Applied Mechanics and Materials Vol. 822

Abstract: In this paper, it is deduced the ordinary differential equation that results in angle variation between the vehicle mass centre rate and the vehicle fore-aft axis. There are presented the wheels turning angles variations dependent on the angle that gives the vehicle orientation on trajectory. There are studied the following cases: the transfer from linear to circular motion, the transfer from circular to linear motion and the movement amidst poles. For each of these motions, there are presented the vehicle orientation angle variations on trajectory for three distinct rates. It is also presented the travelling rate influence on how the vehicle is situated on trajectory.

Abstract: The paper presents a short systematization of the Theory of Sonics in a synthetic manner. Beginning with the definitions of sonic resistances, one can obtain practical computing formulas for various types of simple resistances and impedances or some of their connections. The resulting data is shown in tables which contain practical calculation formulae, useful in teaching activities and scientific researches.

Abstract: The paper presents a modal analysis for the helicoidally spring from the compound of the Macpherson automotive suspension. In the first part, it is described the device used for the experimental study and then, the measurement equipment used, too. First of all, it is represented the kinematical scheme and 3D representation for the device mechanism included the helicoidally spring necessary to the dynamic analysis. After this, are made some measurements of different parameters of the helicoidally spring obtaining the experimental values which are compared finally with the simulation results.

Abstract: This article presents the results of experimental study of the influence of tire vertical load and tire internal pressure on tire cornering stiffness. The results have been obtained with a mobile tire tester which was developed at department “CEAET” at TU-SOFIA. The information about the dates of size load, index speed, index group, wearing out is obtained from Goodyear website, www.goodyear.eu. The study process concerns three main areas: (i) the choice of the experimental methodology; (ii) calculation and analysis of the data; (iii) discussion and conclusion. The obtained results give the possibility to determinate the role of tire on vehicle handling and stability.

Abstract: The paper purpose is to evaluate the efficiency of a new kind of suspension trim corrector based the tests on rigs an on the vehicle. The trim correction is realized by two pneumatic elements placed on the vehicle rear shock absorbers. The tests on rigs were realized on a hydropuls rig recording the force evolution with the stroke for some pneumatic pressure. Then the trim correctors were placed on the vehicle, being tested the trim evolution with the pneumatic pressure for some loaded states. Finally the tests were continued on road to evaluate their well behavior for some loaded vehicle states. All results confirmed the high efficiency of the new trim model and its well behavior on road. This reason the new trim corrector solution is in protection phase.

Abstract: Towbars are the main component of the assembly connection between the vehicle and the trailer. With proper use, recommended by the towbars producer, and the correct calculation and design by the manufacturer in accordance with international law, they ensure road safety.The main role of the towbars is to maintain in maximum safety conditions, the link between towing vehicle and various aggregates, namely trailers.

Abstract: This research presents the use of a computer oriented numerical approach in the characterization of a parallelogram mechanism used on automobile windscreen wipers. The aim is to perform a kinetostatic analysis for obtaining through numerical simulations the joint reaction forces for a parameterized mechanism. Based on a combination between classical methods and computer simulations using Multi-body System method, the friction forces between wipers blades and windshield will be evaluated. The obtained results add new contributions on automobile windshield wiper mechanism design and analysis.

Abstract: Raising the thermal comfort inside the car is a primary task of the car manufacturers and therefore the process of designing an optimal solution to improve the parameters of the thermal comfort is considered to have a tremendous importance. Considering this, in this paper we aim to adapt within the car a system of air conditioning which is used in the classical way, especially in the civil engineering industry. The proposed solution consists of designing a chamber used for the fluid preparation. The system includes some preset modules of the parameter values for the thermal comfort depending on climate and season, and also the possibility to customize the standard settings with the preferred ones of the vehicle occupants. This way it will be maintained a high level of thermal comfort and also the risks of accidents will be reduced (the driver can focus on the driving act instead of setting the parameters for thermal comfort). The paper also shows an experimental stand which can be used to study the thermal comfort parameters such as air temperature, humidity and air velocity and also to collect the results.

Abstract: 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.

Abstract: An exact measurement of the disc brakes car temperature present difficulties, because the higher thermal stress is produced on the shiny metallic surface, which are in movement and in sliding contact with the brake pads. If an infrared camera is used for the thermal evaluating of the disc brakes, an important factor that must be considered is the reflected temperature. The aim of this research is to study the modification of the reflected temperature in correlation with the disk brake temperature and to establish a relationship for the estimation of this variation.