"Behavior." . . "Gears." . . "Machinery and tools." . . "Rotors." . . "Finite element method." . . "Vibration." . . "NATIONAL AERONAUTICS AND SPACE ADMINISTRATION CLEVELAND OH LEWIS RESEARCH CENTER." . . "Bearings." . . "Transmissions (Machine elements)" . . "Gear noise." . . "Dynamics." . . "Transmission gears." . . . . "Mechanics." . . . . "This paper presents an analytical simulation of the dynamics of a gear transmission system compared to experimental results from a gear noise test rig at the NASA Lewis Research Center. The analytical procedure developed couples the dynamic behaviors of the rotor-bearing-gear system with the response of the gearbox structure. The modal synthesis method is used in solving the overall dynamics of the system. Locally each rotor-gear stage is modeled as an individual rotor-bearing system using the matrix transfer technique. The dynamics of each individual rotor are coupled with other rotor stages through the nonlinear gear mesh forces and with the gearbox structure through bearing support systems. The modal characteristics of the gearbox structure are evaluated using the finite element procedure. A variable time stepping integration scheme is used to calculate the overall time transient behavior of the system in modal coordinates. The global dynamic behavior of the system is expressed in a generalized coordinate system. Transient and steady state vibrations of the gearbox system are presented int he time and frequency domains. The vibration characteristics of a simple single mesh gear noise test rig is modeled. The numerical simulations are compared to experimental data measured under typical operation conditions. The comparison of system natural frequencies, peak vibration amplitudes, and gear mesh frequencies are generally in good agreement."@en . . . . . . . . . . . . . . "Analytical and Experimental Study of Vibrations in a Gear Transmission"@en . . . . "Analytical and experimental study of vibrations in a gear transmission"@en . . . . . . . . . . "Numerical analysis." . .