Crack Paths 2006

Fatigue crack propagation in the frame of a hydraulic press

M.Fulland1, H.A. Richard1,2, M.Sander2 and G. Kullmer2

1 Westfälisches UmweltZentrum, Pohlweg 55, 33098, Paderborn, Germany,

e-mail:fulland@fam.upb.de

2 Institute of Applied Mechanics, Universität Paderborn, Pohlweg 47-49, 33098

Paderborn, Germany

ABSTRACT.Within this paper the fatigue crack growth in the frame of a hydraulic

press will be discussed. The crack growth started at a shrink hole in a notch in the

middle part of the frame. The state of stress of the crack is predominantly influenced by

the notch, which induces a Mixed-Mode-loading during the crack growth. The

propagation of the crack will be analyzed with the crack simulation program

A D A P C R A C K 3 wDhi,ch has been developed at the Institute of Applied Mechanics at

Universität Paderborn. This program is able to calculate fully automatic the stress

intensities along a 3D-crack front as well as the crack path and the lifetime of a

structure.

I N T R O D U C T I O N

In the industrial practice the simulation of crack propagation processes by means of

numerical methods, especially the Finite-Element-method, becomes more and more

important. Responsible for this tendency on the one hand side is an increasing amount

of damage caused by crack propagation, that can be found in all fields of mechanical

engineering. Often the optimized exploit of the strength of a structure with respect to

lightweight construction is a governing factor for this, since especially if materials with

a worse crack resistance are used, the probability of crack growth increases with

increasing stresses in a component. On the other hand side also a developing problem

consciousness concerning fracture mechanical issues widely can be observed.

A D A P C R A C K 3 D

For the investigations in this paper the three-dimensional crack growth simulation

program A D A P C R A C Kh3asDbeen used. The general functionality scheme of this

program is given in Figure 1. A D A P C R A C Kco3nsiDsts of three independent modules,

which in combination comprise a fully automatic fatigue crack growth simulation. The

first module N E T C R A C K 3is Dresponsible for all FE-mesh-adjustments, that are

necessary during a simulation. This incorporates the geometry adaptation due to crack