Robust set up of experimental procedure for monotonic tensile test on polyethylene specimens

Polyethylene pipes for water conveyance may present sensitivity to disinfectants employed to assure water potability. In particular, chlorine based disinfectants could affect their structural properties, which are mainly assessed through monotonic tensile test. A systematic experimental plan, performed to investigate the effects of chlorine based disinfectant on the mechanical properties of PE pipes, emphasized the high variability of the measured parameters, in particular with regard to percentage elongation at fracture. A research aimed at identifying whichfactors affect the outcome of the monotonic tensile test, and which combination of such factors provides a robust setup of the experimental procedure, is presented here. A systematic approach has been adopted considering a fullfactorial experimental plan, and varying each factor between two levels. From the outcome of the experimental results the influence of the test speed, the cutting die, the cutting direction and the pipe diameter has been assessed.