L. Walha

Dynamic response of a Spur gear system with uncertain friction coefficient

Abstract In this paper, we propose a method for taking into account uncertainties based on the projection on polynomial chaos. The proposed method is used to determine the dynamic response of a spur gear system with uncertainty associated to friction coefficient on the teeth contact. We developed a lumped dynamic model with 8dofs. Lagrange formalism is used to formulate the governing equation of motion of the model. The simulation results are obtained by the polynomial chaos method for dynamic analysis under uncertainty. The polynomial chaos results are compared with Monte Carlo simulations.

Vibration Analysis of a Nonlinear Drivetrain System in the Presence of Acyclism

Drivetrain vibrations are a great concern in the automotive industry, once they are related to many Noise, Vibration and Harshness (NVH) phenomena. An automobile drivetrain system generally consists of the following main components: engine, clutch, gearbox, disk brake, and transmission shafts. This paper represents a nonlinear dynamic model for each drivetrain components in the presence of the acyclism phenomena (cyclostationary regim). This model is simulated by 18 degrees of freedom. The governing nonlinear time-varying motion equation formulated is resolved by the analytic Runge–Kutta method. The dynamic responses of the clutch and the single-stage helical gear reducer are investigated in the idle engine regime. The results are presented in the time and time-frequency domain by using the Wigner-Ville distribution. The dynamic behavior study of the system, comes to confirm the significant influence of the engine excitation (torque and speed fluctuation), particularly in the case of the gasoline engine acyclism condition.

Modal Analysis of the Clutch Single Spur Gear Stage System with Eccentricity Defect

Gears are an important element in a variety of industrial applications. An unexpected failure of the gear may cause significant economic losses. For that reason, fault diagnosis in gears has been the subject of intensive research. Modal analysis can be used in the fault detection of rotating machinery. It can provide natural frequencies and vibration modes which are essential information to learn about most of dynamic characteristics of the combined system. In order to investigate the dynamic behavior of a coupled clutch-gear transmission system in the presence of gear defect, a general dynamic model is developed and a numerical modal analysis technique is achieved. Several types of gear defects that can be found in the literature. In this paper, a gear eccentricity defect is introduced in the model to study their influence on the modal properties. The distributions of modal kinetic and strain energies are presented in the case without and with defect on the geared system, and a comparative study is conducted.