Calculation of bolted connections

Here you can find online calculation of screw connections.

Bracket calculation

This algorithm calculates normal and tangential loads from bracket to bolts located in one row. It does not take into account the tightening force. The bracket in the calculation is absolutely rigid. To calculate the tensile forces and equivalent stresses in the bolts whith the tightening and friction forces, the obtained load values ​​must be entered into the calculation program for the tightening of the screw connection.

Initial data:

n – number of bolts;

l1 – distance from the pivot point to the first bolt, millimeters;

l2 – distance between bolts, millimeters;

F1 – horizontal component of the load, newtons;

F2 – vertical component of the load, newtons;

L – bracket length, millimeters;

Н – arm of force, millimeters.

К – serial number of the bolt (from the pivot point).


Number of bolts, n

Distance to first bolt l1, mm

Distance between bolts l2, mm

Load F1, N

Load F2, N

Bracket length L, mm

Arm of force H, mm

Serial number of the bolt, k

Normal reaction Pn, N

Tangent reaction Pк, N

bracket calculation
bracket calculation

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Normal component of reaction:

Рni = F1×H×li / ∑ li 2 + F2×L×li / ∑ li 2;

Tangent component of the reaction:

Рк = F1 / n.

Tightening screw connection calculation

The calculation of screw connection is made for bolts of normal accuracy.

Initial data:

d – nominal screw diameter, millimeters;

h – thread pitch, millimeters;

М – thread tightening torque, newtons × meter;

μ – friction coefficient;

Fn – normal component of the load, newtons;

Fк – tangential component of the load, newtons;

L – joint thickness, millimeters;


Nominal thread diameter d, mm

Thread pitch h, mm

Torque M, N*m

Friction coefficient μ

External normal load Fn, N

External tangential load Fk, N

Joint thickness L, mm

Tensile force in the bolt F, N

Equivalent stress σ, MPa

Joint tightening factor (should > 1)

screw calculator
screw calculator

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Other calculators

– key calculation

– slot calculation

– flange calculation

– pin calculation

– interference fit calculation

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