Main Article Content
This paper focuses on the accuracy of detecting the location of a complexly shaped damage present in a cantilever beam. The study is carried out by involving the finite element method. At first, we have parametrically described the geometry of a branched crack and designed its discrete model. As a further step, we performed simulations to observe the changes in the static and dynamic behavior of the beam that occur in the presence of damage. Several types of Y-shaped cracks have been taken for these analyses. We have shown the beam has a diminished capacity to store energy and consequently the frequency decreases. The frequency shift phenomenon for the first mode of vibration was found to be in concordance with the changes in the deflection of beam’s free end. We derived on this basis a correction coefficient that considers the beam deflections in the intact and damaged state. This coefficient permits predicting the frequency shift due to a given crack. As the last step, we have successfully compared the frequencies achieved directly using the FEM with those for the intact beam to which the correction coefficient was applied.
Journal author rights
In order for Romanian Journal of Acoustics and Vibration to publish and disseminate research articles, we need publishing rights. This is determined by a publishing agreement between the author and Romanian Journal of Acoustics and Vibration. This agreement deals with the transfer or license of the copyright to Romanian Journal of Acoustics and Vibration and authors retain significant rights to use and share their own published articles. Romanian Journal of Acoustics and Vibration supports the need for authors to share, disseminate and maximize the impact of their research and these rights, in Romanian Journal of Acoustics and Vibration proprietary are defined below:
For subscription articles:
Authors transfer copyright to the publisher as part of a journal publishing agreement, but have the right to: Share their article for personal use (manuscript version); retain patent, trademark and other intellectual property rights (including research data); proper attribution and credit for the published work.
For open access articles:
Authors sign an exclusive license agreement, where authors have copyright but license exclusive rights in their article to the publisher. In this case authors have the right to: share their article in the same ways permitted to third parties under the relevant user license; retain patent, trademark and other intellectual property rights (including research data); proper attribution and credit for the published work.
Rights granted to Romanian Journal of Acoustics and Vibration
For both subscription and open access articles, published in proprietary titles, Romanian Journal of Acoustics and Vibration is granted the following rights:
- The exclusive right to publish and distribute an article, and to grant rights to others, including for commercial purposes;
- For open access articles, Romanian Journal of Acoustics and Vibration will apply the relevant third party user licence (Open access licencses) where Romanian Journal of Acoustics and Vibration publishes the article on its online platforms;
- The right to provide the article in all forms and media so the article can be used on the latest technology even after publication;
- The authority to enforce the rights in the article, on behalf of an author, against third parties, for example in the case of plagiarism or copyright infringement.
How to Cite
 Gillich G.R., Praisach Z.I., Abdel Wahab M., Vasile O., Localization of transversal cracks in sandwich beams and evaluation of their severity, Shock and Vibration, Article ID 607125, 2014, DOI: 10.1155/2014/607125.
 Gillich G.R., Gillich N., Birdeanu E.D., Iancu V., Detection of damages in simple elements, Annals of DAAAM and Proceedings of the International DAAAM Symposium, Vol. 20, 2009, pp. 623-624.
 Rao S., Vibration of continuous systems, John Wiley & Sons Inc., New Jersey, 2007.
 Caddemi S., Calio I., Exact closed-form solution for the vibration modes of the Euler-Bernoulli beam with multiple open cracks, Journal of Sound and Vibration 327(2009), pp. 473-489.
 Praisach Z.I., Minda P.F., Gillich G.-R.. Minda A.A., Relative frequency shift curves fitting using FEM modal analyses, Proceedings of the 4th WSEAS International Conference on Finite Differences - Finite Elements - Finite Volumes - Boundary Elements, Paris, 2011, pp. 82-87.
 Zhang K., Yan X., Multi-cracks identification method for cantilever beam structure with variable cross-sections based on measured natural frequency changes, Journal of Sound and Vibration, 387, 2017, pp.53-65.
 Gillich G.-R., Praisach Z.-I., Onchis-Moaca D., Gillich N., How to correlate vibration measurements with FEM results to locate damages in beams, Proceedings of the 4th WSEAS International Conference on Finite Differences - Finite Elements - Finite Volumes - Boundary Elements, 2011, pp. 76-81.
 Sinha J.K., Friswell M.I., Edwards S., Simplified models for the location of cracks in beam structures using measured vibration data. Journal of Sound and Vibration, 251(1), 2002, pp. 13-38.
 Gillich G.R., Praisach Z.I., Onchis M.D., About the effectiveness of damage detection methods based on vibration measurements, International Conference on Engineering Mechanics, Structures, Engineering Geology, International Conference on Geography and Geology – Proceedings, 2010, pp. 214-219.
 Song Y.Z., Bowen C.R., Kim A.H., Nassehi A., Padget J., Gathercole N., Virtual visual sensors and their application in structural health monitoring, Structural Health Monitoring, 13(3), 2014, pp. 251-264.
 Rizos P.F., Aspragathos N., Dimarogonas A.D., Identi-fication of crack location and magnitude in a cantilever beam from the vibration modes, Journal of Sound and Vibration, 138(3), 1990, pp. 381–388.
 Ostachowicz W.M., Krawczuk C., Analysis of the effect of cracks on the natural frequencies of a cantilever beam, Journal of Sound and Vibration, 150(2), 1991, pp.191–201.
 Chondros T.J., Dimarogonas A.D., Yao J., A continuous cracked beam vibration theory, Journal of Sound and Vibration 215(1), 1998, pp. 17–34.
 Gillich G.R., Mituletu I.C., Praisach Z.I., Negru I., Tufoi M., Method to enhance the frequency readability for detecting incipient structural damage, Iranian Journal of Science and Technology - Transactions of Mechanical Engineering, 41(3), 2017, pp. 233-242.
 Gillich G.R., Negru I., Praisach Z.I., Damages influence on dynamic behaviour of composite structures reinforced with continuous fibers, Materiale Plastice, 49(3), 2012, pp. 186-191.
 Gillich G.R., Maia N.M.M., Mituletu I.C., Praisach Z.I., Tufoi M., Negru I., Early structural damage assessment by using an improved frequency evaluation algorithm, Latin American Journal of Solids and Structures, 12(12), 2015, pp. 2311-2329.
 Gillich G.R., Tufoi M., Korka Z.I., Stanciu E., Petrica A., The relations between deflection, stored energy and natural frequencies, with application in damage detection, Romanian Journal of Acoustics and Vibration, 13(2), 2016, pp. 87-93.
 Nitescu C., Gillich G.R., Abdel Wahab M., Manescu T., Korka Z.I., Damage severity estimation from the global stiffness decrease, Journal of Physics: Conference Series, 842(1), 2017, art. 012034.
 Gillich G.R, Frunzaverde D., Gillich N., Amariei D., The use of virtual instruments in engineering education, Procedia - Social and Behavioral Sciences, 2(2), 2010, pp. 3806-3810.
 Gillich G.R., Praisach Z.I., Iancu V., Furdui H., Negru I., Natural Frequency Changes due to Severe Corrosion in Metallic Structures, Strojniški vestnik - Journal of Mechanical Engineering, 61(12), 2015, pp. 721-730.