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The research is carried out to improve passenger’s comfort to increase the vehicles stability in dynamic conditions. The literature available in the automotive engineering considers different topics for studying suspensions. An example represents mechanisms structure and analysis (synthesis, kinematics, and dynamics) under various operating conditions. These aspects have been approached before analytically, numerical. The current paper studies the influence of the lateral force on the contact patch of the wheel and the corresponding variations of vehicle stability parameters, such as camber angle and wheel rear track. The study is performed for a newer innovative rear suspensions mechanism which does not have a wheel track and camber angle variation, relative to the chassis, when the suspension components was considered rigid. A numerical solution is obtained through a virtual model on several commercial codes: MSC Adams, Patran, Nastran. Concerning the analysed parametes, their variation increases as the applied force is increased. Moreover, the largest variation corresponds to the case were elastic bushings and deformable links are considered.

The purpose of this paper is to propose a useful method to implement active magnetic bearings (AMBs) on an existing rotating shaft which rotates on conventional bearings. This is feasible if AMBs can produce the same reaction loads of conventional ones and if the size of vane is large enough to host an AMB. As this substitution could offer some difficulties due to the different size between magnetic bearings and conventional ones, a set of equations are performed to show that a variation of some parameters can solve this problem. The journal ratio is the geometrical parameter introduced to develop the present analysis. The variation of journal ratio does not produce a variation of the pole’s surface so that the reaction load does not change. The results are analyzed by numerical analysis by mathematical relationships involving the design parameters, magneto-static simulations and dynamic simulation on shaft when it is tested by disturbance rejection and reference tracking input in order to analyze the differences on dynamic behavior of the shaft on its suspended sections. Results show that the displacement pattern of the suspended sections remains unchanged, confirming that the reaction load, produced by pole expansion, remains the same varying the journal ratio.

In this paper the results of experimental tests are shown, lead by extended method of measurement, on a tire for an off-road vehicle 175/82 R16, inserting Prescale paper at the contact with the ground. The experimental analysis of the pressures is lead, in cross-sectional direction, in 5 zones correspondents to the middle of the single dowels constituting the tread. The results are analyzed by means of software predisposed to the scope so as to go back easily to the value of the pressure. The obtained results are critically analyzed and the result are compared with those obtained by the formulas of Rowland and MacLaurin, and by the nominal pressure at ground, concluding that the expression of MMP for vehicles on wheels is simply to consider a pointer of the performances, in comparison with other vehicles or wheels, rather than a real prediction of the pressure on the ground. Besides a good agreement is found between the tire deflection calculated and measured experimentally.

The complex and highly non-linear phenomena involved during braking are primarily caused by friction materials’ characteristics. The final friction materials' characteristics are determined by their compositions, manufacturing, and the brake's operating conditions. Analytical models of friction materials' behaviour are difficult, even impossible, to obtain for the case of different brakes' operating conditions. That is why, in this paper, all relevant influences on the friction materials' cold performance have been integrated by means of artificial neural networks. The influences of 26 input parameters, defined by the friction materials' composition (18 ingredients), manufacturing (five parameters), and brake's operating conditions (three parameters), have been modelled versus changes of the brake factor C. Based on training and testing of 18 different architectures of neural networks with five learning algorithms, a total of 90 neural models have been investigated. The neural model (BR26841) trained by the two-layered neural network, with a Bayesian regulation algorithm, was found to reach the best prediction results. This neural model was able to generalize the friction materials' cold performance, for temperatures in the contact of the friction pair T>100°C, in the range of application pressure changes between 20 and 100bar, and for initial speed changes between 20 and 100km/h.

This chapter deals with the forecasting of vehicle performance on the road, according to the installed engine. It begins with Section 1, which shows the calculation of the resistance to motion, that is, the forces that the vehicle must overcome to advance on flat roads and uphill. The calculation excludes accidental resistance in curves because it is not essential for predicting the behavior of the vehicle on the road. Section 2 begins with the power characteristic, the forecast by traction–speed and power–speed diagrams, calculation of gear ratios, and then passing to the limits to the estimated acceleration, feature consumption, and distance. This chapter concludes with a section on the drivability of the vehicle, and sets out the advantages of four-wheel-drive vehicles. Keywords: motion resistances; inertia coefficient; performance forecast; power characteristic; torque characteristic; traction–speed diagram; power–speed diagram; consumption diagram; maneuverability; handling

ABAQUS gasket elements are an efficient and flexible tool to study gasket applications. Nevertheless the usage of the ABAQUS gasket elements is not limited to gasket analysis, but it provides an effective improvement in structural analysis. The results point out that both the predicted contact pressure and the predicted stress distribution depend on the mesh topology. Several combinations of mesh dimension and topology are investigated. The purpose is the definition of a calculation methodology and the demonstration of the application potentiality. Complex models analysis highlights that the set methodology constitutes a very effective tool for the design and optimization of gasket, cylinder head and cylinder block. At last a particular case is studied and a structural improvement to resolve the problem of the low seal was obtained by FEM; the modifications were introduced in the layout and the test on the modified component confirmed the calculation previsions. The qualitative and quantitative indications provided by the calculation are confirmed by the experimental results, whether in condition of cold assembly (color film paper approach) or in condition of hot working (test to motor bench).

Thermo mechanical fatigue problem is treated to define an analysis methodology permitting the strength evaluation by reliability viewpoint. The main difficulty is the lack of both theoretical and experimental information; consequently the problem is treated verifying continually the validity and the limits of the developing solution method. The main task of the activity described in this paper was the development of a numerical methodology, based on FE analyses, for the evaluation of the structural behavior of engine components subjected to thermo mechanical fatigue phenomena. The chosen application was the exhaust manifold of an IC engine; FE analyses were executed following the standard methodology consolidated by this time in CRF. In particular a time transient thermal analysis was performed taking into account the exhaust gas fluid dynamics inside the manifold; the thermo structural analysis took into account both geometrical and material non linearities; the contact between the manifold and the cylinder head was simulated and the bolts pre load was applied. The methodology can be reassumed in the following fundamental points: 1. FE modeling of the component 2. Material modeling The evaluation of the thermal fatigue damage is executed 3. Thermal, thermo structural analyses (stress, strain) adapting methods developed to face isothermal fatigue, analysing also energetic criteria. A preliminary reliability evaluation was executed, on the base of numerical results and of experimental information. The results permitted the individuation of critical areas of the manifold and a preliminary evaluation of the number of cycles allowable before the rupture. Since the several criteria furnished different durations, a more accurate evaluation may be deferred to the execution of experimental tests.