Advanced Structural Analysis/Part I - Theory/Failure Modes/Plastic Failure/Special Members/Welds/Fillet Welds

Nomenclature

$f_{uc}=$ characteristic ultimate stress of parent material
$f_{euc}=$ characteristic ultimate stress of electrode material
$f_{wd}=$ dimensioning ultimate stress of joint
$\gamma _{n}=$ application partial coefficient
$\phi =$ reduction factor that corresponds to the weld class
$F_{\alpha }=$ transverse load
$F_{||}=$ longitudinal load
$A=$ surface area of investigated cross section
$\alpha =$ angle between transverse load and the investigated cross section

Summary of Formulas

$F_{R||}=0.6Af_{wd}$

$F_{R\alpha }=A{\frac {f_{wd}}{\sqrt {2+cos(2\alpha )}}}$

Where:

$f_{wd}=\phi {\frac {\sqrt {f_{uc}f_{euc}}}{1.2\gamma _{n}}}$ ;if $f_{uc}<f_{euc}$
or,

$f_{wd}=\phi {\frac {f_{euc}}{1.2\gamma _{n}}}$ ;if $f_{uc}>=f_{euc}$

Interaction formula:

$({\frac {F_{S||}}{F_{R||}}})^{2}+({\frac {F_{S\alpha }}{F_{R\alpha }}})^{2}<=1$

Partial Coefficients

$\phi =0.9$ in most cases. $\phi =1$ is acceptable for high quality butt welds.

$\gamma _{n}=1.0,1.1$ or $1.2$ depending on whether failure repercussions are regarded as mild, severe or very severe.