structures
A shell structure is one in which the strength reloads into the outer surface. They are usually lighter than frame
structures. For example, A turtle, an egg, an airplane, a boat, a lobster or a car has a shell structure .
In a structure the form is very important. The resistance of the structure depends on its form. A good example is an
egg.
SHELL STRUCTURES
Sometimes we use objects that are a combination of both structures. An example is a Chair. There is a tubular steel
frame structure ( whose function is to support the load ) and a shell structure (piece of wood, plastic or metal which you sit on ).
They are structures that have a skeleton associated with them. A example are leaves with frame structures and skin on them.
If they have no “skin” on them, they are called “open frame”.An example of a natural open frame structure is the spider's web.
FRAME STRUCTURES
Test: Get an egg and place it vertically between your index finger and your thumb. Now squeeze hard. You will see that however hard you squeeze, you will not be able to break the egg. You can even do it with both hands, by interlacing your fingers and squeezing the egg between them so that force is applied at both the lower and upper ends of the egg.