One of the final stages of Vehicle Development, Misuse Testing is conducted before a vehicle is approved for mass production and released in worldwide markets. In these tests, various aspects such as acoustic, driving dynamic and aerodynamic behavior, crash safety and the structural durability of a vehicle are assessed.
A Vehicle Misuse Test explores the possibilities and extent upto which a vehicle can endure extreme situations such as driving into a sandbank, wooden beam, over a ramp, vehicle rolling over, or becoming airborne. These tests validate chassis components and chassis system behaviour while also ensuring the correct level of calibration of passive safety ECUs(Electronic Control Units) to avoid crash mis-detections. These situations can be extremely dangerous in real-life scenarios and can cause injuries to test drivers when done repeatedly. For this reason, many Vehicle Testing Companies are increasingly employing driverless robot systems suitable to perform harsh testing.
Programs like the Australasian New Car Assessment Program(ANCAP) publish the results of these safety tests and the level of occupant and pedestrian protection provided by different vehicle models for the benefits of consumers. Additionally, the Australian Design Rules (ADR) set guidelines covering issues such as occupant protection, structures, lighting, noise, engine exhaust emissions, braking and a range of miscellaneous items. All the road vehicles must comply with the relevant ADRs at the time of manufacture and supply to the Australian market.
How Misuse Testing is Performed?
In a typical Vehicle Misuse Testing Operation, several scenarios are tested and the vehicle is driven through different extreme events, such as potholes, ramps, jumps or curbs. Those scenarios may not represent common situations a customer may face on open roads and would force the car to work over their normal operational limits. During these manoeuvres, different sensors and systems are utilised to closely analyse and evaluate occupants’ safety, vehicle design and software calibrations.
The test facility generally includes a 300-400 hectares proving ground and test facility complex. The vehicle is driven through different extreme events, such as potholes, ramps, jumps or curbs and evaluates their safety and performance. Generally, the following tests are conducted as part of a misuse testing.
Chassis Misuse Test
The chassis is the most crucial structural element of a vehicle upon which all other systems and their components are mounted. It must have a very high factor of safety and reliability. Therefore, the load spectrum for each component is analysed during these tests. Data from sensors including strain gauges, displace-ment transducers or load cells installed in the suspension components are collected to evaluate the movements and deformations within the chassis.
There are several factors responsible for the activation of an airbag. These factors include the nature of the crash, the design of the airbag system, and the location of the crash sensor. Ideally, airbags are not supposed to deploy in every collision. If a vehicle hits a curb or a large pothole, the airbag may suddenly inflate. This accidental deployment may cause the driver to lose control and actually have a collision due to the accidental deployment.
Moreover, airbags that are deployed too aggressively are likely to cause injury than safeguard the occupants of the vehicle when deploying in low-speed crashes.
To test the efficiency and effectiveness of airbags, vehicles undergo tests to determine whether airbags or other elements of passenger restraint systems are deployed only when required and not in any non-collision situations. All of these systems use a number of vibration sensors including accelerometers and gyro-scopes mounted at different positions on the vehicle bodywork. These tests are carried out at different impact speeds and decelerations to determine whether the deceleration threshold to trigger the airbag is recognized correctly.
Vehicle Roll Over Tests
In order to study vehicle and occupant dynamics, vehicle structural performance, and occupant protection countermeasures in rollover accidents, several rollover test methods are conducted. Exponent has the capability to conduct a variety of static and dynamic tests to assist in these evaluations. The test involves understanding each vehicle’s reliability and the strength of vehicle pillars that hold the roof. The pillars should be able to resist the load they receive when rolling over several times.
The test data collected during these rollover tests is analysed synchronized with the high-speed video for analysis and presentation purposes.
Recording the Test Measurement in Real-time
Traditionally, products were tested in an unstructured and highly subjective manner. For instance, engineers often relied on visual or manual examinations when testing a new suspension in a vehicle. The misuse test data from external sensors and vehicle inbuilt sensors need to be collected and recorded in real-time, especially when the vehicle is being tested against many inputs. As the tests are conducted against very harsh conditions with high speeds, it is very crucial to record data synchronously at high sampling rates to analyse the actual condition of the vehicle during the tests. With visual inspection of the recorded data, it is possible to analyse the data very well and detect even minor problems.
Today, Data Acquisition Systems are considered very essential when it comes to testing any kind of vehicle, large or small to measure their performance, safety and reliability. A reliable Data Acquisition System helps in synchronizing and monitoring all the data from different sensors in real-time. These DAQ systems generally enable data recording, data storing, real-time visualization, data analysis, and many other advanced features.
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