Depending on the norm which is tested and the application purpose of the pipes, different-sized test stripes are tested to determine the ring stiffness.
The 6 meter high special testing machine S-XL 600kN has been developed especially for the testing of glass fibre-reinforced plastic pipes. These pipes are used, for example, as drinking water lines, waste water lines, irrigation or drainage systems. While the pipes are installed, they are exposed to high pressure loads. Therefore, the determination of the mechanical properties is of crucial importance. This takes place by testing the nominal ring stiffness.
The nominal ring stiffness describes the strength behaviour of plastic pipes. The special testing machine is used to test pipe stripes approx. 300mm wide and with a wall thickness of 150mm and a diameter of up to 4200mm. The non-destructive elasticity test takes place in two steps. In the compression test, the plastic pipe is deformed in vertical direction with a distributed load firstly until 2% and subsequently until 5%. The ring deformation on the inside diameter of plastic pipes with a preset ring stiffness must not exceed a specified value. The test is carried out at room temperature.