Accidents highlight the need for ensuring car safety, as well as the need to follow safety norms. As per WHO, road traffic injuries are the leading cause of death for children and young adults aged 5-29 years, and about 1.3 million people get fatally injured worldwide every year in road crashes. Road traffic crashes cost most countries 3% of their gross domestic product, and about 93% of the crashes occur in low- and middle-income countries, even though these countries only have approximately 60% of the world's vehicles.In fact, there’s an 85% chance of being fatally injured even in a 65km/h (40mph) car-to-car side-impact collision (not head on) based on its latest testing data. With advancing vehicle technologies and capabilities, as well as the evolution of EVs, the role of testing in vehicle development has never been more important. A crash test is a form of destructive testing that is performed in order to ensure safe design standards in crashworthiness and crash compatibility. Improving car safety means building more crashworthy vehicle structures and providing them with more effective restraint systems like seat belts. Car manufacturers now incorporate a wide range of safety devices and features into their vehicles, including airbags, seat belts, energy-absorbing steering columns, and side-door beams. Some car manufacturers are also experimenting with safety bags that open on the exterior. Crash tests are frequently used to help evaluate car safety and find out the efficacy of these experiments. Different car safety programs and organizations specify how such tests should be performed, what factors should be investigated and how car safety should be assessed. Crash tests are carried out throughout a car's development phase. It begins with the prototype and continued through the validation stage. It takes considerable resources to conduct these tests that involve skilled and trained personnel along with a large variety of sophisticated monitoring and measurement equipment and post-crash data analysis software.
Mechanism of a Car Crash Car crashes follow Newton’s three laws of motion. Put succinctly, the first law states that when the net force on a body is zero, its state of motion does not change. The second law says that the acceleration of an object depends upon its mass and the net force acting on it. The third law relates the forces that two interacting bodies exert on each other. Together, the three laws deal about inertia, force and momentum. During a car crash, kinetic energy is transferred from the vehicle to whatever it hits, be it another vehicle or a stationary object. This transfer of energy, depending on variables that alter states of motion, can cause injuries and damage cars and its occupants. The object that was struck will either absorb the energy thrust upon it or possibly transfer that energy back to the vehicle that struck it.
A basic characteristic of a vehicle structural response in crash testing and model simulation is the ‘crash signature’, commonly referred to as the crash pulse.The crash pulse is one of the most useful types of data for describing what occurs to a vehicle’s structure in a crash.The crash pulse measures energy variations during the impact and can also be used as an input to a simulation model to determine how occupants react to a crash.
There are two structure types commonly found in vehicles - unitized body and body-on-frame structures. The unitized-body vehicle has no separate frame or steel girders. It has comparatively thin pieces of body sheet metal which are stamped into complex shapes and welded together to provide the strength required for the chassis. The resultant structure is usually stiffer and lighter than one using separate frame and body construction. Unitized bodies are commonly found on small and compact vehicles. In the body-on-frame vehicle, the body or cab is fastened to the frame by body mounts. Body mounts are designed to carry the horizontal impact load in an accident and to isolate the noise, vibration, and harshness due to road surface excitation from entering the passenger compartment. The crash pulse, which describes the nature and severity of a vehicle crash, depends not only on the type of structure, but also on the measurement site and the impact mode.
Car Crash Simulation Software Would you crash drive a prototype car into a wall to test it for safety? Neither would anyone else. That is why car crashes are simulated by the use of human like dummies. Although full-scale crash tests can accurately replicate actual accidents, they are complex and expensive. In a crash test, sensing devices and crash test dummies are mounted in the car to measure the displacement, velocity, and acceleration at different points on the dummy or on the car structure. The data from such tests are widely used to assess vehicle crashworthiness and occupant safety.Nowadays, due to advanced research in computer simulation software, simulated crash tests can be performed beforehand the full-scale crash test. Therefore, cost associated with real crash test can be reduced.
As awareness of car safety spreads, automobile companies will be required to come up with safer cars that offer advanced safety features. Since vehicle crash tests are complex and complicated experiments, involving dummy positioning, seat belt routing, and seat deforming airbag folding, including reference geometry generation, mesh quality module and many other parameters, it is advisable to simulate the crash with a mathematical model rather than with a prototype every time. HyperCrash™ and Radioss™ from Altair are a few examples of software that covers all aspects of crash testing that are popular with the car manufacturers for the features and reliability they offer.
Vehicle Safety Norms in India
In 2014, the government of India launched a Statutory Car Assessment Program. However, there were no standards fixed for front and side impacts, and it got sidelined. In January 2022, the government issued a notification for new safety norms so that the safety norms in India would be at par with the rest of the world. Called as the Bharat New Vehicle Safety Assessment Programme (BNVSAP), it is an assessment programme for safety rating of new vehicle models sold or being sold in India. The Bharat NCAP specifies following list of crash tests to be performed on a new car before it is being rated:
The objective of these tests is to provide consumers in India an indication of the level of protection offered to the occupant/s by evaluating the safety of a vehicle for adult and child occupants, as well as for the safety assist technologies the vehicle provides. A few parameters for safety assist technologies include intelligent speed assistance, advanced emergency braking, and lane-keeping technology.
As average car speeds increase and the sheer number of vehicles plying on the road increase, car manufacturers in India will have to be vigilant and proactive in protecting passengers from mishaps. Choosing the right car crash simulation software is the first step in increased car safety.