4th Post: Machines and mechanisms

We say that a structure is stable when it remains in equilibrium even when a force is applied to it.
The centre of gravity is the point where thr weight of an objet is considered to be concentrated.

• we use the word machine to describe a set ofelements or parts that work together and use energy to perform a task and obtain a result.

• Elements of a machine

Diver element: feeds energy to the machine

Driven element: receives the force produced in the machine.

Converting and transmitting element: transtmits or converts the motion from the driver element to the driven element.

A mechanism is a device that transmit and/or covert motion.
Motion transmission mechanisms: The mechanism is fed energyfrom the driver element and simply transfers it to the driven element. for example: Linear transmission mechanisms
Motion conversion machanisms: The mechanism converts the movement from the driver element into a movement that the driven element can use. for example: Eccentric

                                       Lever

 A lever is a rigid bar that can pivot on a point of support called a fulcrum.

                                          Pulleys

              Pulleys are used to lift heavy loads. They are eheels with a grooved rim.

                   Belt and pulley system

This system is made up of two pulley wheels joined by a belt that slots into the grooved rim of the wheels.

 Gears

A gear is a mechanism consisting of two wheels with teeth. There are gears in the correction tape dispenser 

3rd post: Stresses and Rigidity

stresses are the physical demands that a body or object must whithstand when one or more external forces are applied to it
there are 5 types of stresses

Compression: This is caused by forces acting on a body that tend to flatten it or reduce its length or thickness.          

         

• Tension: This is caused by forces acting on a body that tend to stretch it.

• Bending: This is caused by forces acting on an element that make it curve or bend.

• Torsion:this is caused by forces acting on a body that  make it twist

• Shear:this is caused by two equal forces applied in opposite directions that act on lines of action close to each other.

2nd post

A structure is a collection of elements arranged in an optium way to support a body or an object.

Mass structures: These are solid, heavy, and very stury structures. Like walls,dams, etc.

Frame structures: These structures are formed by columns and beams that act as supporting elements. One example is the structure of a building.

      Truss structures: These structures  sre composed of bars that form triangles. They are lightweight and sturdy.For example electricy pylons

Suspended structures.these are held in place by cables and suspenders attached to sturdy supports.For example bridges, tents, etc

a force is an influence thatcan deform a body or change its movement or produce motion in a body at rest.

stresses are the physical demands that a body or objet must withstand when one or more external forces applied to it.

Presentation

Hi guys,we are Aaron and Noemi. We are from Spain and we are going to talk about  STRUCTURES in our blog.
We hope that you like it.