Mechanical behavior and fracture characteristics of polymeric pipes under curved three point bending tests: Experimental and numerical approaches

Abstract

This study describes an investigation of the load–deflection response of the material used for production of polymeric pipes. Three point bending tests were performed on curved pipe samples to evaluate their flexural properties, namely the flexural strength, the modulus, the strain to failure and the mode of failure. Effects of various configurations and parameters are investigated: effect of internal or external loading, effect of notch, impact of aging, combined effect of notch and aging. In addition, FE models are established to predict pipe material response under flexural loading. From the main results, the average flexural stress–strain response of pipe material is characterized by a linear portion curve, followed by a non-linear deformation up to the ultimate failure stress. A ductile behavior was observed, but with a brutal rupture at the peak flexural stress. The flexure behavior of the pipe material depends also on the configuration, and it behaves differently under internal and external loading. The presence of notch in pipe material reduces its mechanical performance. A significant decrease of flexural properties was observed for hydrothermal aged pipe samples. The combined effect of both hydrothermal aging and notch affects dramatically the flexural performance of pipe material. Consequently, the service life of pipe structures risks to be reduced. Finally, a coupledexperimental–numericalapproach for the characterization of pipe material behavior under flexure loading has shown a good correlation, and therefore, the efficiency of the established FE model to predict the flexural response of pipe structures.