Name: Ahmad Alowais Class: ME476C Individual Analysis Team 20: Wonder Factory A Instructor: Dr. David Trevas

Transcription

1 Name: Ahmad Alowais Class: ME476C Individual Analysis Team 20: Wonder Factory A Instructor: Dr. David Trevas

2 Introduction: Packaging engineering involves itself with the designing and creating of cartons, boxes, bottles and other packaging materials. It uses the chemical, physical and industrial factors for the formulation of these products. These inventions include helmets, pads, bubble wraps, peanuts packing cartons, and airbags Ever since helmets were put on, hundreds of years, by the Roman fighters in the Bible, we use them for various purposes. One, in sports events, where the current American footballers use them for head protection as they indulge in sports activities. This equipment can be used by the firefighters in all sector of life, as they attempt to put away fire hazards. The common pads worn by the footballers, hockey players, and basket players are some form of defensive materials that aid them from injuries. Though this type of engineering is not measured as a formal branch of the mechanical, chemical and physical based sciences, it borrows ideas from these subjects. It continues to be an area that continues to be relevant in what happens in today s world. It has major applications in the above-mentioned areas. Examples are helmets, head covers, infant car seats for protecting children, and sports pads. Automobiles use the present technologies to offer the safety of passengers. Problem design: Problem design problem starts by developing the model for this specific helmet. The survey data collected from the experiment is then used to come up with an economic helmet in terms of regarding costs. A literature survey is conducted to address the customer s needs and demands based on our design costs. Then we proposed helmet product that targets consumers, footballers, hockey players and race. Next, the designer provides the cover s specification. Most of these covers are designed based on the scientific facts and verification. Therefore the resulting product must absorb impact s energy in such a way that, it has a predetermined weighed of 300 grams. The shell should avoid falling at an angle of 60 degrees to the ground. This particular attribute affects the thickness size of the shell of the merchandise. The final product should be lightweight and offer ventilation. Motorbike Helmet Parts It is made up of four components namely the outer shell, impact absorbing liner, the comfort padding and the retention system. The outer shell is the first part visible to one s eyes. It is made of fiber-reinforced material called polycarbornate.it is a tough material that compresses whenever it hits the ground. Inside the shell, there is the liner that absorbs shock. Both the two layers, compresses if they are hit hard by any moving material or falls down. Unless hit hard, they crack and break. The comfort padding is the soft foam layer that sits next to one s head and provides comfort. Lastly the retention

3 system is the strap that keeps the helmet on one s head. The band is connected to each side of the shell. When you put the case on, you fasten it securely[1]. Motorbike Helmet Analysis While the color, the design and the part of the involved factors to consider before assembling one, a designer cannot do away with the comfort and protection elements. There are many materials that can be used for making of these cover elements. For example, cotton, linen, wool, silk, and hemp. Cotton is cheap and readily available.the major disadvantages include; it holds sweat and gives the wrong look or appearance whenever used. Materials used for staffing the cover come in variety; these are horse air, linen scraps, and tows. Hard-shell elements are more robust than the foam ones but heavier. A hybrid type combines both, and has a thinner hard outer shell but again slightly lighter than the hard-shell type to prevent deformation whenever an accident occurs. The foam elements are warmer because of the high isolation.hardshell helmets offer protection against impacts from above. They are most used in mountaineering and long distance routes. Foam provide impact from all direction, therefore they are suitable for sports. Cotton material is used because of its good tensile and elongation strength. The material contains high number of twists that increases the strength of each yarn. It has the highest value of water permeability, when it absorbs water they become bulkie.since the inner padding layer of the helmet matters, this fabric can be used. Foams are light and cheap. They can be cleaned with soap and water. They material used to make these devices are shock absorbent and fully ventilated. They provider great impact resistance than any other soft helmets. Besides these, they give they give the front and the back of head protection without obstructed vision through an open face design [2]. Papers are the cheapest materials available, and have minimal weight but poor ventilation. They are less water resistant as compared to other materials. They cannot be used in ice climbing, warm weather sport climbing and belaying.

