SPECIMEN TENSILE TEST

According to the CALLISTER, 2013, the test of traction can be used to assess various mechanical properties of materials that are important in a project. A specimen is deformed, usually until your fracture, by gradually increasing traction load is applied along the axis uniaxialmente longer a body of evidence. Typically, the straight section is circular though rectangular specimens are also used. During rehearsals the deformation is confined to the central region, narrower, body of proof, which has a uniform straight section over your length. The default diameter is approximately 12.8 mm (0.5 in.). The usable length is used in calculations of ductility and your default value is 50 mm (2.0 in.). The body of evidence is arrested by its extremities clamping chucks of the test device. Traction testing machine is designed to lengthen the body of proof at a constant rate, in addition to measuring and simultaneously instant load (using a strain gauge). Typically, a stress-strain test takes several minutes to run and it's destructive, i.e. the sample tested is permanently deformed, being usually fractured. The result of a tensile test of this kind is recorded on a chart recorder (or a computer), in the form of load or force into stretching function. These load-deformation characteristics are dependent on the size of the sample. For example, if the area of the straight section of the body of evidence is bent, it will be necessary to double the initial charge to produce the same stretch. To minimize these geometrical factors, load and elongation are normalized Thistle with their respective voltage parameters of engineering and engineering deformation. Engineering stress σ is defined by the relation,

where F is the instantaneous load applied in a directionperpendicular to the straight section of the sample, and A0 represents the area of the original straight section beforeapplying any load. 

The engineering strain ε is set according to the expression,

where l0 is the original length before any load being applied, and li's instant length. Δl represents the stretching deformation. See the purpose of a traction test, the team, after making the body of evidence, did the same scheduling in the mechanical testing laboratory of the Centro Universitário SENAI CIMATEC. The lab was led the body of proof until the traction testing machine, which was stuck at its ends by the claws of the machine.

Figure 1: Body of evidence in the trial. 

Source: Own team. 

Then came early to the test, where the body of evidence wassubmitted to a traction voltage and leaked to deformpermanently until your break.

Video 1: tensile Test.

Source: Own team.

At the end of the test, the results obtained through thecomputer that operates the mechanical testing machine.

Figure 2: test result of traction. 

Source: Centro Universitário SENAI CIMATEC.

With the obtained results it can be concluded that the chosenmaterial is capable of withstanding a load of 160.33 N, along a section of 132.32 mm². Besides the peakvoltage obtained was of 121.16 MPa and presented a runoff of77.16 voltage MPa, finally presented an elongation of 19.83%. 

References

CALLISTER, W. D., Ciência e Engenharia de Materiais: Uma Introdução. John Wiley & Sons, Inc., 2013.