For more information click here.Įvery student at WPI must complete the Humanities and Arts (HUA) Requirement. GPS courses run for both A and B term, so you will only need to choose one. These courses are helpful with the transition to college as well as useful for students when preparing for projects such as IQP and MQP in junior and senior year.
#PHYSICS TERMS HOW TO#
GPS stands for Great Problems Seminar is a course that is exclusively for first year students and allow students to learn about a problem in the world and work with a group on how to fix it. More information is available about these courses below. So if you want to know exactly what the deployment algorithm stored in the SDM is, just do what GM has done: Crash thousands of cars and study thousands of accidents.Your third course should be a GPS or Humanities and Arts course.
#PHYSICS TERMS TRIAL#
Accidental airbag deployments would, after all, attract trial lawyers in wholesale lots. Today, manufacturers want to make sure that what’s occurring is in fact an accident and not, say, an impact with a pothole or a curb. The SDM also knows whether a belt or child restraint is in use. Those determinations are made from information provided by seat-position and occupant-mass sensors. In fact, the maximum pressure in an airbag is less than 5 psi-even in the middle of a crash event.Īdvanced airbags are multistage devices capable of adjusting inflation speed and pressure according to the size of the occupant requiring protection. Since there’s more space between the passenger and the dashboard, that airbag has a larger volume and takes more time to fill.īut even as it is filling with nitrogen gas, an airbag is already venting so that when the human body makes contact, it’s not running into the equivalent of a fully inflated Pirelli P7 radial.
#PHYSICS TERMS DRIVER#
Hurtling forward at 30 mph, an unbelted driver moves through the space between his chest and the wheel in 23 or so milliseconds.
Think of it as supersonic Jiffy Pop, with the kernels as the propellant.Ī 2.5-cubic-foot driver’s front airbag inflates in as little as 20 to 30 milliseconds. When the mechanism is triggered, an electric charge heats up a small filament to ignite the chemicals and- BLAMMO!-a rapid reaction produces a lot of nitrogen gas. The solid chemical mix is held in what is basically a small tray.
Sodium azide, the original preferred chemical, has been superseded by less toxic gas-generating material. Manufacturers use different chemical stews to fill their airbags. If the algorithm commands an airbag deployment and the arming function in the SDM concurs, electrical power is provided to the airbags to begin deployment.” All that generally happens within 8 to 40 milliseconds of the initial impact. To decide if bag deployment is warranted, the SDM considers signals from multiple accelerometers and door-pressure sensors. After the algorithm is initialized, the microprocessor compares measured vehicle deceleration and other calculated values with calibration parameters stored in the SDM that were developed from many deployment and non-deployment crash events. The clock starts the instant the tip of the car’s nose hits concrete.Īs Zawisa explains, “The deployment-control algorithm in the sensing and diagnostic module (SDM) is initialized when an internal accelerometer senses a possible collision. For illustration’s sake, imagine a Corvette hitting a bridge abutment head-on at 30 mph. But while “supplement the seatbelt” is the mission of airbags, federal regulations require that they be tested and made effective for unbelted occupants, vastly complicating their task.Īirbags must do their work quickly because the window of opportunity-the time between a car’s collision into an object and an occupant’s impact into the steering wheel or instrument panel-lasts only milliseconds. They are designed to supplement seatbelt restraints and help distribute the load exerted on a human body during an accident to minimize the deceleration rate and likelihood of injury. They are, instead, shaped and vented nylon-fabric pillows that fill, when deployed, with nitrogen gas. The term “airbag” itself is misleading since there’s no significant “air” in these cushions. COURTESY OF THE INSURANCE INSTITUTE FOR HIGHWAY SAFETY