http://arthra.ugal.ro/handle/20.500.14043/24441 Sat, 04 Apr 2026 07:22:53 GMT 2026-04-04T07:22:53Z http://arthra.ugal.ro/handle/20.500.14043/24794 Muffler Performances Modeling with Boundary Element - Method and Experimental Study Vasile, Ovidiu This paper investigates the acoustic performance of a reactive silencer using Boundary Element Method analysis and experimental techniques. This analysis addresses a research topic of major interest today on how to reduce noise pollution due to vehicles, or pressure vessels of various machinery and equipment involving air ejection as a result of various processes or urban expansion. Modeling procedures for accurate performance prediction had led to the development of new methods for practical muffler components in design. The transmission loss is the more widely used and can be easily computed with a Boundary Element Method analysis. In the present paper the author present an overview of the principles of Boundary Element Method for predicting the transmission loss (TL) of a muffler with two expansion chambers, the pressure distribution on surfaces of the muffler and the principles are compared with the acoustic performances of the experimental study set up. The predicted results agreed in some limits with the experimental data published in literature. The Annals of ''Dunarea de Jos'' University of Galati Fascicle XIV MECHANICAL ENGINEERING ISSN 1224 - 5615 Fri, 01 Jan 2010 00:00:00 GMT http://arthra.ugal.ro/handle/20.500.14043/24794 2010-01-01T00:00:00Z http://arthra.ugal.ro/handle/20.500.14043/24793 Considetations on Using the Virtual Instruments for the Acquisition and Analysis of Experimental Data from Dynamic Systems Panfiloiu, Gheorghe The new slogan “The software is the tool” takes into consideration a new construction principle for the measuring tools and systems, with a brand new architecture. These systems and tools are assembled into a “virtual space” computer programming environment which provides such basic elements of construction. There is a big advantage of this type of measuring system: each human user can build himself an unlimited number of instruments intended to process and to analyze experimental data; these virtual instruments on the basis of dedicated computer applications can meet individual requirements designated to cover an extended domain of analysis. The function of data acquiring of the equivalent real instrument is now taken by a new PC peripheral (DAQ - data acquisition interface). The functions of data conditioning, data analysis and control are completely taken by the existing hardware in the computer and the software package in question. The current instrument system, as a whole, is designed and developed as a part of the computer, making possible the direct use of the computing power and the facilities of the PC. The article presents the virtual instrument developed on ICECON S.A. Bucharest on the basis of LabView® ver. 8.5 from National Instruments. The virtual instrument was used to acquire and to process some experimental data from the dynamic tests of the Bechtel viaduct at KM 29+602,75↔KM 29+801,25 on the Romanian Highway A3 (“Transilvania” highway). Fri, 01 Jan 2010 00:00:00 GMT http://arthra.ugal.ro/handle/20.500.14043/24793 2010-01-01T00:00:00Z http://arthra.ugal.ro/handle/20.500.14043/24792 Dynamical Response Analysis of a System with one Degree of Freedom Stresses by the Different Pulse Excitation Functions Leopa, Adrian; Năstac, Silviu Viscoelastic systems embedded in structures such as bridges are subject to various dynamic loading from traffic. A dynamic study of these structures requires more accurate definition of disturbance function parameters: shape, duration and amplitude. This paper is a theoretical study that analyzes the dynamic response of a system with one degree of freedom with a viscoelastic element embedded (Kelvin rheological model) loaded by various functions of the excitation pulse. In this way it is highlighted the importance of the excitation function shape, in physical and mathematical modeling of technological systems. The Annals of ''Dunarea de Jos'' University of Galati Fascicle XIV MECHANICAL ENGINEERING ISSN 1224 - 5615 Fri, 01 Jan 2010 00:00:00 GMT http://arthra.ugal.ro/handle/20.500.14043/24792 2010-01-01T00:00:00Z http://arthra.ugal.ro/handle/20.500.14043/24791 The Influence of Nonlinear the Elastic Character of Viscoelastic Systems on the Dynamic Response of Mechanical Systems Leopa, Adrian Bridges and viaducts represent vital engineering structures which are component of terrestrial communication lines, therefore reducing their exposure to factor originating from natural or anthropogenic hazards has no optional character, becoming a necessity and a goal of the current modern economy. Combating destructive vibration phenomenon, or in some cases catastrophic, likely to develop in the absence of control techniques, at the running car or during seismic movement of a bridge (viaduct ), is achieved by implementing control systems capable to dissipate the energy accumulated in the system, such as viscoelastic dampers. After prolonged use, these antivibration systems under go structural and functional changes due to viscous and elastic link degradation, thus gaining a nonlinear behavior. This paper represents a theoretical study of the nonlinear behavior influence of the dynamic response of mechanical system in impulsive stress regime. The Annals of ''Dunarea de Jos'' University of Galati Fascicle XIV MECHANICAL ENGINEERING ISSN 1224 - 5615 Fri, 01 Jan 2010 00:00:00 GMT http://arthra.ugal.ro/handle/20.500.14043/24791 2010-01-01T00:00:00Z