# Stepped flat tension bar with shoulder fillets

## Values for calculation

$P$ $\mathrm{N}$
$H$ $\mathrm{mm}$
$h$ $\mathrm{mm}$
$d$ $\mathrm{mm}$
$r$ $\mathrm{mm}$
$L$ $\mathrm{mm}$

## Calculation

### Depth of groove, notch

$$t=\cfrac{H-d}{2}$$

$$0.1\le t/r\le 20$$

### Coefficient $C_1$

$\text{if }\ 0.1\le t/r\le 2.0$
$$C_1=1.006+1.008\cdot\sqrt{t/r}-0.044\cdot t/r$$
$\text{else}$
$$C_1=1.020+1.009\cdot\sqrt{t/r}-0.048\cdot t/r$$

### Coefficient $C_2$

$\text{if }\ 0.1\le t/r\le 2.0$
$$C_2=-0.115-0.584\cdot\sqrt{t/r}+0.315\cdot t/r$$
$\text{else}$
$$C_2=-0.065-0.165\cdot\sqrt{t/r}-0.007\cdot t/r$$

### Coefficient $C_3$

$\text{if }\ 0.1\le t/r\le 2.0$
$$C_3=0.245-1.006\cdot\sqrt{t/r}-0.257\cdot t/r$$
$\text{else}$
$$C_3=-3.459+1.266\cdot\sqrt{t/r}-0.016\cdot t/r$$

### Coefficient $C_4$

$\text{if }\ 0.1\le t/r\le 2.0$
$$C_4=-0.135+0.582\cdot\sqrt{t/r}-0.017\cdot t/r$$
$\text{else}$
$$C_4=3.505-2.109\cdot\sqrt{t/r}+0.069\cdot t/r$$

### Stress concentration factor

$$K_t=C_1+C_2\cdot\left(\cfrac{2\cdot t}{H}\right)+C_3\cdot\left(\cfrac{2\cdot t}{H}\right)^2+C_4\cdot\left(\cfrac{2\cdot t}{H}\right)^3$$

### Nominal or reference normal stress

$$σ_{nom}=\cfrac{P}{h\cdot d}$$

### Maximum normal stress

$$σ_{max}=K_t\cdot σ_{nom}$$