Aceasta lucrare se ocupa cu cinematica osiei la traversarea unei curbe circulare. Sunt tratate in mod particular viteza si acceleratia centrului de masa al osiei. De asemenea, sunt calculate vitezele de alunecare dintre roti si sine. Este analizat din punct de vedere cinematic regimul cvasistatic de circulatie in curba. Sunt stabilite conditiile rostogolirii pure, precum si cele ale rularii conice.
This paper deals with the kinematics of the wheelset during curve negotiation. The velocity and the acceleration of the wheelset centroid are calculated. Also, the slip velocities between the wheels and rails are determined. The steady-state behaviour is analiyed from kinematics view point. The pure rolling and conic rolling conditions are pointed out.

Kinematics of the wheelset during curve negotiation

Podurile reprezinta structuri vitale menite sa asigure legaturile cailor rutiere si feroviare peste obstacole naturale sau artificiale. Din acest considerent, aceste structuri trebuie protejate atat impotriva actiunilor provenite din activitati seismice, cat si impotriva solicitarilor provenite din traficul rutier si feroviar. Pentru a preveni distrugerea partiala sau totala a podurilor si viaductelor supuse solicitarilor sus amintite, este necesar ca in structura acestora sa fie inglobate sisteme menite sa diminueze sau sa elimine total efectele nedorite induse de perturbatii. Un exemplu de astfel de sisteme, care sunt utilizate in cadrul podurilor si viaductelor, in vederea izolarii si disiparii energiei introduse in structura il reprezinta elementele din cauciuc laminat.
Bridges are vital structures designed to provide road and rail links over natural or artificial obstacles. For this reason, these structures must be protected both against actions coming from seismic activity, as well as against the loadings arising from road and rail traffic. In order to prevent partial or total destruction of bridges and viaducts under the above mentioned loadings, it is necessary to embed certain systems in their structure, designed to reduce or eliminate all undesirable effects induced by perturbations. An example of such systems, which are used in bridges and viaducts in the isolation and energy dissipation introduced in the structure, may be the elements of molding rubber.

Diagnosis of the dynamic isolation systems by neoprene used on viaducts, based on nonlinear vibration technique

Vibratiile actioneaza asupra corpului omenesc prin intermediul suprafetelor de contact dintre om si sistemul vibrant. Aceasta lucrare se refera la analiza influentei frecventei (4, 8, 16, 32 si 64Hz) asupra corpului omenesc, pentru timpul de vibratie de 5min. S-a obtinut o modelare a ar.m.s. pentru diferite parti ale corpului (degete, antebrat, brat, umar, git, cap). S-a observat ca valorile maxime ale acceleratiei au fost obtinute pentru frecventa de 4Hz pentru toate partile corpului pe care au fost plasate accelerometrele. Cea mai mare valoare a acceleratiei este de 2,3m/s2, la umar, pentru ν=4Hz. Acest rezultat indica faptul ca frecventa de 4Hz este frecventa de rezonanta pentru organismul uman.
Vibrations act on the human body through the contact surfaces between man and the vibrant system. This paper applies to the analysis of the frequency influence (4, 8, 16, 32 and 64Hz) on the human body during a vibration time of 5min. It was obtained an ar.m.s modelling for different body parts (fingers, forearm, arm, shoulder, neck, and head). It was noticed that the maximum acceleration values were obtained for the frequency of 4Hz for all body parts on which were placed accelerometers. The highest value of acceleration is 2.3m/s2, at the shoulder, for ν=4Hz. This result indicates that for the human body the resonance frequency is 4Hz.

Modelling of the mechanical vibrations transmitted to the human body

Sunt studiate proprietatile mecanice corespunzatoare aliajului rezistent la cald INCONEL 718
The INCONEL 718 heat resistant alloy mechanical properties are studied

Mechanical strength properties investigated on some heat resistant alloys (INCONEL X – 718)

In aceasta lucrare autorul prezinta o metoda de calcul a procesului de cuplare mecanica intre sistemul de actionare si masina de lucru (capul taietor) al instalatiilor de forat galerii orizontale in sectiune plina cu diametrul de 3,2 m. Aceasta metodologie poate fi extinsa la intreaga gama de instalatii de forat galerii orizontale (2,5-6,5)m ce a fost proiectata in Romania. Lucrarea se refera numai la rezolvarea ecuatiilor de miscare printr-o aplicatie consistenta fara a prezenta si calculul laborios al momentelor de inertie masice.
This paper presents a calculating method for the coupling process between the driving system and the work machine (cutter head) of drilling unit for horizontal galleries in full section with a diameter of 3.2 m. This methodology can be extended to the full range of drilling equipment for horizontal galleries (from 2.5 to 6.5) m which has been designed in Romania. The paper is focused only on the solutions of the motion equations through a consistent aplication without presenting the laare prborious calculation of inertial mass moments.

The study of transitory processes to start the drilling units for horizontal galleries

Articolul prezinta utilizarea unui nou instrument: modelul pompei cu jet din programul Matlab R 2011, in cadrul unei lucrari de laborator. Se realizeaza modelul echivalent al unui stand experimental existent in laborator si sunt evidentiate avantajele si limitele de utilizare ale acestui tip de model in activitatea didactica.
The paper presents the using of jet pump model, a new instrument in Matlab R 2011 program, in a laboratory application. It is build the equivalent model of an existing experimental laboratory stand and they are highlighted the advantages and limits of using of this type of teaching model.

The use of numerical simulation in the work of laboratory

Lucrarea se ocupa cu studiul vibratiilor unui tandem de roti care se deplaseaza pe o sina in prezenta neregularitatilor suprafetelor de rulare pentru a analiza cuplajul elastic datorita undelor de incovoiere care se propaga prin sina. Pentru aceasta, este utilizat modelul sinei pe suport continuu cu doua etaje elastice, iar rotile sunt modelate prin corpuri rigide. Este determinat raspunsul in frecventa al rotilor cu ajutorul modelului deplasarii rugozitatilor si sunt studiate componentele de cuplaj dintre acestea.
The paper deals with the study of the vibration of a wheels tandem moving along a rail in the presence of the rolling surfaces irregularities in order to analyse the elastic coupling between the wheels due to the bending waves of the rail. To this end, the continuous supported rail model with two elastic layers is used, and the wheels are modeled as rigid bodies. The frequency-domain response of the wheels is obtained by means of the moving roughenss model and the coupling components are analysed.

Tandem of wheels/rail vibration