Towing my car AWAYY!!!

The above picture is of a Hydraulic vehicle ramp that provides a simple method of raising a vehicle from the ground, for the easy transport. Getting your car in and out of a trailer will require a ramp. This trailer has a hydraulic tilting bed, where the entire bed can lower into position to form a ramp, and then return to a level position for transport. These types of trailers are extremely useful, but they're also quite expensive.
This trailer has a "beavertail," a downwardly curved portion at the rear of the bed that effectively provides a ramp for your car (This can be used in conjunction with some of the ramp). In some cases it may be necessary to raise the front of the trailer with a hydraulic lift in order to lower the beavertail to the point where the car can be driven on to it.
Once the ramp is in place, the car can be driven on board or it can be hauled on board with a winch. The winch, which can be attached to a secure portion of the car, is usually operated by a motor. And once the car has been raised onto the trailer bed, it must be carefully positioned. Placing the car too far forward or too far to the rear can affect the trailer's stability. And, if the trailer is an open one, care must be taken that the tires are solidly on the bed and not hanging over one side.
Ramp is inclined at a certain angle from the ground. The weight of the produces downwards forces; compressing the inner face of the ramp and the outer face of ramp is under tensile stresses. As the wheel is in contact with the ramp; reaction forces are produced in order to keep the car stable on the ramp. There is strong friction force between the tires and the top face of the ramp that helps the car to be stationary (static friction). Bending moment is also observed about the bottom end of the ramp due to the weight of the car.

Picture Taken by, Ahsan Iqbal, 20-02-2009

My best friend's Umbrella

Picture taken by: Ahsan Iqbal, 09.03.2009


Image taken from: http://en.wikipedia.org/wiki/File:Parts_of_an_Umbrella.svg

Umbrellas are something that I have always taken for granted and never bothered to explore the science behind the curtains. This has been an eye opening investigation on my behalf and hopefully you feel the same.

The umbrella operates on a very simple idea; it is an instrument designed to protect from rain or sunlight. The structure of an umbrella consists of a hollow tube that has a spring running through it, a runner is a part that moves up and down on the tube facilitating the opening and closing of the structure. The upper part of the protective structure consists of ribs that are connected to the top of the umbrella; the stretcher is joined to the runner and acts as the connection between the ribs and the runner.

An umbrella is opened by applying upward force on the runner; this results in pushing the ribs outwards to form a canopy. This action produces tension in the stretcher as well as in the joints at the end of the stretcher. The main issue in constructing an umbrella structure is its apt operation below the elastic limit of the materials used in the construction; so the material returns to its original shape once the runner is released (pushed downwards). Another key matter in the design of an umbrella is the precise rib distribution (hexagonal, octagonal, and so on depending on the size of the structure) about the tube at the center; to balance the weight once the umbrella is opened.

The only external force applied to the structure is that produced by wind; this applies bending moment about the tube and tension in the joints of the stretcher and the ribs alike.

Glass Roofs

Picture taken by: Ahsan Iqbal, 09.03.2009

The above pictures are of a glass roof for the entrance of the car parking in Birmingham City University. This glass roof consists of a number of beams supporting the glass structure. At the top of the glass structure there are 4 long flat metal beams; the ends of which are joined to another metal beam that is then connected to the side. There is also a thin beam running across perpendicular to the long flat beams giving rigidity to the structure.

The weight of the structure is supported by additional two beams going diagonally across forming an X-shape figure that will actually help to give stronger support at the center; as the center of gravity lies at that point. The weight of the structure produces tension in the supporting metal beams, the wind adds on to this tension by producing a bending moment.

The accurate management of possible torsion and bending stresses produced by the wind is a key factor in the success of such a complex structure. The key elements of the design are: material strong enough to withstand the stresses produced, construction method of support to provide rigidity to the structure and durability of the structure as damage or destruction can have serious effects.

Ladder Science!!!

Picture Taken By: Ahsan Iqbal, 15/02/2009

Hello again guys, this week I am going to talk about a step ladder that has two extendable lengths for more convenient storage, the lengths can be slid together for storage or slid apart to maximize the length of the ladder. It also has a small horizontal platform at the top. The ladder is hinged in the middle to form an inverted V, with stays to keep the two halves at a fixed angle providing support each end and helping it not to tip over. The ladder is in static equilibrium as the sum of all the horizontal and vertical forces acting on the ladder is equal to zero and the moment about at any point along the ladder is also zero. The most interesting thing is the friction at the ends of the ladder. Friction force is large enough to prevent it from slipping.

Material selection plays a major role in the structure of the objects under stress. In the case of ladder, material used is aluminum that is light weight, soft, durable and malleable metal. Aluminum is able to withstand the extensive stresses on the structure of ladder and hence is makes it safe for use.

Crane

A crane is a lifting machine equipped with a winder, wire ropes or chains and sheaves that can be used both to lift and lower materials and to move them horizontally. It uses one or more simple machines to create mechanical advantage and thus move loads beyond the normal potential of a human.
In order for a crane to be stable, the sum of all moments about any point such as the base of the crane must equate to zero. In practice, the magnitude of load that is permitted to be lifted (called the "rated load") is some value less than the load that will cause the crane to tip.
The moment created by the boom, jib, and load is resisted by the pedestal base or kingpost. Stress within the base must be less than the yields stress of the material otherwise the crane will fail.
Cranes, like all machines, obey the principle of conservation of energy. This means that the energy transferred to the load cannot exceed the energy put into the machine. For example, if a pulley system multiplies the applied force by ten, then the load moves only one tenth as far as the applied force. Since energy is proportional to force multiplied by distance, the output energy is kept roughly equal to the input energy. In practice output energy is slightly less, because some energy is lost to friction and other inefficiencies.

Picture by: Ahsan Iqbal, 08/02/2009

I am Ahsan iqbal, 2nd Year Mechanical Engineering student at Aston University. I have been fascinated by the way things work and the forces involved in them. This interest made me work harder and get better grades in physics and mathematics and hence I chose Mechanical Engineering as my degree. My interests include experimenting with different ingredients to cook healthy food, watching BBC food, gaming and playing cricket. That is it for now wait for my next blog.

Door Hinge:

Door hinge connects the door with the wall. Door hinge is a simple example of Newton’s third Law of physics, as the force acting on the wall by the door is equal to the force acting on the door by the wall and acting on opposite direction. In this particular case, keeping in mind the general principle of mechanics, door and the hinge are in equilibrium. Perpendicular component of the force acting on the door knob produces a moment about the door hinge. It is easiest to open the door by pushing the door knob as the moment is larger the farther away it is from the hinge. Pushing at an oblique angle to the door is less effective and the door will not open if one pushes towards the hinge.

(Picture taken by Ahsan Iqbal, Date: 03/02/09, Topic: Door Hinge)