Project

Suspension and chassis play a vital role in the structural performance of an off-road vehicle. The paper focuses on Computer Aided Engineering (CAE) modeling and simulation study of an All Terrain Vehicle (ATV) structure to analyze its static and dynamic behavior. An integrated MBD-FEA approach used for analysis purpose has been presented.

In the study, a Multi Body Dynamic (MBD) model of the ATV suspension system is built using ADAMS/Car. The effect of change in suspension hardpoints on suspension characteristics has been analyzed by carrying out Design of Experiment (DOE) study using ADAMS/Insight. This is done to minimize roll, camber and kingpin angle variation during vertical wheel travel, thus increasing stability of the vehicle under rough road conditions. This helps in optimizing the front and rear suspension geometry of ATV.

The Finite Element (FE) model of ATV chassis is prepared to check its structural integrity. The input loads at body attachment points for FE model are taken from MBD suspension bench test analysis. The input loads for impact analysis are calculated analytically. Since safety of driver depends on structural strength and robustness of chassis, it is important to evaluate the design for all possible load cases (viz., bench and impact loads). Necessary countermeasures are taken in the structure based on stress response.

Finally, various tests like double lane change, constant radius cornering and sine input are performed on full vehicle MBD model to predict its handling characteristics. This includes the steady state (understeer/oversteer behavior and roll angle) and transient (vehicle response-time lag) response. Various road profiles generated virtually in ADAMS/Car are further helpful in understanding the dynamic behavior.

The process methodology depicted in this paper is useful in design and development of ATV for SAE BAJA event. It provides an important feedback regarding vehicle structure during design phase itself well before actual prototype is built.

Break Torque:

• Brake torque is the force applied at the brake wheel to stop the motion of the moving equipment.Assuming the operating conditions for the equipment are con- stant, a brake having a retarding torque equal to the full load torque of the motor to which it is applied is usually satisfactory. Braking Torque Basic Equation (Front wheels torque)
• Brake torque is a way to measure the pressure exerted on the brake shoes and/or the rotors when slowing down or stopping the rotation of the wheels. A vehicle needs brake torque to come to a stop.

BREAK INPUT = 0

THROTTLE INPUT = 0.3

Torque is the force that provides angular acceleration to a rotating body. It is the angular equivalent of linear force. When an object is rotating around its axis, there must be a force acting upon it in order to keep it rotating.

Torque is a vector quantity. It is denoted by the symbol ????. The SI unit of torque is Newton-metre.

Torque

Torque is of two types:

• Static Torque: The torque which does not produce angular acceleration is called Static Torque.
• Dynamic Torque: The torque which produces angular acceleration is called Dynamic Torque.

Torque depends upon the following factors:

• The magnitude of the force.
• Distance between the point where force is applied and the rotation axis.

CONTINEOUS VARIABLE TRANSMISSION (CVT)

Primary Pulley

secondary Pulley

variator

Belt

In speed Reduction primary pulley will mout outward and secondary pulley will move inward it seems to be speed reduction

In Over drive primary pulley will move inward and secondary pulley will move outward it seems to be overdrive

OutPut:

Tyre:

The word tire is derived from the word attire. A wheel dressed with a tire is a dressed wheel (having attire). A modern-day tire is made from natural rubber, synthetic rubber, wire, fabric along with carbon black and other chemical compounds.

If you have a street tyre at the front it won’t get the traction it needs to slow down the motorcycle, the wheel will lock up, you will loose control and come crashing down the hill. The rear tyre with the proper dirt tread pattern will simply follow the front tyre as it doesn’t have any weight pressing it down to the dirt to hold onto something.

THROTTLE INPUT

The intake-throttle brake is that the gasoline engine develops retarding power by closing the intake throttle plate which restricts the amount of intake air. Gasoline engines commonly have an intake throttle to regulate the air flow to match the fuel flow in order to achieve stoichiometric combustion.

The basis for the throttle angle position sensor is the influence of geometric size and shape on the resistance of a conductive material. To illustrate this relationship, consider the resistance of a long section of a conductor of length L with a uniform cross-sectional area A with a voltage VS applied at the ends along the long axis.

OUTPUT

KEYTAKEAWAYS

USE Simscape ans simscapedriveline to model longitudinal vehicle dynamics

incoperate the real component data

use simulation to explore and analyse various designs and parameters

use suffecient realistic data to model real world conditions