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Numerical and experimental analysis of the triggering mechanism of the passive square thin-walled absorber
Published in Alphose Zingoni, Current Perspectives and New Directions in Mechanics, Modelling and Design of Structural Systems, 2022
Michał Rogala, Jakub Gajewski, Robert Karpiński
Today, passive safety is a particularly important design aspect of mechanical structures. Vehicles have specific crumple zones designed to protect vehicle components during a road crash. Particularly important is the crash-box, which protects the passengers in a frontal collision at a maximum speed of 15-20km/h without damage to the vehicle stringers. A passive energy absorber is characterized by the fact that, with certain design assumptions, the structure folds like an accordion to absorb mechanical energy without generating large overloads. The field of energy absorption by vehicle protective components began in the early 1960s. Before that, vehicles had rigid steel bumpers to protect the occupants, but because of the overloads generated during an accident, they could be fatal to the passengers.
Hot Rolling System Design for Advanced High Strength Steels (AHSSs)
Published in Jingwei Zhao, Zhengyi Jiang, Rolling of Advanced High Strength Steels, 2017
The two generalized areas of the car—the front and the rear end of the vehicle and the passenger compartment have very different safety requirements. The passenger compartment, enclosed in a rigid “safety cage”, as shown in Figure 9.3 above is designed to protect the passengers in the event of a low- to high-speed crash; the structure should prevent any deformation or intrusions that would compromise the integrity of the structure and impinge on the space around the passengers. The so-called “crumple zones”, (Figure 9.3) located at the front and rear end of the vehicle, are designed to absorb as much energy as possible in the event of a front or rear collision. By absorbing the impact energy over a distance, the crumple zone will cushion the impact and help preserve the structure of the passenger compartment. The general guidelines for materials selection in these zones are outlined below:
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Published in Splinter Robert, Illustrated Encyclopedia of Applied and Engineering Physics, 2017
[general] A mechanical resistive device, for instance, by means of viscous flow through a porous structure under the influence of a moving piston or resulting from contact friction. The equivalent in general mechanics is the use of a crumple zone in cars to absorb the energy involved in a collision. The mechanical deformation provides the mechanism of conversion of kinetic energy in order to prevent exposure of the driver and passengers in the car to the full impulse (see Figure D.9).
Crashworthiness parameters and their improvement using tubes as an energy absorbing structure: an overview
Published in International Journal of Crashworthiness, 2022
These crumple zones are the parts of car frame, which gets deformed and crumpled after collision. When looking into the design part of this crumple zone, the other major factors like mass and dimensions of the car, stiffness of car frame, and stresses affecting the car frame needs to be considered. Basically, crumple zones are designed to achieve two objectives, primarily to reduce the initial kinetic force involved and secondarily, redistributing these forces to other parts of vehicle before it reaches to the occupants. To reduce the initial impact force, acceleration of the car needs to be slowed down. As we know from Newton’s second law, force is equal to mass times acceleration. Due to this, small reduction in acceleration of car can reduce the large amount of impact force. But, if the reduction in acceleration is achieved by hitting the rigid parts of vehicle like engine and occupant cell, then it will attract the large impact force and will further transfer it to the occupants. Therefore, these area of rigid parts like engine and occupant cell, needs to be surrounded by crumple zone.