Chain , Gear and Belt Drive Analysis
Gear, Chain and Belt Drive Dynamics
GT-SUITE offers modeling tools for both rapid and detailed modeling of drive systems for valvetrain timing and other engine accessories. The dynamic behavior of such systems often interacts with the dynamics of coupled engine systems and thus they are often taken into consideration and subjected to design analysis. Simulation of drive systems allows users to address key design and durability issues, while maintaining their performance, for example acceptable dynamic transmission error for valvetrain drives. A specialized GT-SUITE toolbox is aimed at the following types of drive systems:
- Gear drives and gear trains (spur or helical)
- Chain drives and chain drive systems (roller or silent chain, sprockets)
- Belt drive systems (auxiliary or timing belt, pulleys)
- Guides and tensioners for chain drives
- and combinations of the above
In GT-SUITE models of above systems are also commonly integrated with Valvetrain or Cranktrain models to represent dynamic interactions between these subsystems. In cases with hydraulic tensioning devices, parts or all of the Lubrication system supplying the oil can be simulated simultaneously.
In GT-SUITE drive systems systems are dynamically modeled using the underlying multi-body dynamics libraries. Sprockets, gears and pulleys are rotating planar (2D) inertias can be constrained by a revolute joint or journal bearing, or supported by a known (structural) stiffness and damping. Extensive outputs include all states (time plots or animations), all support (hub) loads, contact and friction forces, dynamic transmission error and chain/belt tension. Simulations are fully transient and can model, for example, speed "run-up"s often used during testing of such systems.
Both spur and helical gear can be modeled. The gear contact model fully takes into account the detailed kinematics of the contact of gear tooth involutes, and transmits torque in the geartrain through assembly of contact forces at individual tooth contacts. This allows correct representation of the change in effective stiffness within the tooth meshing cycle and the non-linear behavior and hysteresis associated with resonance of mesh frequency with system natural frequency. A simplified option is also offered, which calculates the stiffness variation through static pre-processing, and thereafter imposes it for dynamic analysis. It significantly reduces CPU time (by about 90%) but still captures virtually all of the physics.
For roller or silent drive chains every link in the chain is modeled as a planar inertia with translations and rotation. Links are interconnected with stiffness and damping representing structural stiffness, bushing clearance if applicable and oil damping. Chain link- sprocket contact kinematics are fully accounted for and torque is transmitted between sprockets through assembly of individual chain-link sprocket contact forces. Guides of various geometries (flat, arcs or combinations) can be included in a model, as well as mechanical (spring-loaded) or hydraulic tensioners, which can be of the guided or pivoted type. Two-sided silent chains which can wrap sprockets both clockwise and counterclockwise can also be modeled.
Timing and Auxiliary Belt drives are modeled by discretization into planar cable or beam finite elements, which allow representation of belt inertia, and axial stiffness (also bending and shear stiffness for the beam-element option), as well as transverse motions of the belt. Torque and forces on pulleys transmitted through assembly of dynamic or static friction forces as well as belt-pulley (normal) contact force between individual belt element and the pulley. For auxiliary (friction, V-) belts, a friction model based on "bristle stiffness" ensures that dynamic as well as static friction and locking can be modeled, without "fighting" between multiple belt-pulley contacts. Two-sided timing belts can also be modeled.
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| Gamma Technologies, Inc. 601 Oakmont Lane, Suite 220 Westmont, IL 60559 USA |
Tel. Fax. (630) 325-5849 Email: CAE@gtisoft.com Web: www.gtisoft.com |
APPLICATIONS
Engine Performance
Test Pressure Analysis
Exhaust Aftertreatment
Acoustics
SiL, HiL, real-time
Vehicle, driveline
Hybrid Vehicles
Cooling Systems
AC and Rankine
Lubrication and bearings
Fuel Injection
Valvetrain, camshaft
Cranktrain, crankshaft
Chain, gear, belt drive