Extended proof of fibre-reinforced laminates with holes

• Autorzy: Kroll, L. , Kostka, P. , Lepper, M. , Hufenbach, W.
• Języki publikacji: EN

Abstrakty

EN

Purpose: A calculation method for the strength prediction of tensioned laminated plates with circular notches is presented. Design/methodology/approach: An extensive basis of experimental data from tensile fracture tests on carbon fibre reinforced specimens with circular notches was used to analyse factors determining the notched strength. The proposed extension of the known Whitney-Nuismer and Karlak Point Stress Criteria improves the strength prediction accuracy through introduction of a special coefficient function that takes into account the dependence between stress gradients in the notch near-field and the distance of the outer boundary. Findings: It was found that the theoretical, notch size and outer boundary independent stress concentration factor is not sufficient for a reliable prediction of the notched strength. The presented results show that calculation procedure based on fundamental mechanical relations of the elasticity theory with few experimentally determined factors delivers results which good agree with experiments. Research limitations/implications: The calculation procedure was verified on the representative population of tensile specimens made of several types of carbon fibre reinforced laminates used in the aerospace industry. Practical implications: As openings represent relevant sites of failure in the construction, an accurate calculation of the notched strength is essential for the lightweight-oriented design of fibre-reinforced elements. The presented procedure is relevant for construction of practically important tensioned elements with circular holes. Originality/value: The presented formulation of the phenomenological “characteristic distance” concept and its thorough experimental verification is original.

Słowa kluczowe

PL

wytrzymałość karbu; laminat

EN

notch strength; laminate

• Czasopismo: Journal of Achievements in Materials and Manufacturing Engineering
• Rocznik: 2009
• Tom: Vol. 33, nr 1
• Strony: 41-46
• Opis fizyczny: Bibliogr. 15 poz., rys., tabl.

Twórcy

autor

Kroll, L.

autor

Kostka, P.

autor

Lepper, M.

autor

Hufenbach, W.

• Institute for General Mechanical Engineering and Plastics Technology (IMK), Chemnitz University of Technology, Germany,

Bibliografia

• [1] G. Demelio, C. Pappalettere, Stress field near sharp notches, Journal of Materials Processing Technology 32 (1992) 155-160.
• [2] J. Díaz, L. Rubio, Developments to manufacture structural aeronautical parts in carbon fibre reinforced thermoplastic materials, Journal of Materials Processing Technology 143-144 (2003) 342-346.
• [3] K. Flaga, Advances in materials applied in civil engineering, Journal of Materials Processing Technology 106 (2000) 173-183.
• [4] R. Grimberg, A. Savin, R. Steigmann, A. Bruma, Eddy current examination of carbon fibres in carbon-epoxy composites and Kevlar, International Journal of Materials and Product Technology 27/3-4 (2006) 221-228.
• [5] W. Hufenbach, L. Kroll, Stress analysis of notched anisotropic finite plates under mechanical and hygrothermal loads, Archive of Applied Mechanics 69 (1999)145-159.
• [6] L. Kroll, P. Kostka, M. Lepper, W. Hufenbach, New notched strength criteria for multilayered structures, Proceedings of the 11th International Scientific Conference “Contemporary Achievements in Mechanics, Manufacturing and Materials Science” CAM3S’2005, Gliwice - Zakopane, 2005 (CD-ROM).
• [7] L. Kroll, M. Lepper, B. Grueber, P. Kostka, B. Zhou, Analytical models for stress and failure analysis of notched hybrid composites, Proceedings of the 21st International Congress “Theoretical and Applied Mechanics” ICTAM-21, Warsaw, 2004.
• [8] S. G. Lekhnitskii, Anisotropic Plates, Gordon and Breach Science Publishers, New York, 1968.
• [9] M. Lepper, Kerbspannungsanalyse anisotroper Mehrschicht-verbunde mit symmetrischem und unsymmetrischem Strukturaufbau, Dissertation, TU Clausthal 1999 (in German).
• [10] H. Neuber, Kerbspannungslehre Theorie der Spannungs-konzentration, Genaue Berechnung der Festigkeit, Springer, 2001 (in German).
• [11] R. J. Nuismer, J. M. Whitney, Uniaxial Failure of Composite Laminates Containing Stress Concentrations. in: Fracture Mechanics of Composites, ASTM STP 593, 1975.
• [12] S. Ochiai, M. Tanaka, M. Hojo, Simulation study on interfacial debonding caused by spatially distributed damages in unidirectional fibre composites using 2D model, International Journal of Materials and Product Technology 16/1-3 (2001) 139-148.
• [13] M. Rojek, J. Stabik, S. Sokół, Fatigue and ultrasonic testing of epoxy-glass composites, Journal of Achievements in Materials and Manufacturing Engineering 20 (2007) 183-186.
• [14] B. Smoljan, N. Tomašic, S. Smokvina, Composites in manufacturing of vehicles, Proceedings of the 11th International Scientific Conference “Achievements in Mechanical and Materials Engineering” AMME’2002, Gliwice - Zakopane, 2002, 515-518.
• [15] G. Wróbel, Ł. Wierzbicki, Ultrasonic methods in diagnostics of glass-polyester composites, Journal of Achievements in Materials and Manufacturing Engineering 20 (2007) 203-206.