# Flat tension bar with opposite U-shaped notches

## Values for calculation

$P$ $\mathrm{N}$
$r$ $\mathrm{mm}$
$t$ $\mathrm{mm}$
$H$ $\mathrm{mm}$
$h$ $\mathrm{mm}$

## Calculation

### Coefficient $C_1$

$\text{if }\ 0.1\le t/r\le 2.0$
$$C_1=0.955+2.169\cdot\sqrt{t/r}-0.081\cdot t/r$$
$\text{else}$
$$C_1=1.037+1.991\cdot\sqrt{t/r}+0.002\cdot t/r$$

### Coefficient $C_2$

$\text{if }\ 0.1\le t/r\le 2.0$
$$C_2=-1.557-4.046\cdot\sqrt{t/r}+1.032\cdot t/r$$
$\text{else}$
$$C_2=-1.886-2.181\cdot\sqrt{t/r}-0.048\cdot t/r$$

### Coefficient $C_3$

$\text{if }\ 0.1\le t/r\le 2.0$
$$C_3=4.013+0.424\cdot\sqrt{t/r}-0.748\cdot t/r$$
$\text{else}$
$$C_3=0.649+1.086\cdot\sqrt{t/r}+0.142\cdot t/r$$

### Coefficient $C_4$

$\text{if }\ 0.1\le t/r\le 2.0$
$$C_4=-2.461+1.538\cdot\sqrt{t/r}-0.236\cdot t/r$$
$\text{else}$
$$C_4=1.218-0.922\cdot\sqrt{t/r}-0.086\cdot t/r$$

### Stress concentration factor with the nominal stress based on net area

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

### Nominal or reference normal stress

$$σ_{nom}=\cfrac{P}{h\cdot\left(H-2\cdot t\right)}$$

### Maximum normal stress

$$σ_{max}=K_{tn}\cdot σ_{nom}$$

### Normal stress

$$σ=\cfrac{P}{h\cdot H}$$

### Stress concentration factor with the nominal stress based on gross area

$$K_{tg}=\cfrac{σ_{max}}{σ}$$