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Lifting Lug Calculations Kod

The document analyzes the lifting lugs on a 500 kg piece of equipment. It calculates forces on the lugs from the weight and lifting configuration. It then analyzes stresses in the lug material and welds. All stresses are found to be below allowable limits, indicating the lugs are sufficiently strong for the given lifting scenario. Weld sizes are also calculated and found to exceed requirements.

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anu radha
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682 views2 pages

Lifting Lug Calculations Kod

The document analyzes the lifting lugs on a 500 kg piece of equipment. It calculates forces on the lugs from the weight and lifting configuration. It then analyzes stresses in the lug material and welds. All stresses are found to be below allowable limits, indicating the lugs are sufficiently strong for the given lifting scenario. Weld sizes are also calculated and found to exceed requirements.

Uploaded by

anu radha
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as PDF, TXT or read online on Scribd
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136

LIFTING LUG ANALYSIS

ERECTION WEIGHT, P (Note1) P 50011 N 5098.00 Kgs


SHOCK FACTOR, F : 2

LIFTING LUG DIMENSIONS: RE-PAD DIMENSION:


h= 130 a= 120 LENGTH(l): 150
b= 110 f= 40 WIDTH(w) : 50
di= 40 t1 = 16 THICK.(t): 16
LUG ORIENTATION (A) : 45 tc = 0
SLING ANGLE (B) = 30 dc = 0

LUG FORCES :
VERTICAL LIFTING FORCE, PL = P/4*F = 25006 N
FORCE ALONG SLING, PV = PL/COS(B) = 28874 N
CIRC.FORCE,Pc = PV*COS(90-(A+B)) or COS(B) 27890 N
RADIAL FORCE,Pr = PV*SIN(90-(A+B)) or SIN(B) 7473 N
MATERIAL OF LUG : SA516 GR, 60
YIELD STRESS, Ys= : 220 N/mm 2

ALLOWABLE STRESSES :
TENSILE STRESS,Sa=0.6*Ys : 132 N/mm 2
SHEAR STRESS, Ss=0.4*Ys : 88 N/mm 2
2
BEARING STRESS, Se=0.8*Ys : 176 N/mm
BENDING STRESS, Sb=0.66*Ys : 145.2 N/mm 2

INDUCED STRESSES :

TENSILE STRESS = PV/[(t1*(b-di)+((dc-di)*2*tc 25.78 N/mm 2 <Sa HENCE SAFE


SHEAR STRESS = PV/[2*((t1*(f-ri)+(dc-di)*2*t 45.12 N/mm 2 <Ss HENCE SAFE
2
BEARING STRESS = PV/[di*(t1+2*tc)] = 45.12 N/mm <Se HENCE SAFE
BENDING STRESS = M/Z=Pc*h/(t1*a^2/6)= 94.42 N/mm 2 <Sb HENCE SAFE

Note 1: Weight includes all attachments


137

LIFTING LUG ANALYSIS


(as per bednar ex.10.5 page-275)

STRENGTH OF WELD (LIFTING LUG TO PAD) :

FILLET LEG SIZE (WFp) = 12 mm


TOTAL WELD LENGTH (Wl) = 292 mm
2
LINEAR SECT.MOD.(Z)=2*a^2/6 = 4800.00 mm

UNIT FORCES DUE TO CIRCUMFERENTIAL FORCES


BENDING(f1) = Pc*h/Z = 755.36 N/mm
SHEAR (f2) = Pc/Wl = 95.51 N/mm
UNIT FORCES DUE TO RADIAL FORCES
SHEAR (f3) = Pr/Wl = 25.59 N/mm

REQUIRED WELD SIZE DUE TO COMBINED LOAD


f = sqrt[(f1+f2)^2+f3^2] = 851.26 N/mm

WELD EFFICIENCY = 0.7 (E)


2
WELD STRENGTH, fw = Sa.E = 92.40 N/mm (Sw)
LEG SIZE (WFc)= f/fw = 9.21 mm
AS WFp>WFc, PROVIDED WELD FILLET SIZE IS SUFFICIENT
( GROOVE + 4 FILLET WILL BE PROVIDED. )

STRENGTH OF WELD (LIFTING LUG PAD TO SHELL) :


FILLET ELD THROAT L1 = 8.485 mm
FILLET LEG SIZE (WFp) = 12 mm
TOTAL WELD LENGTH (Wl) = 400 mm
2
LINEAR SECT.MOD.(Z)=2*l^2/6 = 7500.00 mm

UNIT FORCES DUE TO CIRCUMFERENTIAL FORCES


BENDING(f1) = Pc*(h+t)/Z = 542.93 N/mm
SHEAR (f2) = Pc/Wl = 69.73 N/mm
UNIT FORCES DUE TO RADIAL FORCES
SHEAR (f3) = Pr/Wl = 18.68 N/mm

REQUIRED WELD SIZE DUE TO COMBINED LOAD


f = sqrt[(f1+f2)^2+f3^2] = 612.94 N/mm

WELD EFFICIENCY = 0.55


2
WELD STRENGTH, fw = Sa.E = 72.60 N/mm
LEG SIZE (WFc)= f/fw = 8.44 mm
AS WFp>WFc, PROVIDED WELD FILLET SIZE IS SUFFICIENT

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