Timothy A. Philpot - Mechanics of materials _ an integrated learning system-John Wiley (2017)

Combined Stress at K
The combined stress at point K is the sum of a tensile axial stress and a compressive
bending stress:
P
P ⎡ 1
1 ⎤ P
σ K = − = P ⎢ −
⎥ =−
96 mm 4.73043 mm ⎣96 mm 4.73043 mm ⎦ 4.97560 mm
comb, 2 2 2 2 2
The negative sign indicates that the combined stress at K is a compressive normal stress. A
second possible value for P can be derived from the expression
P
4.97560 mm
2
2
≤ 108 MPa = 108 N/mm ∴ P ≤ 537 N (b)
The negative signs can be omitted here because we are interested only in the magnitude
of P.
Controlling Clamping Force
The allowable clamping force is the lesser of the two values obtained from Equations (a)
and (b). For this clamp, the maximum allowable clamping force is P = 537 N. Ans.
mecmovies
ExAmpLES
m8.20 A C-clamp is expected to exert a maximum total
clamping force of 400 N. The clamp cross section is 20 mm
wide and 10 mm thick. Determine the maximum tension and
compression stresses in the clamp.
m8.21 A precast concrete beam is supported by a corbel on
a concrete column. The reaction force at the end of the beam
is 1,200 kN. This reaction force acts on the corbel at a distance
of 240 mm from the column centerline. Determine the
stresses at the base of the column at points a and b.
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