You enter the springboard for jumping into the water, and your heart begins to beat faster. You are worried, of course, there is no fear that the board will break, and one is reverent before the jump. However, let’s talk about something else: here, the board bent. I wonder what is happening inside her?
The board in the section.
Under the load, its end is lowered. The upper part is slightly lengthened. The material occurs in the material. The inside is shortened. The material is compressed. The middle layer of the material does not change in size, its reaction is neutral. In fact, the board behaves like a console that, leaving the wall, supports the balcony, or as a bracket fixed on the wall and supports the book shelf. This is the beam – the main element of mechanical structures and buildings. The more the material from which it consists, it resists stretching and compression, the less the beam deforms. So, it has become well behaved in both cases. But the stone resists compression well, but easily breaks down with stretching. Almost the same thing happens with concrete. Reinforced concrete was invented to overcome this lack.
Game with forms.
The rigidity of the beam also depends on the shape. Since the layers are included in the work, the most remote from neutral, they need to strengthen. Check this by conducting the following experiment. Put a sheet of paper on two books between which free space remained. You can’t put a single large object in the place of this gap on such a thin beam so that the structure does not break. And now put a sheet of paper in an accordion, and now it already has a different rigidity, strong stretching, the surge resists only the lower and upper ribs of this multiple beam, the flat surface serves only for the connection between them. This principle underlines the architectural breakdown of the double -rotary section, its shape, which you met many basic structures of metal beams. The wide supports of the double-barrel beam are opposed by the force of stretching and the sabotage, and the vertical part of the rally can perform the function of their connection with the neutral layer. The material is saved, the design is facilitated, and the rigidity is facilitated. In construction, beams with triangular compounds called farms are often used. Inclined beams carry a roof, which in turn should withstand a layer of snow. The farm can be compared with the circul, the top of the farm – its hinge, and two side beams – the legs of the circul. So that the compass is not revealed when it presses on a hinge connection, it is enough to connect the ends of the legs with a rope that will withstand stretching. The same thing happens when the beams are connected to the triangle. The horizontal beam of the farm also works for stretching. So, it can be replaced with a thin steel rod. That is why the principle made many metal structures to many. Look up under the roof of the station or market. Elements operating and stretching, beams; Elements that work only for tensile – thin hands or slings Dyneema.