Structural crashworthiness involves absorption of kinetic energy by considering designs and materials suitable for controlled and predictive energy absorption. In this process, the kinetic energy of the colliding bodies is partly converted into internal work of the bodies involved in the crash. Crash events are non-linear and may involve material failure, global and local structural instabilities and failure of joints. In addition, strain-rate and inertia effects may play an important role in the response of the structures involved. Crashworthiness of a material is expressed in terms of its specific energy absorption, Es=F/D, where F is the mean crush stress and D is the density of the composite material. In order to protect passengers during an impact, a structure based on strength and stiffness is far for being optimal. Rather, the structure should collapse in a well defined deformation zone and keep the forces well below dangerous accelerations. However, since the amount of absorbed energy equals the area under the load deflection curve, the two above mentioned criteria are somewhat contradictory, thus showing that, it is not only important to know how much energy is absorbed but also how it is absorbed, i.e., how inertial loads are transferred from impact point to panel supports. Therefore, in addition to designing structures able to withstand static and fatigue loads, structures have to be designed to allow maximum energy absorption during impact. There are a lot of other criteria, however, in addition to a material being crashworthy, that need to be met before one can begin the use of a particular composite as a crash energy absorber in automobiles. Some of the primary criteria are low costs involved in their manufacture, t... ... middle of paper ... ...tem Solutions) laboratories, Peenya Industrial area, Bangalore. During preprocessing, stress vs. strain curves (obtained from the tensile tests) are entered while defining standard piecewise linear rate dependent plasticity material models. The material properties of Aluminium alloy (Al6063-T6), SMC (Sheet Moulding Compound) and GMT (Glass Material Thermoplastic) are extracted from different journal papers during literature review. These material properties are required to be entered in Kinematic Hardening material model during the preprocessing stage. On the other hand, experimental rate of work decay is evaluated as area under force vs. displacement curve (obtained from three point bending tests). Experimental contributions made by few researchers in the field of high velocity impact crashes facilitated the specific energy absorption values for different materials
Collision and its Implications." Defense Technologies Information Center. 25 Jan 1994. http://www.dtic.mil/cgi-bin/GetTRDoc?Location=U2&doc=GetTRDoc.pdf&AD=ADA274926 (accessed Mar 23, 2012).
Give a brief summary of the reading. What event was it describing and how was it analyzing that event?
Today, engineers rely on damping systems to counteract nature's forces. There are many types of damping systems that engineers can now use for structures, automobiles, and even tennis rackets! This site focuses on damping systems in structures, mainly architectural variations of the tuned mass damper.
Harris, Tom. “How Building Implosions Work.” HowStuffWorks. A Discovery Co., 13 Jan. 2012. Web. 13 Jan. 2012. .
To lose is to win. These words are come from ancient China, which means a loser can gain something profitable to be defeated deliberately. People always want to win to satisfy own sense of superiority, especially teenagers and boys. In the noble, Crash, written by Jerry Spinelli, there is a boy named Crash, who always wants to win and attention. However, he lets a boy named Penn win, because he wants him to run at next Relays, to return for Penn’s gift for Scooter, and he thinks too much about his opponent. Also, he gains profit to become a loser, for example, he learns a loser’s feeling, he learns friendship, and he learns to think other’s minds.
The fractures are also closely related to bone material. There are different types of bones and wide range of properties for the same type of bone among different peo- ple. Femur bones are consist of two type, cortical bone and cancellous bone. Corti- cal bone is significantly higher in density and Young’s modulus (Dieter Christian Wirtz et al., 2000; Critical evaluation of known bone material properties to realize anisotropic FE-simulation of the proximal femur). Cancellous bone is porous, thus lower in both density and Young’s modulus. In the femur, cancellous bone mainly distributes in upper extremity and lower extremity while cortical bone consist mainly the middle shaft bone. Femur bone is light and strong which is hardly bro- ken in static state. However in many high speed impact situations femur is likely broken. The FEA(finite element analysis) method helps apply different kinds of load and force on to the femur model and reveal detail information of it.
Different collisions took place throughout the process of the Rube Goldberg Machine. This included Elastic and Inelastic collisions. An example of an Elastic Collision in our Rube Goldberg Machine is when the car went down the track and collided with another car. Elastic collisions are defined as collisions with conservation or no loss of momentum. This is proven by the first car which transferred its momentum to the second car thus momentum was perfectly conserved. An Inelastic Collision is seen in our project ...
