http://arthra.ugal.ro/handle/20.500.14043/24604 2026-04-04T13:55:09Z 2026-04-04T13:55:09Z Năstac, Silviu http://arthra.ugal.ro/handle/20.500.14043/24622 2020-09-03T13:27:48Z 2013-10-01T00:00:00Z

Nonlinear Approaches Regarding Mechanical and Thermal Behaviour of Visco-Elastic Vibration on Isolators Năstac, Silviu Thermal effects inside the vibration elastomeric isolators have usually been neglected and this aspect can leads to certain differences between simulations and experiments. Continuous damping during the working cycle leads to an internal transfer of energy from mechanical movement to virtually infinitesimal punctual heating sources distributed into the entire isolator volume. This continuous tuning between the dynamics and the damping component can lead both to a stable and to an unstable behaviour in respect with the ratio between the external excitation frequency and the system natural frequency. These phenomena can be dignified through an additional terms added to the governing equations of the vibration isolation system. This paper deals with passive vibration isolation area and presents a set of nonlinear approaches regarding the mechanical and thermal phenomenon inside the elastomeric isolators during the exploitation time. The main idea consists in the continuous functional correlations between thermal and mechanical phenomena, and their influences upon the global dynamic characteristics of vibration isolators. Parametrical expressions were assumed from real experiments, directly or by means of computational techniques. Both lumped parameters model and finite element method simulations were performed in order to validate practical models.

2013-10-01T00:00:00Z Leopa, Adrian http://arthra.ugal.ro/handle/20.500.14043/24621 2020-09-03T13:27:48Z 2013-10-01T00:00:00Z

The Dinamic Response Analysis of the Viaduct Supported on Anti Seismic Systems with Selective Links as Viscoelastic and Dry Friction Type Leopa, Adrian This paper analyzes, on the theoretical level, the dynamic response of a viaduct section, dynamically isolated by systems with a selective type of links with viscoelastic and with dry friction. Evaluation of kinematic parameters of the dynamic response was performed in theory, in hypothesis of loaded system by impulsive actions coming from a truck passing over an obstacle placed across the road surface. There have been emphasized quantitative differences which in the cinematic parameters of the deck vibration for two considered cases: the case of using only the viscoelastic insulation type systems and the case of using viscoelastic insulation type systems with dry friction.

2013-10-01T00:00:00Z Hauk, Niculai http://arthra.ugal.ro/handle/20.500.14043/24620 2020-09-03T13:27:47Z 2013-10-01T00:00:00Z

A Method to Increase the Accuracy Of the Mathematical Model Used to Hydraulically Actuated Mechanical Systems Hauk, Niculai In order to achieve mathematical models describing hydraulically driven mechanical systems are taken into account both consumer behavior and characteristics of power sources and hydraulic circuits. The variable resistance of hydraulic circuits is very difficult to describe in mathematical terms. On the one hand intervenes the complexity of geometry of hydraulic devices and on the other hand some parts change their geometry over time. This paper presents a method for evaluating the hydraulic resistance as time-varying functions, starting from the geometry changes in fluid bodies.

2013-10-01T00:00:00Z Goanță, Adrian Mihai http://arthra.ugal.ro/handle/20.500.14043/24619 2020-09-03T13:27:47Z 2013-10-01T00:00:00Z

Consideration on 2D Constrains for Drawings Made with Existing Design Software Goanță, Adrian Mihai This paper aims at present the author's personal reasons on the set of dimensional constraints existing in each design software, that are designed to achieve certain parametric sketches. In general, constrained sketches, whatever sided they receive as value-dimensional constraints; remain permanently in the same family of geometric shapes. The study was conducted on the following design software: Mechanical Desktop 6 or NX 7.5 and Solid Edge v.20.

2013-10-01T00:00:00Z