Numerical simulation of fatigue delamination growth under mode I loading conditions

• Autorzy: Bajurko P. , Czajkowska K. , Czarnocki P. , Szeląg D.
• Języki publikacji: EN

Abstrakty

EN

Delaminations are common defects that deteriorate strength of laminates. Delaminations can arise in the course of manufacturing due to faulty fabrication process or can result from low energy impacts, (e.g. FOD), that can take place in service. Once a delamination has been detected, a question will arise whether the defective component can still stay in service or should be immediately repaired or replaced. Before the decision is made, one of the factors that must be considered is a possible delamination growth rate under the expected service cyclic loading. One of the most effective tools that help to answer this question is a numerical simulation of delamination growth. Relatively easy way to simulate fatigue delamination growth under Mode I loading conditions is presented. The a=f(n) relationship was simulated. The simulation was performed with the help of FEM. The delamination extension resulted from gradual reduction in the stiffness of cohesive elements of length t that were located along the expected delamination path. It was assumed that the delamination would extend by delta a=t if the cohesive element stiffness dropped to 0. The applied degradation procedure of the initial mechanical properties of the cohesive elements was based on Paris low. For each delamination, extension increment the degradation process was limited to the cohesive element adjacent to the delamination front. In case of laminates, so far, there is no standard procedure available to determine Paris low and the one used to determine it for the purpose of the simulation performed is presented, as well. The simulation was ended when the number of cycles simulated exceeded 1000 000. The numerical results were verified against the experimental ones resulting from the four specimens tested and a satisfactory agreement was found. The difference between the a=f(n) relationship obtained by the simulation and the one being the average of the four tests was smaller than the scatter of the tests results.

Słowa kluczowe

EN

polymeric composite; fatigue delamination; numerical simulation; fatigue test; Paris-Erdogen relationship

• Wydawca: Łukasiewicz Research Network - Institute of Aviation ; European Science Society of Powertrain and Transport KONES Poland ; Wydawnictwo Instytutu Technicznego Wojsk Lotniczych
• Czasopismo: Journal of KONES
• Rocznik: 2012
• Tom: Vol. 19, No. 2
• Strony: 17--24
• Opis fizyczny: Bibliogr. 8 poz., rys.

Twórcy

autor

Bajurko P.

autor

Czajkowska K.

autor

Czarnocki P.

autor

Szeląg D.

• Institute of Aviation Krakowska Av. 110/114 ,02-256 Warsaw, Poland tel.: [phone], fax:+ 48 22 8462912,

Bibliografia

• [1] ASTM E647-08, Standard Test Method for Measurement of Fatigue Crack Growth Rates.
• [2] Bruner, A. J, Murphy., Pinter, G., Development of a standarized procedure for the characterization of interlaminar delamination propagation in advanced composites under fatigue mode I loading conditions, Engineering Fracture Mechanics, 76, pp. 2678-2889, 2009.
• [3] Harper, P. W., Hallett, S. R., A fatigue degradation law for cohesive interface elements – Development and application to composite materials, International Journal of Fatigue, Vol. 32, I. 11, pp. 1774-1787, 2010.
• [4] Riccio, A., Scaramuzzino, F., Perugini, P., Embedded delamination growth in composite panels under compressive load, Composites Part B32, pp. 209-218, 2001.
• [5] Roe, K. L., Siegmund, T., An irreversible cohesive zone model for interface fatigue crack growth simulation, Engineering Fracture Mechanics, 70, pp. 209-232, 2003.
• [6] Sheinman, I., Kardomateas, G. A., Pelagri, A. A., Delamination growth during pre-and postbuckling phase of delaminated composite laminates, Int. Journal of Solids and Structures, Vol. 35,No. 1-2, pp. 19-31, 1988.
• [7] Turon, A, Costa, J., Camanho, P. P., Da´vila, C. G, Simulation of delamination in composites under high-cycle fatigue, Composites: Part A 38, pp. 2270–2282, 2007.
• [8] Whitcomb, J. D., Analysis of a laminate with a postbuckling embedded delamination, including contact effects, Journal of Composite Materials, Vol. 26, No. 10, pp.1523-1535, 1992.