Today safety glass, which will not splinter when exposed to shock, is in windshields for cars. Essential as it is, safety glass was the result of a clumsy mistake. In 1903, Edouard Benedictus, a French scientist inadvertently knocked a glass flask to the floor when fetching reagents. He heard the glass shatter, but later, he saw the broken pieces of the flask still hung together, more or less in their original contour. Then he learned that the flask had recently held a solution of cellulose nitrate, a liquid plastic, which had evaporated, apparently depositing a thin coating of plastic on the flask’s interior. He experimented with coating glass with liquid plastic, then shattering it and it was not broken. When Benedictus read that most of the drivers seriously injured had been cut by shattered glass windshields, he knew that his unique glass could save lives. Unfortunately, automakers were uninterested in the costly safety glass for windshields. It was not until the outbreak of World War I that safety glass found its first application: as the lenses for gas masks. After automobile executives examined the proven performance of the new glass under the extreme conditions of battle, safety glass’s major application became car windshields. It was very dangerous when something hit your car, the glass was broken and as a result, you would be sore and even dead. But with this unbreakable glass, now you don’t have to worry about this because nothing can touch you from the outside.
Even if airbags do save lives, there are still some injuries and even some fatalities linked to an exploding airbag. Around 51 people have been killed from an airbag since 1990 and 30 of then have been children. Contrary to popular belief, the airbag is not a cushioning pillow that gently breaks your fall during a car crash. Designed to propel out at speeds of up to 200 mph the air bag is designed to stop and violent thrashing forward of a body during a collision (Doherty). The sensors located in the front of a car determine weather the airbag is needed in cars with in milliseconds of the crash occurring. However these sensors are often too sensitive and this causes and airbag to so...
In a relatively short period of time, carbon fiber revolutionized the manufacturing industry due to its low weight and superb structural properties. Carbon fiber is a composite material. Composite carbon fiber is composed of a woven carbon fiber which reinforces a polymer resin (usually epoxy) [3]. The carbon fibers themselves are polymers of graphite (which has a hexagonal sheet structure) rolled into a thin filament [2]. The tensile strength (resistance to tearing from being pulled) and Young’s Modulus (force required to stretch or compress a material) are extremely high in relation to the fiber’s weight. The internal strength of carbon fiber lies in the structure of the weave and the impact resistance comes from the hard plastic polymer shell. This paper will focus on the production process of Polyacrylonitrile (PAN) carbon fiber, the applications of carbon fiber in industry, and the future applications of this revolutionary
During impact most of the impact energy in the test specimen is absorbed as plastic deformation when the test specimen yields. Temperature and strain rate effect the yield behaviour and ductility of the material and hence affect the impact energy. Materials that behave this way usually have body-centred cube crystal structures and where lowering the temperature reduces the materials ductility.
There is an old saying that any landing you can walk away from is a good landing. There is a lot of truth to this statement, especially if you are the one walking away. Here are the stories of two such landings that I am personally familiar with. Since they are both very similar in nature, they will be discussed simultaneously in the pages to follow. N9KF was a Model 1 Kitfox. It was built and flown by my father. The Kitfox is an experimental, homebuilt kit plane. Every plane, like every person, has a story. This is the story of N9KF or at least the story as I know it.
This report is based upon extensive library and internet research as well as an interview with Zaman Qamar, performance engineer at General Motors. He is one of the team members for crash and safety department which deals with accidental issues during severe crash.
Crumple zones- are a structural feature used in automobiles. They help by absorbing the impact; this is by spreading the impact through parts of the car instead of in the one spot. This reflects back onto law number one, two and three. This is shown when the car hits the object it causes the car to slow down or completely stop (1). The crumble zone would protect the driver because all the energy has been diverted around the car, instead of the one spot. As a result of the cars mass and its acceleration, the force can be calculated (2). When the car crashes it’s most likely that the object w...
Earthquake Engineering is a branch of Civil Engineering that is in charge of protecting the society from natural disasters like Earthquakes. This branch of Civil Engineering mainly studies how structures behave when they are hit by a seismic wave. Earthquake engineers main responsibilities are to design structures that can stand an earthquake and to make sure that all structures have the required building codes. In addition, they need to estimate the probable damages to structures after an earthquake.