Study on the tensile properties of reinforced thermoplastic pipes under different internal pressures and temperatures

This work explores the tensile properties of reinforced thermoplastic pipes (RTPs) at different internal pressures and temperatures. A new mechanical model of an RTP comprising of a different number of reinforced layers has been proposed by combining the constitutive relationship between the elastoplastic material and the continuous displacement condition. On this basis, the effect of the various parameters, including the internal pressure, the winding angle, and temperature, on the tensile properties of RTPs has been investigated. In addition, tensile tests at different internal pressures have been carried out to validate the model. The results thus obtained show that the internal pressure does not affect the tensile property of the RTPs during the elastic stage. However, its influence increases significantly after the strain exceeds the elastic limit. Taking the winding angle of 37.5 degrees as a demarcation point, it is found that at winding angles smaller than this value, the total load increases with an increase in temperature, whereas at angles larger than 37.5 degrees, the total load gradually decreases with an increase in temperature. The temperature differences significantly affect the mechanical properties of the RTPs, but this effect is obvious when the inner surface temperature of the RTP exceeds its outer surface temperature.

Automated summary

This work investigates the tensile properties of reinforced thermoplastic pipes (RTPs) under different internal pressures and temperatures. A new mechanical model of RTPs is proposed, and the effect of parameters such as internal pressure, winding angle, and temperature on the tensile properties is studied. Experimental results show that internal pressure has little influence on RTPs' tensile properties during the elastic stage but significantly affects them after the elastic limit. The winding angle and temperature also have significant effects on RTPs' tensile properties.