L1 GPS as Tool for Monitoring the Dynamic Behavior of Large Bridges

Unraveling the Dynamic Behavior of Ecological Models: Algebraic, Geometric and Numerical Methods of Analysis

Comments® on Theoretical Biology ◽

10.1080/08948550213853 ◽

2002 ◽

Vol 7 (3) ◽

pp. 155-176

Author(s):

J. V. Greenman

Keyword(s):

Numerical Methods ◽

Dynamic Behavior ◽

Ecological Models ◽

Methods Of Analysis

Download Full-text

Multiscale analysis of the effect of grain size on the dynamic behavior of microalloyed steels

DYMAT 2009 - 9th International Conferences on the Mechanical and Physical Behaviour of Materials under Dynamic Loading ◽

10.1051/dymat/2009142 ◽

2009 ◽

Cited By ~ 1

Author(s):

A. K. Zurek ◽

K. Muszka ◽

J. Majta ◽

M. Wielgus

Keyword(s):

Grain Size ◽

Dynamic Behavior ◽

Multiscale Analysis ◽

Microalloyed Steels

Download Full-text

Ball bearing turbocharger vibration management: application on high speed balancer

Mechanics & Industry ◽

10.1051/meca/2020091 ◽

2020 ◽

Vol 21 (6) ◽

pp. 619

Author(s):

Kostandin Gjika ◽

Antoine Costeux ◽

Gerry LaRue ◽

John Wilson

Keyword(s):

Dynamic Behavior ◽

High Speed ◽

Internal Combustion Engines ◽

Ball Bearing ◽

Squeeze Film ◽

Design And Technology ◽

Squeeze Film Damper ◽

Damping Coefficients ◽

Bearing Loads ◽

Stiffness And Damping

Today's modern internal combustion engines are increasingly focused on downsizing, high fuel efficiency and low emissions, which requires appropriate design and technology of turbocharger bearing systems. Automotive turbochargers operate faster and with strong engine excitation; vibration management is becoming a challenge and manufacturers are increasingly focusing on the design of low vibration and high-performance balancing technology. This paper discusses the synchronous vibration management of the ball bearing cartridge turbocharger on high-speed balancer and it is a continuation of papers [1–3]. In a first step, the synchronous rotordynamics behavior is identified. A prediction code is developed to calculate the static and dynamic performance of “ball bearing cartridge-squeeze film damper”. The dynamic behavior of balls is modeled by a spring with stiffness calculated from Tedric Harris formulas and the damping is considered null. The squeeze film damper model is derived from the Osborne Reynolds equation for incompressible and synchronous fluid loading; the stiffness and damping coefficients are calculated assuming that the bearing is infinitely short, and the oil film pressure is modeled as a cavitated π film model. The stiffness and damping coefficients are integrated on a rotordynamics code and the bearing loads are calculated by converging with the bearing eccentricity ratio. In a second step, a finite element structural dynamics model is built for the system “turbocharger housing-high speed balancer fixture” and validated by experimental frequency response functions. In the last step, the rotating dynamic bearing loads on the squeeze film damper are coupled with transfer functions and the vibration on the housings is predicted. The vibration response under single and multi-plane unbalances correlates very well with test data from turbocharger unbalance masters. The prediction model allows a thorough understanding of ball bearing turbocharger vibration on a high speed balancer, thus optimizing the dynamic behavior of the “turbocharger-high speed balancer” structural system for better rotordynamics performance identification and selection of the appropriate balancing process at the development stage of the turbocharger.

Download Full-text