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http://hdl.handle.net/123456789/317
2022-01-28T00:56:18ZEXPERIMENTAL STUDY OF THE MATERIAL USED FOR THE HOUSING OF AN ADDER BOX
http://hdl.handle.net/123456789/2581
Title: EXPERIMENTAL STUDY OF THE MATERIAL USED FOR THE HOUSING OF AN ADDER BOX
Authors: Chircan, E.; Scutaru, M.L.; Limbasan, M.M.; Vlase, S.
Abstract: The paper aims to study the material from which a summing box is manufactured that equips a heavy truck, to determine its mechanical properties. In order to achieve the objective of the paper, an experimental set is made, with the help of which the experimental determinations presented in the paper are made.2021-09-30T21:00:00ZTESTING THE MATHEMATICAL RELATION FOR DERIVING THE PATTERNS OF A TRANSVERSAL CRACK IN CANTILEVER BEAMS
http://hdl.handle.net/123456789/2580
Title: TESTING THE MATHEMATICAL RELATION FOR DERIVING THE PATTERNS OF A TRANSVERSAL CRACK IN CANTILEVER BEAMS
Authors: Tufisi, C.; Gillich, G.R.; Lupu, D.; Pop, V.M.
Abstract: The paper presents a method for detecting transversal cracks in steel beams of rectangular cross-section, which is centered on the vibration response of the tested component. We have plotted the relative frequency shift curves for two cantilever beams with different thicknesses, both subjected to a transversal crack of 20% depth. The curves were plotted for several crack positions resulted by removing the crack with a step of 5mm along the beam. As a result, we obtained the crack patterns, which consist of a set of frequency shifts for several out-of-plain vibration modes. We also demonstrate a mathematical relation, which allows the prediction of the frequency drop of beams with transversal cracks. The equation is based on the energies stored in the beam’s section in the undamaged, respectively, in the damaged state. The severity of the damage was calculated from the stiffness of the slice subjected to the biggest bending moment occurred for the beam loaded with dead mass.2021-09-30T21:00:00ZIDENTIFICATION OF FREQUENCIES SPECTRUM OF OLD AND NEW VIOLINS USING DYNAMIC ANALYSIS
http://hdl.handle.net/123456789/2579
Title: IDENTIFICATION OF FREQUENCIES SPECTRUM OF OLD AND NEW VIOLINS USING DYNAMIC ANALYSIS
Authors: Stanciu, M.D.; Mihălcică, M.; Roșca, I.C.; Năstac, S.; Guțăș, V.
Abstract: The paper presents the experimental investigation on old/heritage and new violins in order to determine the frequencies spectrum, quality factor and damping for each structure. The violins, belonging to a violin school (violin Jacobus Stainer, 1716; violin Johann Georg Leeb, 1742; violin Joseph Klotz, 1747; violin Babos Bela ,1920, Gliga 2020), were subjected to dynamic analysis and the results were presented comparatively. From the point of view of the correlation of the frequency response with the anatomical structure of the wood, it was observed that the symmetry of the face construction mostly affects the values of natural frequencies specific to CBR, B1 +, f5 and f6 modes, that increase with the improvement of face symmetry.2021-09-30T21:00:00ZTHE SPECTRAL RESPONSE OF SINGLE-DEGREE OF FREEDOM SYSTEMS WITH STATIONARY RESPONSE
http://hdl.handle.net/123456789/2578
Title: THE SPECTRAL RESPONSE OF SINGLE-DEGREE OF FREEDOM SYSTEMS WITH STATIONARY RESPONSE
Authors: STAN, Petre; STAN, Marinică
Abstract: In many practical applications the system of concern has non-linearities, whitch must be taken into account if one is to predict its performance in a realistic way. For such non-linear problems the classical linear theory, which can be found in a number of text books, is not directly applicabile and new techniques are required. If a non-linear mathematical model of the system under consideration is adopted, together with a random process model of the excitation, then is faced with the problem of predicting the system response. A method for estimating the power spectral density of the stationary response of oscillator with a nonlinear restoring force subjected to external wide band noise excitation has been proposed. The efficiency of the method is checked by comparing results with those numerical simulations. The basic idea of the statistical linearization approach is to replace the original nonlinear system by a linear one. This is done in such a way that the difference between the two systems is minimised in some statistical sense. In this way, the parameters of the linearised system are determined.2021-09-30T21:00:00Z