DIN 15018 / FEM 1.001
DIN 15018 / FEM 1.001 performs the static stress check and fatigue check for the steel structures of crane and crane equipment. Fatigue calculations are performed according to the Allowable Stress Design method (ASD).
To add DIN 15018/ FEM 1.001 standard execute
- from the main menu. Alternatively, use the context menu:To perform the fatigue check three classifications should be defined: Weld Type, Element Group and Material Type.
Weld Type - also called Notch Case, determines which elements belong to what weld type (K0-K4 - joints affected by welding, W0-W2 - elements and joints, not affected by welding). Weld Type depends on the shape, structural design, whole pattern or type and quality of the welds.
Element Group - depends on the Load Spectrum and Class of Utilization (number of cycles). Can be set from B1 to B6.
Load Spectrum:
Load Spectrum | Remarks | ||
---|---|---|---|
S0 | Very light | P=0 | Crane by exception loaded with the working load, and as a rule, with very light loads |
S1 | Light | P=1/3 | Crane sometimes loaded with the working load, and as a rule with loads of about 1/3 of the working load |
S2 | Moderate | P=2/3 | Crane repeatedly loaded with the working load, and as a rule with loads between 1/3 and 2/3 of the working load |
S3 | Heavy | P=1 | Crane frequently loaded with the working load |
Class of utilization (number of cycles):
Class of utilization | Number of expected load cycles | Remarks | |
---|---|---|---|
Over | To...incl | ||
N1 | - | 2 x 10^{5} | Irregular use with long periods of rest |
N2 | 2 x 10^{5} | 6.3 x 10^{5} | Regular use in interrupted operation |
N3 | 6.3 x 10^{5} | 2 x 10^{6} | Regular use in continuous operation |
N4 | 2 x 10^{6} | - | Full, continuous operation |
Element Group:
Design load spectrum | Class of utilization | |||
---|---|---|---|---|
N1 | N2 | N3 | N4 | |
S0 | B1 | B2 | B3 | B4 |
S1 | B2 | B3 | B4 | B5 |
S2 | B3 | B4 | B5 | B6 |
S3 | B4 | B5 | B6 | B6 |
For FEM 1.001 standard can be set from B1 to B6.
Symbol | Total duration of use number n of stress cycles) | ||||
---|---|---|---|---|---|
B0 | n | ≤ | 16 000 | ||
B1 | 16 000 | < | n | ≤ | 32 000 |
B2 | 32 000 | < | n | ≤ | 63 000 |
B3 | 63 000 | < | n | ≤ | 125 000 |
B4 | 125 000 | < | n | ≤ | 250 000 |
B5 | 250 000 | < | n | ≤ | 500 000 |
B6 | 500 000 | < | n | ≤ | 1 000 000 |
B7 | 1 000 000 | < | n | ≤ | 2 000 000 |
B8 | 2 000 000 | < | n | ≤ | 4 000 000 |
B9 | 4 000 000 | < | n | ≤ | 8 000 000 |
B10 | 8 000 000 | < | n |
Stress Spectrum class | Class of utilization | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
B0 | B1 | B2 | B3 | B4 | B5 | B6 | B7 | B8 | B9 | B10 | |
P1 | E1 | E1 | E1 | E1 | E2 | E3 | E4 | E5 | E6 | E7 | E8 |
P2 | E1 | E1 | E1 | E2 | E3 | E4 | E5 | E6 | E7 | E8 | E8 |
P3 | E1 | E1 | E2 | E3 | E4 | E5 | E6 | E7 | E8 | E8 | E8 |
P4 | E1 | E2 | E3 | E4 | E5 | E6 | E7 | E8 | E8 | E8 | E8 |
Material Type - define which steel is used St37 or St52.
Formulas of DIN15018 / FEM 1.001 standard use Yield Stress and Tensile Strength from the materials. It is important to set this value for each material. Standard check if Yield Stress or Tensile Strength is not equal to zero:
If count > 0 then press to edit Yield Stress and Tensile Strength:
Create Tables and Plots for Loads - creates the standard tables and plots for Overall Check for the selected Loads.
By default, the full model is set for the selection, but it is possible edit the selection.
DIN15018 / FEM 1.001 standards perform calculations fatigue only on the Load Groups, because the calculation procedure requires the usage of the difference in stress among the loads. For static stress safety factors for individual loads and loads should be defined:Mathematical background
Static Check
For DIN15018 standard the allowable static stress check equal to the minimum of material yield stress and 70% of tensile strength:
For the FEM 1.001 standard the allowable stress is limited <0.7. For steels with high elastic limit allowable stress is corrected with formula in chapter 3.2.1.1
For the shear direction for both standards the allowable stress is divided on √3
Allowable fatigue stress is divided on coefficient (depends on direction and weld type):
Coefficient = 1 – for the normal and equivalent stresses.
Coefficient = – for the shear stress with the weld classification K0-K4.
Coefficient =– for the shear stress the with weld classification W0-W2.
Smin and Smax -minimum and maximum values of calculated result stresses;
The Kappa factor is the ratio between minimum and maximum stresses:
For K-factor [-1;0]:
For K-factor (0;1]:
Where Sf – the allowable stress fatigue when K=-1. The Stress fatigue can be set by the exact value or by setting the crane group and the weld type.
Utilization factor fatigue (is calculated for the directions X, Y, Z, XY, YZ and ZX):
Combined utilization factor fatigue is calculated using the following formula (the sign of Ufx, Ufy and Ufz are taken into the account) :
Maximum Utilization factor fatigue: