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Effect of Boundary Conditions on the Distribution of Mode I Fracture Toughness along Delamination Front in CFRP Laminates with General Fiber Orientation

Samborski S.

Mechanics and Mechanical Engineering

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2016

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Vol. 20, nr 2

121--127

EN

The paper deals with numerical analysis of the DCB test configuration together with the data reduction scheme described in the ASTM D 5528 Standard for determination of the mode I fracture toughness in case of the laminated composites with mechanical couplings. The numerical analysis based on the FEM approach was performed with the Abaqus software exploiting the VCCT technique. The results show, that the distribution of the Strain Energy Release Rate can be asymmetric and that mode mixity can occur. A need for mode separation procedures and appropriate data reduction schemes has been revealed.

2

Badania symulacyjne piezoelektrycznego dwubelkowego układu pozyskiwania energii elektrycznej

Nowak R., Pietrzakowski M.

Symulacja w Badaniach i Rozwoju

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2015

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Vol. 6, nr 3

185--192

PL

Zaproponowany układ dwubelkowy składa się z generatora z warstwami piezoelektrycznymi i wzmacniacza drgań. Wymuszenie kinematyczne zrealizowano jako harmoniczny poprzeczny ruch podpory. W pracy skupiono się na wpływie parametrów geometrycznych i materiałowych wzmacniacza na efektywność zamiany energii mechanicznej w energię elektryczną. Wyniki otrzymane metodą analityczną i metodą elementów skończonych przedstawiono w postaci charakterystyk amplitudowo-częstotliwościowych generowanego napięcia. Porównano wybrane maksymalne wartości amplitudy napięcia i częstości drgań własnych, zestawiając je w tabelach. Na podstawie oszacowanych błędów względnych stwierdzono poprawność zastosowanego modelu MES.

EN

In this paper the double beam system, which consists of generator (with piezoelectric layers) and resonator, was presented. Excitation was realized by the transverse harmonic movement of the support. The influence of geometrical and material properties of the resonator on the efficiency of conversion from mechanical energy into electrical energy were investigated. Results obtained by the analytical and the finite element method were shown as amplitude-frequency characteristics of the generated voltage. Comparison of the maximum voltage amplitude and the natural frequencies was summarized in the tables. On the basis of relative errors the correctness of the FEM model was confirmed.

3

Experimental Study On Fracture Property Of Double Cantilever Beam Specimen With Aluminum Foam

Kim Y. C., Choi H. K., Cho J. U.

Archives of Metallurgy and Materials

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2015

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Vol. 60, iss. 2B

1151--1154

EN

This study aims to investigate double cantilever beam specimen with aluminum foam bonded by spray adhesive to investigate the fracture strength of the adhesive joint experimentally. The fracture energy at opening mode is calculated by the formulae of British Engineering Standard (BS 7991) and International Standard (ISO 11343). For the static experiment, four types of specimens with the heights (h) of 25 mm, 30 mm, 35 mm and 40 mm are manufactured and the experimental results are compared with each other. As the height becomes greater, the fracture energy becomes higher. After the length of crack reaches 150 mm, the fracture energy of the specimen (h=35 mm) is greater than that of the specimen (h=40 mm). Fatigue test is also performed with DCB test specimen. As the height decreases, the fracture energy becomes higher. By the result obtained from this study, aluminum foam with adhesive joint can be applied to actual composite structure and its fracture property can possibly be anticipated.