Lifting lug calcs.xls



Check lug shear stress.

Check Bending and tension stress.

Check bearing stress.

Check weld size.

Calculation Reference
Machine Design
Strength of Welds
Design of Lifting Equipment

Calculation Preview

Submitted On:
21 Mar 2011
File Size:
39.50 Kb
File Version:
File Author:
Steve Haberli

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Comments: 7
amrtarek3010 11 months ago
cstrain 9 years ago
I don't know if it is addressed in this thread, but G16 has an error in it regarding the calculation of the horizontal component of the load based on theta. I believe the equation should be G18*cos(G17*PI()/180)
JohnDoyle[Admin] 9 years ago
I am sorry pgrahn I thought it was a question only relating to cell D59 regarding the combined stress but I now realise the question relates to cell D31 and I must say I am a little perplexed too. The first two terms seem fine but I am not at all sure what the third term in the equation is doing. To my mind there seems to be confusion between the resultant force Fr and vertical and horizontal components Fv and Fh. I hope that the author shaberli can shed some light on the calculation but I would be extremely cautious about its use in my own calculations. There are many other lug calculations on the site with good ratings and feedback perhaps you should take a look to them?
pgrahn 9 years ago

The equation seems appropriate. My concern is the coding in the excell spreadsheet in which leaving out the parenthesis makes a significant difference.
Without the parenthesis in the denominator the numerator is only divided by "W" and not "(W*(t^2/6)).
The author may have multiplied t instead of squared t as well.
JohnDoyle[Admin] 9 years ago
The formula for combined stress seems to be an approximation for either the maximum principle stress or twice the maximum shear stress. Both of which are used for failure criterion. I do not think it is a mistake. You could study further using Biaxial Stress Assessment.xls. A set of brackets is redundant in the formula but this matters little to the result. It will be interesting to see calculation author's comments.
pgrahn 9 years ago
I have a question/concern about calculating the Bending + Tension Stress (Longitudinal)equation.
In the denominator of the last equation it has "(W*(t2/6)"...
Is that t^2 or t*2?
Also in the excell equation is leaves out a set of parenthesis.
These two possible errors results in dramatic changes in the equation.
JohnDoyle[Admin] 10 years ago
Hi I am an ExcelCalcs website administrator. Could you explain the problem you are having and I can try to help you. What are you trying to do?
barangeravindra emailed saying:
We try to help as best we can but we simply do not have enough time to answer such detailed questions from free subscribers. However our calculations previews in this folder show the equations you are looking for. Please feel free to copy the formulas into your own spreadsheet.