 kN V = 21.93 kN M = 32.89 kN·m

Solution (cont.):

Example: The solid rod has a radius of 0.75 cm. If it is subjected to the loading shown, determine the state of stress at point A.

Solution: =

Solution (cont.): Internal Loading. = (c) 7000 N·cm 8000 N·cm 500 N

Solution (cont.): Normal Force. Shear Force.

Example: Normal Force. Bending moment. The rectangular block of negligible weight is subjected to a vertical force of 40 kN, which is applied to its corner. Determine the normal-stress distribution acting on a section through ABCD. Normal Force. Bending moment.

Solution:

Solution (cont.):

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