1. Loading by axial force Fx

Resultant Shear Stress

where:

Fx axial force [N, lb].

A throat area of the weld group [mm2, in2].

2. Loading by bending moment M

Shear stress in the weld investigated point

where:

u constant

Calculation of fillet welds loaded in the plane of part joining

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- for calculation in metric units u = 1000

- for calculation in English units u = 12

M bending moment [Nm, lb ft]

r radius vector of investigated weld point related to theweld group center of gravity [mm, in]

J polar moment of inertia of weld group [mm4, in4]

3. Loading by bending force FY

In any weld point, a stress caused by shearing force FY and bending moment MF originates. Its sizedetermines the formula:

MF = FY rF [Nmm, lb in]

where:

FY bending shearing force [N, lb]

rF arm of bending force to the weld group center ofgravity [mm, in].

Shear stress caused by shearing force

where:

Calculation of fillet welds loaded in the plane of part joining

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FY bending shearing force [N, lb]

A throat area of the weld group [mm2, in2].

Shear stress caused by bending moment

- stress x-component

- stress y-component

where:

MF bending moment [Nmm, lb in]

rY distance of investigated weld point to the weld groupcenter of gravity in the y-axis direction [mm, in]

rX distance of investigated weld point to the weld groupcenter of gravity in the x-axis direction [mm, in]

J polar moment of inertia of weld group [mm4, in4]

Resultant shear stress in the investigated point of weld

where:

tXM x-component of shear stress caused by bendingmoment [MPa, psi]

tY shear stress caused by shearing force FY' [MPa, psi]

tYM y-component of shear stress caused by bendingmoment [MPa, psi]

Calculation of fillet welds loaded in the plane of part joining

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4. Loading by common force F

In any weld point, a common force F causes adequate stress to the stress which would arise by combinedloading from bending moment MF and the pair of shearing forces FX', FY' with action point in the weldgroup center of gravity, while applies:

MF = F rF [Nmm, lb in]

FX' = F cos j [N, lb]

FY' = F sin j [N, lb]

where:

F acting force [N, lb]

rF arm of bending force to the weld group center ofgravity [mm, in]

j direction angle of acting force [°]

Shear stress caused by shearing force FX'

Shear stress caused by shearing force FY'

where:

A throat area of the weld [mm2, in2]

Calculation of fillet welds loaded in the plane of part joining

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Shear stress caused by bending moment

- stress x-component

- stress y-component

where:

MF bending moment [Nmm, lb in]

rY distance of investigated weld point to the weld groupcenter of gravity in the y-axis direction [mm, in]

rX distance of investigated weld point to the weld groupcenter of gravity in the x-axis direction [mm, in]

J polar moment of inertia of weld group [mm4, in4]

Resultant shear stress in the investigated point of weld

where:

tX shear stress caused by shearing force FX' [MPa, psi]

tXM x-component of shear stress caused by bendingmoment [MPa, psi]

tY shear stress caused by shearing force FY' [MPa, psi]

tYM y-component of shear stress caused by bendingmoment [MPa, psi]

5. Calculation of comparative stress sS

Calculation of fillet welds loaded in the plane of part joining

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Comparative stress is determined from calculated partial stresses according to the formula:

while for the x-component of stress that actuates in the investigated point of weld, perpendicularly to theweld direction, the aX = a3 formula is applied. In the opposite case aX = a4. The same applies for the y-component of the stress actuating perpendicularly to the weld direction, that is aY = a3 or aY = a4.

where:

tX shear stress caused by shearing force FX' [MPa, psi]

tXM x-component of shear stress caused by bendingmoment [MPa, psi]

tY shear stress caused by shearing force FY' [MPa, psi]

tYM y-component of shear stress caused by bendingmoment [MPa, psi]

a3 conversion factor of weld joint for fillet end weld [-]

a3 conversion factor of weld joint for fillet end weld [-]

Calculation of fillet welds loaded in the plane of part joining

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