Pull Out Force Calculation in Aluminum
Pull Out Force Calculation in Aluminum
(OP)
Have done a lot of reading on the 'net trying to find a definitive answer for calculating the Pull Out Force of a screw in Aluminum.
Here are the knowns
5/16-18 SHCS Class 2 Gr 8
6061 Aluminum plate 3/4" thick (40ksi ?)
Length of engagement = 5/8"
On another site (engineersedge.com) there is reference to a formula for calculating Stress Area of a given Screw & corresponding female thread that makes use of the data from Machinery's Handbook.
http:// www.engine ersedge.co m/thread_s trength/th read_bolt_ stress.htm
The referenced formula is also set up for direct user input by clicking on the link at the bottom of that page.
Going through the calculations, I arrived at .4663sqin for the Stress Area and a Pull-Out of 18,651# (using 40ksi)
The online calculator gives the same numbers.
The 18k + number seems quite large,...is this a valid number?
Even though this isn't a hanging load, should a "safety factor" be used with this? 50% rating?
What's the general consensus on this type of application?
Thanks for any input
Willie
Here are the knowns
5/16-18 SHCS Class 2 Gr 8
6061 Aluminum plate 3/4" thick (40ksi ?)
Length of engagement = 5/8"
On another site (engineersedge.com) there is reference to a formula for calculating Stress Area of a given Screw & corresponding female thread that makes use of the data from Machinery's Handbook.
http://
The referenced formula is also set up for direct user input by clicking on the link at the bottom of that page.
Going through the calculations, I arrived at .4663sqin for the Stress Area and a Pull-Out of 18,651# (using 40ksi)
The online calculator gives the same numbers.
The 18k + number seems quite large,...is this a valid number?
Even though this isn't a hanging load, should a "safety factor" be used with this? 50% rating?
What's the general consensus on this type of application?
Thanks for any input
Willie





RE: Pull Out Force Calculation in Aluminum
A conservative value for shear strength is 0.577xUTS.
And yes use a factor of safety depending on the application. How important is it for it not to fail? Also you should consider fatigue if it is to have repeated loading/unloading and for Aluminum there is no endurance limit.
RE: Pull Out Force Calculation in Aluminum
Your force would be ~ 15 000 pounds.