Effects of Punch Test Conditions on the Mechanical Response of Polyethylene Materials

Polyethylene (PE) materials have been widely used in industrial and living fields such as natural gas pipelines, drainage pipes, sewage pipes. Punch test is an interesting tool for studying the mechanical properties of materials. However, the deformation behavior involved in punch test is complicated, it is, therefore, essential to investigate the influence of punch test conditions on the mechanical properties of PE materials. Punch tests have been carried out on PE specimens with different punching speed (0.01, 0.1, 1, 10 and 100mm/min) and different punch head diameters (4, 6, 8 and 10mm). The experimental results show that the maximum load from the load-displacement curve increases with the increase of the punch head diameter under the same punch speed. When the punch speed is slow, the force-displacement curve of PE specimens contains four typical stages, namely, elastic stage, yield stage, strain softening stage and strain hardening stage. However, the PE specimen breaks before reaching the strain hardening stage when the punch speed is fast. Similarly, the maximum load increases with the increase of punch speed when the same punch head diameters are used. Furthermore, a three-dimensional finite element (FE) model of PE specimens subjected to punch load has been established to further analyze the deformation and failure behavior. A good agreement between the simulation results and the punch test data is achieved.