Car Automotive

Posts Tagged ‘kinetic energy’

In the development of a new vehicle platform, its crashworthiness is an important concern, and it is imperative to compare the impact severity of the vehicle and occupants under various test and design conditions. Since an impact is a physical event that involves analyses of impulses and energy components, such as kinetic energy, energy absorption, and energy dissipation, the analyses require both the principle of work and energy and that of impulse and momentum. Although both principles are derived from Newton’s Second Law, they are not mutually exclusive when it comes to solving problems involving impact and excitation.

It will be shown that any crash event, modeled by either a single-mass or a multi-mass system, involves impact and/or excitation. Recognizing the existence of the impact and/or excitation, the closed-form formulas derived in Section can be utilized to solve problems. Case studies, such as the dynamic principles of pyrotechnic pretensioner on the occupant responses, are investigated. The preloading effect of a restraint system on the occupant response and ridedown  efficiency are discussed. Many crashworthiness topics related to single and multi-vehicle collisions are analyzed by the engineering principles presented so far for determining the degree of crash severity. Applications of these principles to vehicle-to-vehicle compatibility, shear loading of truck body mounts due to eccentric loading, and the methodology of accident reconstruction methodology are also presented.

When viewed in its broadest sense, energy takes many forms, manifests itself in many ways and can be transformed from one form to another in many complex ways. But heat is always there in some way. Let’s take a few examples. The sun, obviously, gives off vast quantities of energy, heat being one of the more obvious ones. On a smaller scale, any fire also gives off heat. The connecting rods, crankshaft and drivetrain of an internal combustion engine convert the chemical energy released in the explosion of gasoline vapors into the kinetic energy of the moving automobile, in the process creating a lot of heat because of the friction created by all those moving parts rubbing against one another. And every time the driver applies the brakes to stop the vehicle, the friction generated between the brake pads and rotors, and between the tires and the road, transforms the kinetic energy of the moving vehicle into heat.

But when you hear the word “heat,” do you think of kinetic energy, friction, internal combustion, fires or the sun? Probably not. The first thought that crosses your mind is the palpable effect of heat on your body when you are in close proximity to a heat source. In other words, the word “heat” makes you think of the physiological sensation of being hot. That’s because we humans are pretty sensitive to heat, or the absence of it.