[YesAuto Safety Technology] The 150-meter length is used to create the world record battlefield of 14 seconds and 35 for Usain Bolt; the 150-meter depth is the limit of water resistance for some watches; The height of 150 meters is the bungee jumping height of Margit Thor, a 95-year-old Finnish grandmother. Just 150 meters can create countless miracles and countless stories.
In the IIHS collision laboratory near the US capital Washington, the vehicle passed a 150-meter-long towing track, and what awaited it was a solid barrier. The 25% offset collision experiments did not know that many mature models were broken. . However, their “sacrifice” is not without doubt. In this time of experimentation, vehicle safety development is undergoing a leap from quantitative change to qualitative change. This time, we will visit the scene in person to reveal stories that are not visible in the experimental report.
In this era of information explosion, even if you have not deliberately paid attention to these collision laboratories, you must be familiar with one or more of the names of C-NCAP, E-NCAP, J-NCAP, NHTSA, and IIHS. Although the countries are different, they have one thing in common that is that they are all studying what happens at the moment of a vehicle collision.
In 2012, the name IIHS began to attract our attention. The reason is very simple. Some medium-sized cars that we are familiar with and have achieved good results in many crash tests only got passing scores in its 25% offset crash test. I think only by going to the United States in person can the answer be revealed.
● “Support” behind IIHS
Different from other crash testing institutions, their project settings are all collected from data collected from actual crash accidents. In other words, it will regularly collect the accidents with the highest probability of occurrence and the highest probability of casualties on the roads in the United States, and set up experimental projects based on this. To put it plainly, its experimental projects are set up more grounded and closer to the accidents we may encounter in ordinary times.
In the final analysis, IIHS is actually using the funds of insurance companies to conduct tests to promote car companies to improve vehicle safety and ultimately reduce insurance company premiums. This virtuous cycle ensures that IIHS can continue the experiment. And such research is constantly improving vehicle safety, and consumers are also willing to pay attention to and believe in such experiments.
■ 25% offset collision test
In 2012, IIHS analyzed from the collected information that although collision experiments have been conducted for many years, the number of deaths due to frontal vehicle collisions in the United States has not dropped significantly each year. After investigation, a considerable part of the accidents were caused by collisions between vehicles and vehicles in a small area. For this reason, IIHS pioneered the addition of a more stringent small overlap area, that is, a 25% offset collision test.
For the 25% offset collision experiment, we have conducted an analysis that lasted for 3 years. In each report, IIHS will evaluate the body structure of the vehicle under test, the hidden danger of dummy injury, and the restraint ability of the safety system. When we came to the laboratory this time, we naturally cared more about the story behind the experiment.
● One minute on stage, ten years off stage
Like many artists who need to make unimaginable efforts for the blooming on stage and offstage, the pre-preparation for an experiment with an impact lasting less than one second is a rigorous and complicated process. However, these things that are usually not visible in the experiment report are the important purpose of our trip.
After the oil is replaced and the body size measurement is completed, the engineer will cut off the brake bus and transfer the brake control to the controllable unit arranged in the trunk. In addition, in order to more accurately control the impact speed of the vehicle, engineers will also weld a towing hook to the chassis, so that the hydraulic traction device can be used to accurately push it to the experimental speed.
Before the preparation work comes to an end, the engineer will again pre-adjust the final impact position of the vehicle and the barrier. The purpose of this is to ensure that the vehicle can hit the designated position according to the established trajectory, and to pre-adjust various cameras to ensure The moment of the vehicle collision is recorded completely and without blind spots.
● A successful collision is just the beginning
In recent years, carbon fiber materials, all-aluminum body, laser welding and other materials and technologies have begun to be applied to mass-produced cars. Will these new technologies affect the results of collisions? Russ and his colleagues don't seem to be “very concerned”. In their minds, whether it is to use new materials or apply new structures, the goal of these measures is to improve vehicle safety and achieve the same goal by different routes. This kind of open-ended thinking that only looks at the results, regardless of the process, really has a little taste of American education.
