What is Vehicle Dynamics? Learn how it is being used
Apply your expertise to real world problems if you really want to have a positive impact on the world in which you live.
EVER WONDER WHY...
- your car leans forward when you brake?
- why F1 cars have an outer angle of the wheel turned at a higher angle than the inner wheel, unlike the passenger cars?
- �it's easier to turn a trolley than a car with the same weight as a trolley?
- or how does the power get transmitted in an automobile vehicle?
Well, Vehicle Dynamics has answers to all such questions.
Vehicle Dynamics is everything that makes a car move forward and understand why it's moving forward.� It's a much deeper understanding of every single mechanical component and dissecting the parts to its very core and then analyzing the reasons behind it. The study of VD starts with the interfaces between the vehicle and its environment. The tires transfer loads that produce desired motions.
AREAS WHERE VEHICLE DYNAMICS IS APPLIED
1. Suspension system
The suspension is the system of tires, springs, shock absorber and linkages that connects a vehicle to its wheels and allows relative motion between the two. The suspension system provides not just comfortable rides but has a huge impact on the dynamic working of the vehicle. Longitudinal and lateral motions are handled by a suspension system. A skilled VD engineer needs to design the suspension system to satisfy vehicle needs. Design of Suspension system includes:-
- Suspension geometry
- Toe and slip angle
- Spring rates
- Scrub and camber
- Frequencies and damping ratios
TYPES OF SUSPENSION:-
2. Steering System
The Steering System is responsible for turning the vehicle but more importantly, it gives the driver a sense of control over the vehicle. Have you noticed the force required at the steering wheel of a hatchback is almost similar to the force required to steer a heavy vehicle such as buses and trucks? Rules to be considered while designing steering system:-
- Ensure precise turns
- Ensure directional stability of the vehicle
- Have maximum contact patch during turns
- Overcome understeer or oversteer
- The system needs to be light in weight
Design of Steering systems includes:-
- Ratio and angle
- Steering force
- Tire loading for power steering
3. Chassis Design
The chassis frame is basically a framework of the automobile and supports all the parts of the automobile attached to it. All the systems related to the automobile-like power train, transmission, steering, suspension, braking system are attached to and supported by it only. It bears all the stresses on the vehicle in both static and dynamic conditions. Chassis engineers use benchmarks to select the material and shape of the chassis. Engineer design the chassis in such a way that it not only supports the component but allow their desired motion and absorb shocks without deforming. Once the design engineer does their job to make a chassis as required, it is then analyzed for safety by a CAE engineer. This analysis reveals the weak spots in the chassis will behave when all the other subsystems are working. The chassis design includes:-
- Chassis loading conditions
- Bending and torsional rigidity
- Chassis analysis
TYPES OF CHASSIS:-
4. Tire Modeling
Tires are responsible for:-
- Bringing the steering wheel back to its original position after the turn is completed.
- Tire allows the vehicle to stay on the road even when there's a high centrifugal force pushing the vehicle out of the road while cornering.
- Providing comfort to the passenger and driver is also a task of tires by absorbing small shocks.
Considerations for selection of tires:-
- Tread shape
- Size of tire
- Tire forces and contact
- Tire contact path
- Tipping torque
- Lateral force
- Longitudinal force
VD engineers design the power train in such a way that the required torque and top speed is achieved. DOES MORE CC MEANS MORE SPEED??? NO, it means more power.� As per the application engineer decide to turn the power from engine into speed or torque. KTM Duke 390(373 CC engine) is way faster than Thunderbird Classis 500(499 CC engine). But the Thunderbird can easily take load of 300 kg of load going uphill where the Duke would struggle at loads near to 200 kg. POWER TRAIN DEPARTMENT: -
- Air system: - air intake and air exhaust
- Drive train: - differentials, axels or shafts, hubs
- Gear ratios
- Shaft design
- Power to RPM
It's a common misconception that the function of braking system is to stop the vehicle. Wherein it's to stop the vehicle in the shortest distance possible. It is a device that absorbs energy from a moving system. Engineers design the braking system considering the maximum speed of the vehicle. Because to stop any moving object we need to convert its kinetic energy into some other form of energy. Kinetic is directly proportional to the velocity squared. Why the braking front wheels are more on the front than rear wheels??? This is called brake biasing, it's an important technique to compensate the longitudinal load transfer while braking. Components of the braking system: -
- Brake pedal: - located in the center of the accelerator and clutch pedal. The system is activated only after pressing this pedal.
- Brake fluid: -� it is a type of hydraulic fluid used to transfer force into pressure.
- Fluid lines: - pipes through which the brake fluid flows to the calipers.
- Brake pads: -� they are steel�backing plates used in disk brakes.
Design of Braking system includes:-
- Braking force
- Braking distance
- Braking lining and hydraulic force
- Heat dissipation
- Caliper design and braking pads
Types of braking systems: -
LATERAL DYNAMICS It's about how steerable the vehicle is for different simplification, one can say those lateral dynamics are about how steerable the vehicle is for different given longitudinal speeds. Lateral dynamics deals with low-speed maneuverability, steady-state cornering at high speed, transient handling, and lateral control functions. ASSUMPTIONS: -
- Longitudinal velocity is constant
- Left and right axle are lumped into a single wheel (bicycle model)
- Suspension movement, road inclination, and aerodynamics influences are neglected.
LONGITUDINAL DYNAMICS Deals with propulsion and braking functions over longer events, functions in shorter events, and control function. VERTICAL DYNAMICS Vertical dynamics are important since vehicles are operated on real roads, and real roads are not perfectly smooth. Also, vehicles can be operated off-road, where the ground unevenness is even larger. Deals with suspension system, road models, ride comfort, fatigue life and road grip. This knowledge of VD is not only applied in conventional IC engine vehicles but a major part of designing autonomous vehicle and electric vehicles too. So this was a basic idea about vehicle dynamics and its importance.� If you wish to learn more about the fundamentals of vehicle dynamics and the latest trends in the field, and bridge the major gap between Academics and Industries, do consider enrolling in our course�"Vehicle Dynamics: Basics To Expert On Commercial & Race Cars".