bolt. Clamp load (lb.) is calculated by arbitrarily assuming usable bolt strength is 75% of bolt proof load (psi) times tensile stress area (sq. in.) of threaded section of each bolt size. Higher or lower values of clamp load can be used depending on the application require-ments and the judgement of the designer. 3. Tensile strength (min psi) of all Grade 7 bolts is 133,000. Proof load is 105,000 psi. 4.
How is bolt clamp load calculated?
bolt. Clamp load (lb.) is calculated by arbitrarily assuming usable bolt strength is 75% of bolt proof load (psi) times tensile stress area (sq. in.) of threaded section of each bolt size. Higher or lower values of clamp load can be used depending on the application require-ments and the judgement of the designer. 3. Tensile strength (min psi) of all Grade 7 bolts is 133,000. Proof load is 105,000 psi. 4.
How do you calculate bolt stress?
Bolt stretching according Hook's Law can be calculated as. dl = F L / E A (1) where. dl = change in length of bolt (inches, m) F = applied tensile load (lb, N) L = effective length of bolt where tensile strength is applied (inches, m) E = Young's Modulus of Elasticity (psi, N/m2) A = tensile stress area of the bolt (square inches, m2) strain.
How to calculate prevailing torque?
How is bolt tightening torque calculated?
- normal dry: K = 0.2.
- nonplated black finish: K = 0.3.
- zinc-plated: K = 0.2.
- slightly lubricated: K = 0.18.
- cadmium-plated: K = 0.16.
How much torque for bolts?
The required bolt clamping force for a joint is 20000 lbs. The torque required for a 3/4" dry steel bolt with 0% lubrication to achieve this tension can be calculated as The proof load for a M30 metric bolt grad 8.8 is 337000 N. The torque required to achieve this tension with a dry bolt with 0% lubrication can be calculated as
How is clamp load measured?
Clamp load is the parameter that determines the function of a threaded joint. It is, literally, the force that is holding the joint together. It is possible to measure clamp load by inserting a load measuring washer into the application but this is necessarily a modification of the joint.
What is clamp load on a bolt?
What is Clamp Load? Threaded fasteners act as springs which are preloaded by turning them, clamping two or more objects together until their compression stiffness exceeds that of the tensile stiffness of the bolt.
How do you know what clamping force you need?
The required clamping force can be calculated from the cavity pressure inside the mold and the shot projected area, on which this pressure is acting. There are variables that affect the clamping force calculation, like the material type (low-flow versus high-flow plastic), and the depth of the part.
Does clamping force increase with number of bolts?
AS you point out, the time to assemble the device is mostly governed by the number of bolts rather than their size - for a given length of thread - a large bolt is actually faster to tighten. So this also favors fewer, larger bolts. As for a formula governing the clamping force, it's nothing too special.
What is proof load and clamp load?
Proof load is defined as the maximum tensile force that can be applied to a bolt that will not result in plastic deformation. A material must remain in its elastic region when loaded up to its proof load typically between 85-95% of the yield strength. Acceptable clamp load is typically 75% of proof load.
Is clamping force the same as torque?
At best, torque is an indirect measurement of the tension applied to the bolt. Clamp, defined as the load on the joint brought about by the drawing together of the fastener components, is virtually unrelated to torque.
How do you calculate bolt force?
2:404:38how to calculate bolt tightening torque - YouTubeYouTubeStart of suggested clipEnd of suggested clipThen we can load the bolt up to 90 percent of the proof strength therefore in case of permanentMoreThen we can load the bolt up to 90 percent of the proof strength therefore in case of permanent bolted joint tree load can be calculated as 0.90 times proof strength multiplied by the pole stress.
How do you convert torque to clamping force?
The general formula related to torque is T = KDF (1) where T is the torque, K, the nut factor, and D, the screw diameter, and F, the clamping force. T, K, and D, combine to provide the axial clamping force “F” between the two parts being assembled.
How do you calculate the pull force of a bolt?
To do it, use the formula F = D x 3.1415 x L x 1600 psi -- where F is bolt pull-out force -- D is the bolt diameter in inches -- and L is the length of the bolt embedded in grout. Calculate the pull-out strength for an anchor bolt embedded in concrete.
How do you calculate proof load?
2:443:50proof load and offset yield strength - YouTubeYouTubeStart of suggested clipEnd of suggested clipPercent of original gauge length. The value of the offset percentage of strain is arbitrarily. AndMorePercent of original gauge length. The value of the offset percentage of strain is arbitrarily. And defined by the material testing standard being used like astm. Or iso the most common offset is 0.2.
How is bolt shear capacity calculated?
1:144:51How to calculate the capacity of a bolt subjected to shear force - YouTubeYouTubeStart of suggested clipEnd of suggested clipTimes the hole diameter. And the minimum distance from the center of a hole to the edge of theMoreTimes the hole diameter. And the minimum distance from the center of a hole to the edge of the member is 1.2. Times the hole. Diameter.
What is clamping force in torque?
0:092:43Torque vs Clamp Force - YouTubeYouTubeStart of suggested clipEnd of suggested clipForce. When standard 30 weight oil is applied to the stud without oiling the flange nut 470 foot-MoreForce. When standard 30 weight oil is applied to the stud without oiling the flange nut 470 foot-pounds of torque generated 30,000 pounds of clamping force.
Bolt Torque Calculator
The calculator below can be used to calculate the torque required to achieve a given axial bolt force or load. The calculator is generic an can used for imperial and metric units as long as the use of units are consistent.
Example - Required torque for tightening a Imperial bolt
The required bolt clamping force for a joint is 20000 lbs. The torque required for a 3/4" dry steel bolt with 0% lubrication to achieve this tension can be calculated as
Example - Required torque for tightening a Metric bolt to proof load
The proof load for a M30 metric bolt grad 8.8 is 337000 N. The torque required to achieve this tension with a dry bolt with 0% lubrication can be calculated as
Bolt Force vs. Torque
The proof load for a M30 metric bolt grad 8.8 is 337000 N. The torque required to achieve this force with a dry bolt is calculated to 2022 Nm.
How wide are standard nuts?
Width across the flats of standard nuts is about 1.5 to 1.6 times the nominal thread diameter. This is actually a compromise between strength and size, as a ratio of nearly 2-to-1 is required to eliminate dilation. Nuts are available in larger widths and lengths when required.
Why are threaded fasteners used?
One reason threaded fasteners are so widely used is that they can generate a tremendous amount of clamp load in a small area. Clamp load is central because it is the mechanism by which joint components are held together without moving relative to one another—arguably the primary requirement of a structural joint.
What is the impact of incomplete threads?
As with incomplete threads, the impact is greater the smaller the length-to-diameter ratio. Because the radial dimensions of thread engagement are quite small, small dimensional changes in either internal or external threads can have a measurable impact on load capacity.
