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structures), working temperature near to the brittle-ductile transition, indirect evaluation

of fracture characteristics, as e.g. by impact testing.

•

Scheme for the evaluation of operational loads deviate from real one, which is to

complex to be applied.

•

Uncertainties exist concerning the application of NDI and its sensitivity.

•

Characterisation of crack is difficult and the calculated values are uncertain.

•

Time in service can affect the parameters, as it is the case with material properties

•

Loading condition change.

•

Failure consequences are unacceptable.

6. CONCLUSSION

Almost two thirds of the respondents reply positively in an inquiry to the question:

should there be a professional qualification for competence in the application of fracture

mechanics method as fitness-for-service (FFS) technology? Due to the complexity of

materials and high number of simplifications, of which every one introduces some limits

in the application of fracture mechanics methods, proper training and the experience is

certainly necessary. Since the knowledge is not only possessing of information about

certain problem, but creative and responsible approach to the application of available

information (know-how), become clear that frequently opposing information and

requirements should be treated of, adequate experiences and skills are necessary.

Procedures within the structural integrity analysis are techniques by which the fitness-

for-purpose of elements and structures carrying the load and reliable equipment operation

are evaluated. Used an appropriate and correct way these procedures increase general

efficiency preventing excessive sizing and redundant inspection and repairs, providing

balance between economy and the safety requirements for the environment, which are

jeopardized by the consequences of fracture and failure in structure operation.

REFERENCS

P. Agatonović.: Fracture Casa Studies – Basic Principles, in. From Fracture mechanics to

Structure Integrity Assessment, 8th International Fracture Mechanics School in Belgrade/YU

23-27 June 2003. Ed. S. Sedmak and Z. Radaković pp. 159 – 192.

Agatonović, P.: Različite strategije odredjivanja preostale čvrstoćće i veka , Integritet i vek

konstrukcija (2/2001), str. 75-89.

Agatonović, P.: Die Restfestigkeit bestimmen, Spannungs-Dehnungs-Annäherung – ein neues

Verfahren, Materialprüfung 41(1999), pp. 24-30.

Agatonović, P. : KI mittels Spannungs-Dehnungs-Annäherung abschätzen: Verifikation des

Verfahrens, Materialprüfung 41(1999), pp. 77-84.

Agatonović, P.: Development of residual strength evaluation tool based on stress-strain

Approximation, International Journal of Fracture 98, pp. 129-152, Kluwer Academic

Publishers, the Netherlands.

Agatonović, P. and T.K.Henriksen:

“Development of Residual Strength Prediction Tools for

the Structure Integrity of Launchers Based on Elasto-Plastic Fracture Mechanics”

, Conf. on

Spacecraft Structures, Materials and Mechanical Testing, 27-29 March 1996, Noordwijk, The

Netherland, ESA/ESTEC.

Agatonović, P. and M. Windisch: MARC Anwendung zur Untersuchung des

Versagensangerissener Bauteile, MARC Anwendertreffen, 14/15.9.94

Agatonović, P. and U. Clormann:

“Analytical Prediction and Test Verification of the

Multiaxial Behaviour of High-strength Steel for Lightweight Structures”

, Proc. Int. Symp.