http://arthra.ugal.ro/handle/20.500.14043/24595 2026-04-06T11:57:23Z 2026-04-06T11:57:23Z Scheaua, Fănel http://arthra.ugal.ro/handle/20.500.14043/24603 2020-09-03T13:27:47Z 2015-01-01T00:00:00Z

Aspects Regarding Rolling Pendulum Seismic Isolation Systems Scheaua, Fănel Special systems capable to ensure a proper isolation for building structures against dynamic actions have experienced a continuous development in the recent years. These systems are designed to provide increased safety for buildings subjected to destructive dynamic actions such as shocks, vibrations, but also seismic ground motions. Depending on their role within the structural components, this kind of devices may be classified as isolation systems providing isolation against different occurring motion, but also energy dissipating elements. Within the category of isolation systems there is a special mechanical device that can be used for the structure base isolation of bridges or buildings with reduced height. The mounting position is at the base, namely between the foundation and the superstructure. The device works on the principle of pendulum and consists of two metal plates between which there is a spherical piece that performs a rolling motion. This fitting method ensures freedom of movement for the lower part of the device together with foundation and ground, while the upper part together with superstructure tends to remain in the equilibrium position. This paper presents the model of rolling pendulum system (RPS), but also the experimental results obtained on a small-scaled bridge structure isolated with this kind of system. The Annals of ''Dunarea de Jos'' University of Galati : Fascicle XIV : MECHANICAL ENGINEERING, ISSN 1224 - 5615

2015-01-01T00:00:00Z Potîrniche, Aurora Năstac, Silviu http://arthra.ugal.ro/handle/20.500.14043/24602 2020-09-03T13:27:47Z 2015-01-01T00:00:00Z

Correlative Estimations in Using of Effective Configurations for Vibroinsulation Elastomeric Elements Potîrniche, Aurora; Năstac, Silviu This paper deals with practical insulation devices, systems to provide the tradeoff between the contact with earth (in order to resist to gravitation) and the separation from earth (in order to withstand the earthquake). It was proposed to adopt for modeling and analysis an isolation system of HDRB type (high damping rubber bearings) because this system has benefits. Thus, it was chosen for analysis a number of six vibroinsulation elastomeric elements and was studied the behavior of these elements using a specialized software of finite element analysis namely ALGOR. The Annals of ''Dunarea de Jos'' University of Galati : Fascicle XIV : MECHANICAL ENGINEERING, ISSN 1224 - 5615

2015-01-01T00:00:00Z Nedelcut, Florin Scheaua, Fănel http://arthra.ugal.ro/handle/20.500.14043/24601 2020-09-03T13:27:47Z 2015-01-01T00:00:00Z

Geometrical Assumptions Regarding Viscous Fluid Dampers Nedelcut, Florin; Scheaua, Fănel The specific innovative device presented in this paperwork is a hydraulic system operating with viscous fluid that provides damping for shocks and vibrations. A basic viscous fluid device is constructed on the principle of linear hydraulic motor (cylinder with a plunger), but the device presented here has a certain number of orifices made inside the piston head. This allows the fluid circulation during the forced displacement of the piston within the cylinder body, without the need of any external hydraulic connection. Therefore it may be considered to be a passive system that will run without any other attached devices, on a passive principle. Typically, this particular device is used for bridges or viaducts endowment, as connection point between structural elements (base pier and path-way) ensuring in this way a safe anchoring and displacements limitation for the superstructure, especially when unexpected dynamic actions occur. The viscous fluid device operation achieves an energy dissipation role, because it opposes to the relative motion between structural frames, where it was positioned. Due to the viscosity properties of the working fluid, the piston movement is strongly attenuated and the energy received from the environment is partially consumed by the internal viscous friction, then it is transmitted back to the external environment, as heat energy. The value of the diameter of crossing orifices made in the piston head is important for an adequate operation of the viscous fluid device. Therefore, in this paperwork are presented the CFD analysis results obtained for a virtual model of a hydraulic device, when the orifices diameter is changed. The Annals of ''Dunarea de Jos'' University of Galati : Fascicle XIV : MECHANICAL ENGINEERING, ISSN 1224 - 5615

2015-01-01T00:00:00Z Hauk, Niculai http://arthra.ugal.ro/handle/20.500.14043/24600 2020-09-03T13:27:47Z 2015-01-01T00:00:00Z

The Influence of the Hydraulic Fluid Compressibility on the Tematics of Mechanisms Actuated with Hydraulic Cylinders Hauk, Niculai the description of the kinematics of mechanisms driven by hydraulic cylinders, hydraulic agent is usually considered incompressible. This computing hypothesis introduces errors which, in certain situations, can not be accepted. The volume of hydraulic agent sent by hydraulic pump it changes due to its compressibility. As a result, differences appear on the positioning of mobile elements. This paper presents a method of evaluation by calculation of this kind of influence on the positioning accuracy of the moving parts of the mechanism analyzed.

2015-01-01T00:00:00Z