The aim of this paper is to present the behaviour of specimens made of polyethylene material PE 80, subjected to tensile load until failure. Measurements of the temperature distribution have been done using the infrared thermography during specimens loading. Finite element analysis was performed in ABAQUS software, where numerical models were made based on the thermograms and force-dis-placement diagrams obtained from these experiments. Afterwards, results from the simulation were compared with the experimental results and it was deter-mined in which way the model can be optimized so that these results comply at an acceptable level. Numerical model has shown that the highest values of plastic strain were located near the notch. Value of this plastic strain is several times greater than the values in the remaining parts of the specimen. The numerical analysis also determined that defining the load in displacement form was a much better solution than defining it using the force, since the results have shown much better compliance, and the calculation time was much shorter in this case.