Crack Paths 2006

a1 crack (R=0.5)

a2 crack (R=0.5)

N A S G RreOlationship 8090T81R=0.5

1.E+00

1.E-01

1.E-02

/cycle ]

1.E-03

d a /d N [ m m

1.E-04

1.E-05

1.E-06

1.E-07

1.E-08

1.E-02

1.E-01

1.E+00

'K/KC

Figure 8 – Comparison between the experimental F E Mdata

with the behavior of the material

Fromthe research results, it is possible to state that:

x The fully numerical method for the structural design of the component give

valid advice for the crack propagation and thus for the damage tolerance

assessment of the panel.

x With a relative opportune safety factor is possible to use the material data,

together with a detailed F E Mmodel, to predict the crack propagation on the

structural panels.

R E F E R E N C E S

1. Federal Aviation Administration, “Part 29- Transport Category Rotorcraft”, USA,

1991

2. Jata, K. V., Starke, E. A. (1986) J. Metal Trans. 17A, 1011

3. Venkateswara, K. T., Ritchie, R. O., (1988) J. Metal Trans. 19A, 563

4. Broek, D., “Elementary Engineering Fracture Mechanics”, Kluwer 1986

5. Slingeland V.O., Broek, D., “ Fatigue crack approaching circular holes” Delft Univ.

Report, 1973

6. A S T ME647-05 “Standard test method for measurement of fatigue crack growth

rates”, U S A2005

7. N A S G R O4.11, “Fracture Mechanics and Fatigue Crack Growth Analysis

Software”, Reference Manual, N A S AJohnson Space Center 2004

8