Mario Trotea

Fatigue Analysis for the Primary Shaft of a Mechanical Gearbox of a Car

The paper presents the fatigue analysis of the primary shaft of a mechanical gearbox with three axles for a SUV car. For the analytical fatigue calculation the Soderberg method was used for finding the global fatigue safety factor. The numerical fatigue analysis was performed using Ansys software for the maximum load case of the primary shaft using Soderberg mean stress theory from Ansys Fatigue Tool.

Mathematic Model for Analysing the Dynamic Behavior of a Vehicle in the Field of Chaotic Movements

This paper presents a plane equivalent model of the vehicle and its mathematical model attached. The mathematical model is under a form of four differential equations system of order 1, in order to analyze the dynamic behaviour of the vehicle movement. Its goal is to determine the ranges of speed for that movement is stable or is unstable, or having chaotic character. The authors consider being necessary to know the conditions in which movements occur chaotic movements to avoid them through constructive or functional limitations. Speed values are identified for the behaviour of the system is placed in the quasiperiodic movements field or exceeding these movements trough chaos and are highlighted by the specific instruments: the trajectories in the phase plane, Poincare section and power spectra.

Analysis of the Commercial Speed of a Public Passenger Transport Line from Craiova-Romania

This paper presents the analysis and the way of determining the commercial speed for a public transport route (a line) of people from Craiova. Calculate the optimal distance between the stations on the route under consideration, which will ensure a minimum journey time for the passengers. Commercial speed was determined according to the length of the route and its time, which depends on the number of stations, the passenger flow and traffic conditions specific to Craiova.

Influence of Carburizing Time of Iron Powder Samples on the Carbon Content after Gas-Carburizing - Sintering Process

The paper presents experimental results of the influence of carburizing time of iron powder samples on the carbon content in the sample’s depth by layers, subjected to a GCS (Gas-Carburizing Sintering) method. Sintered steel elaboration by GCS method consist of enriching the Fe powder with carbon in gas medium in a single thermal cycle including the carburising operation followed by sintering, thereby achieving the sintered carbon steel. Numerical simulations were made using Abaqus/CAE software for mass diffusion analysis in order to find the appropriate diffusion coefficient value.

Nonlinear differential system applied of a mechanical plan model of the automotives used for the nonlinear stability analysis

This paper proposes a plan mechanical model for the vehicles with two axles, taking into account the lateral deflection of the tire. For this mechanical model are determined two mathematical models under the nonlinear differential equations systems form without taking into account the action of the driver and taking into account. The analysis of driver-vehicle system consists in the mathematical description of vehicle dynamics, coupled with the possibilities and limits of the human factor. Description seeks to emphasize the significant influence of the driver in handling and stability analyzes of vehicles and vehicle-driver system stability until the advent of skidding. These mathematical models are seen as very useful tools to analyzing the vehicles stability. The paper analyzes the influence of some parameters of the vehicle on its behavior in terms of stability of dynamic systems.

THEORETICAL AND EXPERIMENTAL RESEARCH ON THE TORQUE VARIATION OF THE BODY PASSING THROUGH LANDMARKS

This paper presents analytical expressions of the vertical reactions of the car wheels. These mathematical expressions take into account the inertia forces which are expressed by two main components of acceleration of the reference system chosen. The vertical reactions of the wheels and the torque acting on the body are determined by analytical and experimental methods in case of movement among the landmarks when the vehicle speed is 25 km/h. Theoretical results are compared with data obtained from experimental tests. Approximation values of the two data sets validates the theoretical model adopted.

Experimental Determination on Behavior of Composite Laminated Body Elements at Temperature Variations

The design of layered composite body elements requires knowledge of the behavior of these materials under operating conditions of the vehicle. The experimental researches were carried out on material produced in the laboratory and have been determined the change in bending and rolling characteristics at temperatures of 80°C, -30°C and in humidity conditions. Also it was attempted to determine aspects regarding the causes and mechanism when these conditions affect the changes of the mechanical properties.

Theoretical and Experimental Researches Regarding the Influence of the Suspension Car Stiffness on the Dynamic Behavior of Vehicles

In this paper the authors present the results of theoretical and experimental research in order to optimize suspension rigidity in case of Daewoo Nubira vehicle. The paper presents the mathematical model obtained by assimilating car with a dynamic system with 5 rigid solids with elastic and viscous linking between them. Theoretical results obtained based on this model and the experimental results are presented, and it is presented a solution to optimize suspension in order to remove the negative effects observed driving on gravel runways or damaged runaways. Theoretical results, compared with the experimental ones, allow us to say that it is possible to optimize suspension by analyzing specific parameters equivalent mathematical model.

Design Optimization of the Rear Wing of a Sports Car

In this paper it is presented the design optimization of the rear wing of a sports car. The wing profile was parameterized with three variables, the angle of attack was the fourth variable and the objective function was to minimize the lift over drag ratio. Three virtual models were considered: a model without rear wing, a model with a rear wing with initial profile and position and a model with optimized rear wing. For these three models the drag and lift coefficients were calculated for comparison along with drag and lift forces.

Design Optimization of the Diaphragm Spring of a Mechanical Clutch for Motor Cars

In this paper it is presented the design optimization of the diaphragm spring for a mechanical clutch. The slot shape of the fingers was parameterized and the objective function was the maximum tangential stress to be minimized subjected to the constraint that the deflection of the spring on exterior diameter in the spring centreline direction has a minimum certain value when the clutch is disengaged.