Study of the Effect of Temperature on the Deflection of PVC and CPVC Pipes When Subjected to Bending

(Mishari Bin Abdul Latif and a sense of bliss)

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Abstract

In the current work, the deflection of PVC and CPVC pipes when subjected to bending have been studied at room temperature (23OC), 50OC and 80OC. The test specimen was designed as a simply supported beam subjected to three point bending. The bending force was adjusted to act at the middle of the specimen. The test specimens were loaded up to a deflection equal to two times of the pipe diameter (d=26 mm). To increase the results accuracy, 4 specimens were tested at each temperature. The obtained results showed that, the plastic deformation remained approximately constant for test temperatures 23OC and 50OC but, the plastic deformation of PVC pipes is two times of that for CPVC pipes. At 80OC the plastic deformation for both PVC and CPVC increased where the deflection of PVC remained bigger than that for CPVC. To assure the accuracy of the relation between the force and the corresponding deflection, the experimental relation was compared with the theoretical one. It was found that, the experimental and theoretical relation between the load and the corresponding deflection is matching very well from the beginning up to the elastic region, which was found to be from 0 to 20 mm deflection. The relation between the load and the displacement was divided to region; the first region is the elastic region while the second region is the plastic region. The pipes stiffness (K) in the plastic loading region is 30% of that in the elastic region. The pipes stiffness decreased with small rates due to temperature change from 23OC to 50OC, while, the pipes stiffness decreased with higher rates due to temperature change from 50OC to 80 OC.
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