Introduction to Vehicle Dynamics ­- Measuring the Safety Factor of a Vehicle


Launching a new vehicle is always about many considerations, of which safety certainly tops the list. There are several factors that determine safety, and for brands, knowing the basics always helps. Automotive dynamics is the study of vehicles in motion and how they behave when in motion. There are companies that deal in vehicle safety testing and failure analysis of a vehicle.

Components of each vehicle module:

  • Power module: Engine, gear box and drive axles
  • Chassis module: Steering, breaks, suspension, tires, wheels and brakes
  • Body module: Bonnet, roof, door and trims.

Function of a vehicle:

The prime purpose of vehicles isn’t just about transporting people from one place to another. It is about carrying people in a comfortable, economical and safe way. The vehicle must listen to the inputs of a drive (turning/ applying breaks) and act according to the inputs. Vehicle dynamics is about studying and verifying if the vehicle responds safely to passengers.

Vehicle dynamics:

Vehicle dynamics is about a vehicle’s longitudinal dynamics aspects which are acceleration and braking. When a vehicle moves, it ideally accelerates and decelerates. When we are speeding up the vehicle, there is acceleration and when we apply brakes, there is deceleration.

There are many forces acting on vehicle when it is in motion. When a vehicle is in motion, a force acts along the forward direction and a backward force such as air resistance and friction force acts in the backward direction.

The three cases are:

  • When a vehicle speeds up: The forward force is greater than the backward force
  • When a vehicle is in constant acceleration: Forward and backward forces are in acceleration
  • When a vehicle speeds down: The backward force is greater than forward force

When the driver hits the brakes (input), the vehicle slows down (output) and due to this the passengers will be pushed forward due to the vehicle coming to a halt. To make sure a vehicle is safe and comfortable, the input and corresponding output response are measured using mathematical modeling techniques.

The application of mathematical techniques is helpful in looking at the vehicle’s responses in various perspectives.

The study involves checking for:

  • Longitudinal dynamics: Involves assessing the behavior of a vehicle when it moves in a straight line
  • Lateral dynamics: Involves assessing the behavior of a vehicle when it takes a turn
  • Vertical dynamics: Involves assessing the behavior of a vehicle when it moves in the vertical direction like speed breaker or puddle.

A vehicle’s dynamic behavior can be studied in many ways. Analysis of all the different forces helps one understand vehicle dynamics better.