4 Methodology and Analysis The following analysis was done based on the material used for making these covers. The sample materials included papers, foams and cotton. The results were recorded as follows Material Light Weight (out of 10) Durability (out of 10) Breathing (out of 10) Cheap (out of 10) Effectiveness Risk Priority Number calculation Cotton Foams Papers Table (1) The Risk Priority Number is given by multiplying the five factors of the material used Risk Priority Number= Light Weight X Durability X Breathing X Cheap X Effectiveness Therefore the best is the use of foams. Impulse Force and Momentum The impulse force refers to the force acting on an object for an interval of time leading to a change of momentum. The impulse hence is critical in the analysis of the collision impact of force. In other words, impulse forces depict the short interval forces that lead to rapid changes in motion [3]. On the other hand, momentum refers to the impetus that a moving object gains. Momentum, therefore, depicts the quantity of motion occurring in a body or a mass in motion. In other terms, momentum illustrates the strength and difficulty experienced in stopping an object. Impulse force and momentum, therefore, relates in such a way that when a force acts on an object for a short time interval, the force is referred to as an impulsive force because it shall result in a shift in momentum[3]. Momentum is hence dependent on the on the impulse force. The equation of the impulse on an object is given by: Force (F) = Mass accleration Force = Mass (M) Velocity(V) Time (t)

5 Ft = m v On the other hand, the equation of momentum is given by the product of mass and velocity. However, momentum is a vector quantity provided by the formula below [4]. p = mv The figure below illustrates the impact of impulse. Figure (1) From the video, two eggs were thrown using the same force. One of the eggs lands on a wall and the others lands on a piece of sheet. As a result, the egg that falls on the wall crushes while the one that lands on the sheet of cloth does not crush. Regarding the analysis of the impulse force and momentum, both of the eggs have same initial momentum because both of them have similar mass. Moreover, the eggs are also thrown at the same velocity in the same direction. However, the egg that lands on the wall crushed because it had a sudden change in its momentum. The impulsive force on the egged acted for a very short period. As result of this, there was a sudden change in momentum which caused the egg to crush because of the high impulse. On the other hand, the egg that landed on the hanging piece of sheet did not change because of the delayed change in momentum. The impulsive force on the egg acted for an extended period. As a result of this, the shift in momentum took place for a prolonged period making the egg not to crush because of the less impulse. If assumptions are made such that the velocity of an object is 10 m/s, the momentum of the object is lower than when the object is moving at a speed of 20 m/s. However, the impulse would be high in the object moving at 20 m/s. For an equal rate of change in momentum, an object moving at 20 m/s shall need more time. If an object moves at 100m/s, it has a higher momentum, and it shall have a strong impulse. The racer helmets are designed in such a way that they are hard on the outer part to distribute the force of impact over a large area [4]. They

6 are spongy on the inside to enable the soft part to absorb some of the force and increase the impulse time while minimizing the impulse force. Conclusion A helmet can be subjected to a load or a force. We analyze the strain energy, deformation, strain energy and the equivalent stress. In the dynamic analysis, the total helmet deformation is estimated and compared with the standard experimental data. The impact energy is influenced by how far the cover drops (drop height) together with the mass. The injuries to the body parts especially the head take various forms. Some experimental measurements deduce that whenever foam is used, there is a high resistance to impact force. a prolonged change in momentum results to reduced impulse force while a sudden change in momentum produces a large impulse force.

7 Work Cited [1] A.Gilchrist, N.J Mills, Fast fracture of rubber-toughened thermoplastic used for shells of motor Cycles, [2]Sample Module, Eggxpress-Egg Drop Project, California, [3]Giancoli, Douglas C. Physics: principles with applications. Pearson Education, [4]Lawson, Ronald A., and Lillian C. McDermott. Student understanding of the work- impulse-momentum theorems. American Journal of Physics 55.9 energy and (2007):