Sistemas Case

Sistemas

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Marco Teorico

To start any test on a piece, you must first know the material that will be used in the same piece, this to learn more about their mechanical properties. In this lab, we did just that, the pursuit of the mechanical properties of different materials, or materials with different shapes, which were tested using a tensile test. This type of testing allows us to obtain the mechanical properties real material, with this information it is possible to know the properties of different materials and thus to have a catalogue of material selection for different applications. It is noteworthy that materials to be selected, is not limited to ductile materials, they also try fragile materials (glass, ceramics). However, should mention that rehearse ductile materials can be of greatest interest since that evidence that brittle materials cannot bring because of its very nature. In particular refers to the plastic zone that is non-existent in brittle materials.

What makes the tensile test is to test the resistance of the material on a single axis, in this case a voltage, this tension is given by the movement of the load cell connected to the frame, which are in charge of "stretching" the specimen, this must be done at a constant speed and not a constant force, since what we want is to know how much effort hold our part This is carried out by moving at a constant speed of a screw, which moves directly to the frame that is connected to the load cell. It is important to note that all the specimens that we use must satisfy the standard ASTM E-8, this to have standardized results, and that they can be replicated in a global way. The advantage of this standard is that it allows us to use a certain range of dimensions of specimen, same that must be specified to report the results of the experiments carried out. These specimens must have two areas of grip, which will be supported by Jaws, must have a thinner section, which will be which will be exposed to the fracture, likewise, must have a progressive reduction of the diameter profile to not change suddenly. This serves to avoid hubs of efforts in unwanted places. Below, is the outline of a test tube that conforms to ASTM E-8.

In the same way, the machines with which are made these experiments should be calibrated in a specific way, sticking to the same standards ASTM, for that will deliver relevant search results. It is important to mention also that experiments should be performed under certain specific temperatures, which otherwise could also modify the results, since metals tend to rise its ductility when subjected to high temperatures and vice versa. The results that throw us the tensile test you can see on a graph stress - strain, to be more specific: effort to stress – deformation.

What you get because of a tensile test should look like the figure above, these graphs we are very useful, since they allow us to see various data, mainly

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