Relation between Torque and Tension
Relation between Torque and Tension
(OP)
Folks,
Are there any cook book relations between applied torque and tension? I read that the relations are not precise and there a lot of variables in the equation.
I am trying to find out how much bearing pressure is exerted by a nut/washer on a wood member when torque is applied on a expansion anchor that goes through the wood member.
Are there any cook book relations between applied torque and tension? I read that the relations are not precise and there a lot of variables in the equation.
I am trying to find out how much bearing pressure is exerted by a nut/washer on a wood member when torque is applied on a expansion anchor that goes through the wood member.






RE: Relation between Torque and Tension
F= Torque/(c)(d), where c=national fudge factor for friction, thread pitch, etc., d=nominal diameter of the fastener, F=tensile force in the bolt.
"c" is in the range of 0.02 to 0.04 for high strength bolts
I'm sure this relationship is only good for a small range of bolt diameters, probably from about 3/8" to 1", and I backcalculated the relationship from empirical data based on a typical ASTM A325 bolt, 3/4" dia. will require between 350 to 400 ft-lbs of torque to achieve 70 percent of its tensile strength (for clamping force in high strength bolted connections)
This will probably get you in the ballpark.
RE: Relation between Torque and Tension
RE: Relation between Torque and Tension