Bevel Weld Stress Calculations

[gordohongo112]

I need to do some weld calcs for a rod welded to a pin eye using a bevel groove weld all around.

the rod end has a chamfer that has a bevel angle of 30 degrees and a horizontal length of 1/8. i'm treating the pin eye as a flat surface.

i'm comparing the maximum allowable material loads using the filler materials ult strength, and the two base metal yield strengths.

for the base metals i'm using the formula's:
max allow. load = .4 * material load * surface area.

for the filler material i'm using the formula:
max allow. load = .3 * tensile strenght of filler * face area.

i then figure out the safety factor by dividing the allow strenghts with the applied load.

My question is, can this method be used in this application? or is there another method to calculate the safety factor for this application.

 

[metengr]

gordohongo112;
Please keep your posts to one forum. Second, see below;

for the base metals i'm using the formula's:
max allow. load = .4 * material load * surface area.

Incorrect. Your allowable load above should be based on yield strength as the controlling strength property to avoid permanent or plastic deformation of the eye and rod under tensile and shear loading conditions, which you failed to mention.

for the filler material i'm using the formula:
max allow. load = .3 * tensile strenght of filler * face area.

This is not totally correct. You need to calculate the load carrying capacity of the bevel weld. This should be done by determining the effective throat x treating the circumferential weld as a line. The load carrying capacity can be calculated by multiplying the filler metal tensile strength by a weld reduction factor, even using your conservative value of 0.3. For shear load a typical WSR factor would be 0.49 and for tensile load it is 0.8.


You also need to consider load conditions - static or dynamic?

 

[gordohongo112]

meteng: sorry didn't know where to post...

 

[gordohongo112]

Load Conditions are Static and the cylinder will be loaded in tension.

 

[gordohongo112]

sorry i made a typo,

for the base metals i'm using the formula's:
max allow. load = .4 * material YIELD * surface area.

for the filler material i'm using the formula:
max allow. load = .3 * tensile strength of filler * face area.

 

[gordohongo112]

metengr: i was wondering where i could obtain those reducing factor number, just becuase i need to refrence them in my calcs.

thanks.

 

[metengr]

gordohongo112;
If you need to have specific values you can defend, I would use AISC values like below.

WRF for tension - 0.75* UTS
WRF for shear 0.6 * 0.75 UTS

 

[gordohongo112]

what do you mean by .6*.75 UTS

 

[metengr]

.6 x .75 x ultimate tensile strength = allowable shear strength

.75 x ultimate tensile strength = fracture strength