Calculation based on real weld sizes
1) The area of the welds
(based on throat weld thickness at 0,707.5 = 3,5mm)
Area = (57.3,5 + 2.55.3,5) = 584,5mm2
2) The moment of area about x-x =
M of Area = (57.3,5.3,5/2 + 2.55.3,5.(27.5 + 3,5)) = 12 284mm3
3) The centroid v = Moment of Area/Area
M of Area / Area = 21 mm
4) The radii rA, rB, rC & rD are calculated ..
rA = rB = Sqrt ((58,5-21)^2 + 28,5^2 ) = 47,1
rC = rD = Sqrt ((21)^2 + 28,5^2 ) = 35,40...
5) The angles θA, θB, θC & θD are calculated ..
θA = θB = tan-1 ((58,5-21)/ 28,5 ) = 52,7o
θC = θD = tan-1 ((21)/28,5 ) = 36,4o...
6) The direct shear stress on the area = Force /Area
τ S = 5000/584 = 8,56 N/mm2
7) The Moment on the weld group = Force.Distance to centroid
M = 5000.(100+21) = 6,05.105Nmm
8) The polar moment of inertia of the weld group = J = Ixx + Iyy
Iyy = 2.[55.3,53 /12 + 3,5.55.(50/2 + 3,5/2)2]
+ 573.3,5/12 = 3,3.105mm4
Ixx = 2.[553.3,5/12 + 3,5.55.(55/2 + 3,5 - 21)2]
+ 3,5357 / 12 + 3,5.57.(21-3,5/2)2 = 2,097 .105mm4
J = Ixx +Iyy= 5,4.105mm4
9) The stress due to torsion
τ TA = τ TB = M.rA/J.. and ..τ TC = τ TD = M.rC/J
τ TA = 6.055Nmm.47,1mm / 5,4.105mm4=52,8 N/mm2
τ TC = τ TD = 6.055Nmm.35,4mm / 5,4.105mm4= 39,70N/mm2
10) The resultant stresses τ RA, = τ RB and τ RA, = τ RB
are obtained by adding the stress vectos graphically as shown below
τ RA = τ RB=46,29 N/mm2
τ RC = τ RD = = 45,31N/mm2
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