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In design of valve train systems, it is useful to predict the dynamic behavior to calculate the loads, stresses and contact losses prevention. In this paper a kinematic model was developed over the cam discrete data, building a piecewise cam curve known as Spline, from the continuous curve is possible to predict the valve train kinematic characteristics, evaluating the values of displacement, velocity and acceleration of all valve train components. Based on the kinematic model results, the values of displacement imposed by the cam rotation are applied as input data to the dynamic model, that from a multiple mass system considering stiffness and damping of the components allows to know the valve train vibration behavior calculating the loads, stresses and losses of contact.

This work studies the dynamical behavior of a belt-tensioner pulley, constructed with a nonlinear spring and submitted to dry-friction on the contact of the pin with an articulated arm. Friction models are addressed, and the Duffing's equation is used to model the spring's nonlinear behavior. A mathematical model of the belt-tensioner is presented, and the influences of friction and pre-load moment are numerically investigated. The Stick-Slip behavior of the system is also studied. It is seem that the varying normal load, the friction asymmetry and the pre-load moment can change the Stick-Slip behavior. Finally, a method is presented to map the dynamical behavior of the belt-tensioner

This work develops the kinematic and dynamic analysis of a diesel engine mounted on cushions, obtaining the nonlinear equations of motion and its integration has the vibration responses of the engine. With the system response values, are simulated different position settings and characteristics of the cushions for the qualitative and quantitative evaluation of the dynamic changes occurring in the system.

In the field of engineering, there is a well known phenomenon called “stick-slip” a specific type of vibration in a mechanical system where friction is involved, it is qualified as non-linear, auto-excited and generally stable within a limited cycle. During stick-slip, the behavior of the friction coefficient as a function of the sliding velocity has big influence on the wave pattern, wherein various models can be found in the literature. Besides affecting wave patterns, this behavior affects significantly the amount of damping necessary to reach an asymptotic level of stability. The objective of this work is to study various friction models found in literature, for example: constant transition between coefficients, linear and exponential and apply these models in mechanical systems that represent brake systems.

More and more, the automotive vehicle consumers tend to opt for internal combustion engines which use chain in their timing system, since the chain drive system presents high durability, avoiding the usual maintenance common to the belt timing system. The necessity of developing parts which increase the fuel consumption efficiency and minimize noise and vibration leads to the study and comprehension of some physical phenomena such as “polygonal action” and the ability of predicting the fluctuation of angular velocity of the sprockets used for timing the crankshaft and camshaft. The study of mathematic models in parallel to the physical test guides the development of the present work.

Over the years, internal combustion engines have been researched and improved in the search for more power and for lower fuel consumption. An automotive subsystem that directly affects the performance of the engine is the valve train system. This system allows for the control of the admittance and release of gases from the combustion chamber. This system operates in all phases, ensuring that the valves open and close properly and ensuring the sealing of the cylinder. Several researchers have studied the kinematics and dynamics of the valve actuation system to improve engine performance. As the actuation of the valves occurs usually by cams, every movement and timing of the system is dictated by the design characteristics of the profile of the cams: it has a predominant action on the dynamics of the system.

Several studies on acoustics and vibration have been encouraged due to the automotive industry's interest in projecting less noisy braking systems. In the interest of furthering these kinds of studies, understanding one of the main vibration excitation phenomena in friction systems, the stick-slip, is very important. Stick-slip is an auto-excited vibration that might occur in a fixed body that frictions with another moving body, based on the difference between the static and kinetic friction force. For this reason, characterizing the friction material regarding the static and kinetic coefficients seems to be essential for developing simulations and experiments. On the other hand, the characterization of the static coefficient is very complex due to its dependence on time while the surfaces were in stationary contact.

This research presents a load cell project applied to vehicle suspension, which is an integral part of an Automatic Weighing Device (AWD). The project of the load cell was conceived based on the bending theory of circular plates, symmetrically loaded in relation to the center. Consequently maximum tension force, in the center of the plate, and its main directions were obtained. These equations were used to calculate the geometry of the load cell. An initial project of the load cell was carried out without the effect of the spherical dent from the area where the force was applied. This was done using theoretical concepts and comparing the results with those obtained by ANSYS program. The final project includes the effect of the spherical dent. The differences between the results of the experimental analysis and the numerical modeling confirm the correct choice of load cell geometry.