FEM 1.001 (3rd, 1998)

FEM 1.001 (3rd, 1998) 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).

FEM 1.001

To add DIN 15018/ FEM 1.001 standard execute Standard - FEM 1.001 (3rd, 1998) from the main menu. Alternatively, use the Standard context menu:

Standards_FEM

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 E1 to E8.

Load Spectrum:

The load spectrum characterizes the magnitude of the load acting on the component during its total duration of use.

Load Spectrum Remarks
P0 Very light P=0 CCrane by exception loaded with the working load, and as a rule, with very light loads
P1 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
P2 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
P3 Heavy P=1 Crane frequently loaded with the working load

Class of utilization (number of cycles):

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

Element Group (Table T.2.1.4.4):

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 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:

Material_with_yield_and_tensile

If count > 0 then press to edit Yield Stress and Tensile Strength:

By default, the full model is set for the selection, but it is possible edit the selection.

Press Button_gamma to define safety factors for static stress check for individual loads and loads sets should be defined:

The fatigue calculations (2..Fatigue) are performed on Load Group only, stress range from load group is required. Check "3..Fatigue Summation" performs additional calculations and sum damage from different load groups based on stress history defined in Fatigue Group.

Standards_FEM_menu

Static Check

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

FEM_formula_allowable_stress

For the shear direction the allowable stress is divided on √3

Fatigue Check

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

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.

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: