 # I get the message in RF‑/PLATE‑BUCKLING, saying that the distance between stiffeners exceeds the minimum requirement. What should I do?

The message shown in Figure 01 is displayed if you select the "Minimum distance between stiffeners: 30 ε t" check box in Details and the clear distance between the stiffeners is smaller than this minimum distance amin. The minimum distance is calculated as follows:

amin = 30 ⋅ ε ⋅ t

where

ε = √(235 / f[N/mm²])
fy is the yield strength,

t is the thickness of the buckling panel.

In this case, the distance of the stiffeners must be increased in Window "1.2 Stiffeners." For the buckling panel shown in Figure 01, the clear distance between the stiffeners is:
Δz = z2 - z1 - (t1 + t2) / 2 = 890 - 600 - (10 + 10) / 2 = 280 mm

This distance is smaller than the minimum distance:
amin = 30 ⋅ ε ⋅ t = 30 ⋅ √(235 / 355) ⋅ 12 = 292.9 mm

Therefore, the position of Stiffener 2 should be entered at least
z2 = z1 + (t1 + t2) / 2 + amin = 600 + (10 + 10) / 2 + 292.9 ≈ 903 mm

This distance is also displayed as information in Window "1.2 Stiffeners" when placing the mouse pointer over Stiffener 2 (Figure 02).

If the calculation should also be performed for a stiffener distance smaller than the minimum distance, the "Minimum distance between stiffeners: 30 ε t" check box must be deactivated (Figure 03).

#### Keywords 