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A CHECK OF CRACK PROPAGATION MODELS

AGAINST TEST RESULTS

GENERATED UNDER TRANSPORT AND MILITARY

AIRCRAFT FLIGHT SIMULATION LOADING

(GARTEUR TP 54)

Produced by

GARTEUR ACTION GROUP SM (AG)04

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SUMMARY

The Group of R e s p n a l e s fo r Structures and Materials identified the need for an evaluation of fatigue crack propgation mdels. This resulted i n a f i r s t collaborative GARTEUR act ivi ty (frun 1979 to 1983)

cccrrp?leted by a follcwon programre carried out frun 1983 to 1987. This

report presents this follcw-on GARTEUR act ivi ty i n which 7 ins t i tu tes and

companies perfomel nummus fatigue crack gmwth t e s t l i f e evaluations using i n total 10 prediction mthods and d e l s . Ttm types of spectrum

loading were consider& : the F-27 transprt spectrum am3 the FALSWW

mi l i t a ry spectrum. A s e t of 89 prediction cases was established allawing for the investigation of spectrum variations, mterials and thicknesses.

sons between predicted and test l ives are presented and analysed. It

is sham tha t a e l s including load interaction effect based on the crack

closure mncept axe l ikely to provide the most accurate predictions. The

collaborative w r k finished with an extra "blirxl predictionsn wrcice similar to the previous wrk accept t h a t the 9 results of tests under A320

spectrum loadings were kept unlrnm before the i r preihctions,

c 3 m z U R ~ f i 4

Prepxed under the auspices of the Responsables fo r

Structwes am3 Materials of the Group f o r Aeronautical

Research. and Technology i n Ewope (CXEBJR)

Page

1 . In-ction. ............................................. ...................... 2 .- ~~ description and milestones

21 - Ptmgmme description ............................... 22 - Mlestones .......................................... 23 - P m c i pants ........................................

3 - AG4 Chck growth database description ..................... 3 1 - F-27 database. ......................................

311 - Description of the F-27 spectrurn and its variations ......... 312 - Fatigue crack propagation test results

.................. 3121 - Constant amplitude tests ................ 3122 - F-27 spectrum test results

32 - FATSEWF database .................................... 321 - Definition of FATSWT spectra ................. 322 - Fatigue crack propagation test results .........

3221 - Constant amplitude tests .................. 3222 - F m spectnnn test results ............

4 - Prediction : Short description of the partxcipant methods and r e d ts ......................................................

41 - Rules for the adjustment of the prediction models .... 42 - BAe wedimom ....................................... 43 - DFVtR predictions ..................................... 44 - IABG predictions ......................................

441 - Linear mode1 (Elber type) ....................... 442 -Wheeler mode1 ................................... 443 - Wille&q -el ................................ 444 - re^^.............................. ...........

....................................... 45 - MEB m c t i o m 451 - Linear awry ................................... 452 - Non linear theory ............................... 453 - Results .........................................

46 - predictions ....................................... ..................................... 47 - aw?A practiom

48 - AMD-HA predictions .................................... ........................ 49 - m t s on prediction re suLts

5 -. Caparison between predictions and test results .............. 6 - Evaluation of the capabilities of the mthods and rabdels f o r

predicting fatigue crack grawth .............................. 61 - The AMD-BA mad ...................................... 62 - The BAE! method..........,.........,..^..................

........................................ 63 - The DFVLR &el

64 - The IABG m e w ....................................... ........................................ 65 - The BE33 m M

66 - The NLR model * m S w ................................. 67 - The CWR& d e 1 ........................................

7 - The "blind predictions" wrcice .............................. 71 - A320 datdbase ..........................................

711 - A320 s p e c ~ a ..................................... 712 - Constant amplitude mterial data ................. 713 - Under spectrum test results ......................

72 - Prediction resu l t s ..................................... 73 - &agarison of predictions to tests .....................

8 - Dismssion ................................................... 9 - Conclusion ................................................... 10 - Acknwld-t .............................................. 11 - Distrifxttion list ...........................................

.................................................. 12 - Wferences