Ingenieurgesellschaft für
technische Software

Fatigue Analysis

This fully integrated function enables the computation of high-cycle fatigue. It is the result of a cooperation between "German Steinbeis Transfer Center Traffic Engineering (STZ)" and INTES.

The difference between external and fully integrated fatigue analysis is illustrated by the workflow figure on the right.
Some basic characteristics are:

  • Stress based high-cycle fatigue (long term loading, typically >1000 cycles).
  • Multi-axial stress state on structural surfaces (due to FKM guideline and more) is the basis.
  • Support of volume elements
  • A fatigue analysis may follow a (nonlinear) static analysis as well as transient (timehistory) analysis (modal and direct methods). Load collectives, or time functions for load cycles may be used.
  • Classical nodal point or SPR stresses and precise gradients available.
  • High performance implementation (time, memory and I/O optimal, with excellent parallel scaling).

Truck Spring Bracket

The life prediction simulation of a truck spring bracket for 16 torture tracks gives an impression on the handling advantages as well as on runtime gains. Instead of separate fatigue runs for each of the 16 tracks and a final fatigue run on the load collective, everything may be done within a single PERMAS simulation.
Bracket char Bracket bench Machine: 2*Intel Xeon 8260L, 28 Cores, 564 GiB Memory
PERMAS V18 needs 5.5 h with stress export and 4.25 TiB database disk space plus about 1.5-12h for the external fatigue analysis.

With PERMAS-LIFE a speedup in overall process time of approximately factor 2-6 is gained for this example. Disk space is scaled down to 30% during the overall process.

Laminate analysis
Workflow for fatigue analysis

NPSTG
Stress gradient