This is the documentation for the Lifting Lug Design Spreadsheet. Here you will find all information regarding it: how to use, the limitations, fields description, possible troubleshoots, next improvements and so on. So, read it carefully before using it and if you find some problem, come here first to see if there’s a fix or an explanation before contacting me. If you want to know all theory behind this spreadsheet, see this article and if you want to check its validation, click here.
The fields in the spreadsheet is divided as follow:
- Material Properties
All the information regarding the material and process properties. All cells in this block are unlocked.
Information regarding the lug, pin and bushing geometry/dimensions. Need to be used together with the drawing as all the variables in this block can be find there.
- K Factor Chart
Chart that show the relationship between the variables K and e/D.
- Kn Factor Chart
Chart that show the relationship between the variables Kn and D/w.
- Ktru and Ktry Factors Chart
Chart that show the relationship between the variables Ktru, Ktry and hav/D.
- Allowable Load Curve
Chart that show the relationship between the variables Ptr/PtruL and P/PuL.
Calculation of the factors used in the charts. All the cells in this block are locked.
- Oblique Loading
Calculation of the forces and allowable stresses. All the cells in this block are locked.
You can also change the header informations: project name, number of the document, date and revision. Only the page cell is locked.
All the values in the spreadsheet are expressed in SI units:
- Dimensions: milimeters (mm)
- Force: newton (N)
- Pressure and Stress: megaPascal (MPa)
- Temperature: degree celsius (°)
2.1. Material Properties
Beside being called Material Properties, there are fields that are independent from the type of material used and would be better grouped as Process Properties but I thought that it wouldn’t look nice to group only two fields, which is the case of Design Temperature and Load, so just don’t mind it for now.
In the current version (2.34, from 22/11/2018) the user must insert all the material data:
- Lug Material
Trade name of the material used in the lug, like SA-285 C or AISI 304.
- Lug Material UNS Number
It’s a six digit unique code for each material
- Bushing Material
Trade name of the material used in the bushing.
- Bushing Material UNS Number
It’s a six digit unique code for each material. There’s a great book that explain everything about it: Metals and Alloys in the Unified Numbering System (UNS): 13th Edition.
- Percent Elongation of Lug Material
Elongation percentage of the material at break or how much its elongation increase before it break.
- Lug Elastic Modulus
Quantity that measures an object or substance’s resistance to being deformed elastically when a stress is applied to it.
- Bushing Compressive Yield Stress
It’s the value in which the bushing material start to yield when subjected to a compressive axial force.
- Cross Grain Tensile Ultimate Stress of Lug Material
The book says “Cross Grain” but you can use the ultimate tensile stress commonly found in tables and standard codes (in those codes, the test is done appliyng the force in the rolling direction). This field will be later rnamed to just “Tensile Ultimate Stress”.
- Cross Grain Tensile Yield Stress of Lug Material
Sames as the above. Just use the tensile yield stress found in tables and standard codes. This field will be later renamed to “Tensile Yield Stress”.