Since we are going to carry out the collision test of the new model that the manufacturer has not announced, we can only leave the 25% collision test track reluctantly. However, Russ said with a childish expression that he would “use his authority” to compensate us, and then he took us to a corner of the laboratory, and we really made a new discovery.
The real world is cruel. Although R&D personnel spend a lot of time in the laboratory for safety structure development, accidents such as wrong overtaking routes often crash in places that R&D personnel do not expect. In other words, in real accidents, collisions do not always occur on the driver's seat side.
For designers of body structure and crash safety, the 25% offset crash test puts them in a greater test. The smaller the contact area between the vehicle and the barrier means that the space left for the vehicle to buffer and absorb energy is smaller, and the impact point of such a collision will basically avoid the longitudinal beam used to absorb the energy collapse, and the energy during the collision It is almost unobstructed and directly transmitted to the crew cabin. During this process, the front suspension, front wheels, and steering mechanism of the vehicle will also be displaced backwards, and in severe cases may intrude into the passenger compartment and cause injury to passengers.
The impact position is changed from the driver's seat to the passenger seat, which means that the dummy will no longer be unable to make full contact with the airbag due to the deviation of the steering column, nor will the foot be injured by the pedal. The collision test is increased from the driver's seat side to the passenger seat side. This change will play a new role in the development of vehicle safety structure.
■ Do not experiment for experimentation
The 25% offset collision experiment is just the most representative of the many experiments conducted by IIHS. Russ was very generous to satisfy our curiosity and took us to visit other projects. From these experimental projects and model performance, we have also seen a step-by-step improvement in vehicle safety performance.
In half a century, the regulations for vehicle crash tests have become more and more stringent, and at the same time, the number of test items has gradually increased. From the simple frontal collision at the beginning, to the side collision, rollover test, and even the active braking test, in this showroom of IIHS, we have seen the evolution of collision experiments approaching and simulating real-world accidents. In this process, vehicle safety is also improving step by step.
However, even if the vehicle safety structure is further developed, if the collision speed is too fast, the survival probability of the occupants in the vehicle will still be significantly affected. This is not a loophole in the development of vehicle safety. Therefore, for the recent collision in Nanjing, Russ said that the relatively small model is a bit disadvantageous. What's more, the side of the Mazda 2 body that received the impact of the BMW 7 Series front head was the side of the Mazda 2. This collapsed, small energy-absorbing area and relatively weak resistance to collisions suffered from energy in this impact that has far exceeded the design limit.
In passive safety, or in collision experiments, IIHS is indeed ahead, but E-NCAP has incorporated vehicle active safety, that is, active braking system testing, into the evaluation system. So, how will the IIHS, which has always been unwilling, react? Russ did not answer this question head-on, but took us outside the laboratory.
At the end of the interview, I asked Russ curiously, what moments he felt most proud of in their work or the many tests in the collision laboratory. He thought for a moment and took us to the entrance of the collision center. Following the direction of his fingers, we saw the answers given by security developers of different ages.
Full text summary:
The attributes of a non-profit organization and an independent identity allow IIHS to exist objectively and impartially in an environment involving multiple interests. Use the funds provided by the insurance industry to support the experiment to promote car companies to improve vehicle safety and ultimately reduce insurance company insurance premiums. This kind of circular capital circulation method ensures that IIHS can continue the experiment and promotes vehicle safety. Development, insurance companies can ultimately reduce investment. In this way, the system of testing institutions, consumers, manufacturers, insurance companies, and the four parties that contain each other and promote each other may be the unique feature of IIHS compared to other testing structures.
Of course, whether it is a 25% offset crash test, a roof strength test, or a rollover test, the ultimate goal of the test on a short 150-meter track is to promote the safety of the car. Such improvements are not achieved overnight. A few years later, when we compare new and old models to collisions, we will find such a change.