Problem 1-54

The two members used in the construction of an aircraft fuselage are joined together using a 30°fish-mouth weld. Determine the average normal and average shear stress on the plane of each weld.Assume each inclined plane supports a horizontal force of 2 kN.

Given:

P 4.0kN:=

b 37.5mm:= hhalf 25m:=

θ 30deg:=

Solution:

Equations of Equilibrium:

+ ΣFx=0; V− 0.5P cos θ( )⋅+ 0=

V 0.5P cos θ( )⋅:= V 1.732 kN=

+ ΣFy=0; N 0.5P sin θ( )⋅− 0=

N 0.5P sin θ( )⋅:= N 1 kN=

Average Normal and Shear Stress:

Ahhalf( ) b⋅

sin θ( ):=

σNA

:= σ 533.33 Pa= Ans

τavgVA

:= τavg 923.76 Pa= Ans