Hanging load from threads
Hanging load from threads
(OP)
I have a problem where I need to determine if 4 grade 8.8 M36x4.0 bolts can be THREADED into (not nut & bolted) a block of steel which weighs 10,000# and hole the load when suspended from these bolts. I am not sure how to determine load values when the load is hanging from the threads. I would like a formula if possible not just the answer so I can use it in the future for other problems. I would also like to know how to determine the minimum thread engagement needed to get full load potential. Thanks a lot.





RE: Hanging load from threads
If you have a long time to wait the below will link you up to manual on fasteners.
http://gltrs.grc.nasa.gov/cgi-bin/GLTRS/browse.pl?1990/E-4911.html
For a direct formula for engagement length see the Machinery's handbook section on threads.
RE: Hanging load from threads
Try the following threads at this site:
Thread725-18825, Thread288-20937, Thread725-22078, Thread727-22951, and Thread288-21503
Try these websites:
http://euler9.tripod.com/fasteners/
Warning - Big File Here
http://astimage.daps.dla.mil/docimages/0001/34/77/H28-2B.PD9
Lastly, the most informative source for information regarding bolted joints is VDI 2230, Systematic Calculation of High Duty Bolted Joints. Read more at
http://www.vdi.de/vdi/vrp/richtlinien/02842/index.php
RE: Hanging load from threads
1. Minimum Cross-Section of Bolt. The bolt must
satisfy the following two criteria:
Criterion 1: MS = PA t /(SF x P) - 1 ≥0
Criterion 2: MS = PA t /P b - 1 ≥0
2. Shear Pull-Out of Threads. If an internal thread
(nut, nut plate, tapped hole, etc.) is used that is not guaranteed to develop the full ultimate load capability of the bolt, or if the internal thread is not fully threaded onto the bolt, the following two criteria must be met:
Criterion 1: MS = PA s /(SF x P) - 1 ≥ 0
Criterion 2: MS = PA s /P b - 1 ≥ 0
NOTE: These two criteria need only be checked at ultimate load.
b. Shear Load:
MS = VA/(SF x V) - 1 ≥ 0
c. Bending Load:
MS = MA/(SF x M) - 1 ≥ 0
d. Combined Axial, Shear and/or Bending Load:
If the bolt is subject to a combination of loads, the following relationship must hold true for both maximum and minimum preload.
(R a + R b /K)2 + R s 3 ≤1
1 ≤K ≤K y
Where
K y = 1.0 for minimum preload
K y = A plastic bending factor based on actual material stress-strain curves and calculated such that permanent strains do not exceed 0.2% for maximum preload
R a = Ratio of axial load to axial load allowable
and is chosen as the maximum of
(SF x P)/PA t ; P b /PA t ; PLD max /PA t
R b = Ratio of bending load to bending load
allowable,
= (SF x M)/MA
R s = Ratio of shear load to shear load
allowable,
= (SF x V)/VA
NOTE: The axial and shear load allowable (PA t and VA) in this interaction equation are based on the cross-section at which the combined loads occur.
RE: Hanging load from threads