Numerical and experimental study of mechanical properties and hydrostatic behavior of PVC-O material for drinking water pipes

Dilshad Azad Mohammed; Mohammedtaher M. Saeed Mulapeer

doi:10.21271/ZJPAS.33.2.9

Authors

Dilshad Azad Mohammed Department of Refrigeration & Air conditioning, Kalar Technical Institute, Sulaimani Polytechnic University, Sulaimani, Iraq
Mohammedtaher M. Saeed Mulapeer Department of Mechanical & Mechatronics ,College of Engineering, Salahaddin University -Erbil, Iraq

DOI:

https://doi.org/10.21271/ZJPAS.33.2.9

Keywords:

Oriented Polyvinyl Chloride; Hoop stress; Hydrostatic strength; Von Mises yield criteria; Finite element analysis.

Abstract

This study investigates the mechanical properties for oriented polyvinyl chloride PVC-O material from three different directions of stress application. A PVC-O 500 pipe material has been studied in terms of mechanical properties in three different directions (0^o, 45^o, 90^o). Tensile strength at yield and percent elongation at fracture has been determined in all three directions. Two types of end caps (A and B) have been used to evaluate the pipe's hydrostatic strength. Results showed that molecular orientation has a significant impact on the pipe strength and ductility in different directions. Increasing the molecular orientation in the direction of the hoop (90^o direction), the strength increased to 91 MPa compared with 0^o and 45^o direction, which were 49 MPa and 61 MPa, respectively. Results showed that the percentage of elongations was 200%, 76 %, and 61% for 0^o, 45^o, and 90^o directions, respectively. The burst pressure for type A and B end caps was 6.22 MPa. Finite element analysis by SolidWorks 2018 simulation has been employed; the FEA has showed a good agreement with experimental results with a maximum difference of 5.16%. The FE results also showed that end caps affect stress distribution around the pipe during the hydrostatic test specially when using type B end caps. It's also concluded that both types of end caps cause stress concentration near the edges of the caps.

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Figure captions:

Figure 1. Molecular orientation process (PromainsTOM®, 2012).

Figure 2. Tensile testing procedures.

Figure 3. Failure shape during the hydrostatic pressure test.

Figure 4. Finite element mesh of PVC-O pipe with end caps

Figure 5. Stress-Strain diagram of (PVC-O) tested at (0°, 45°, 90°).

Figure 6. Variation of tensile strength at yield and Percent elongation as a function of test direction and molecular orientation.

Figure (7). Finite element analysis of stress distribution during the hydrostatic test at 6.2MPa internal pressure.

Figure (8). Distribution of longitudinal stress along the pipe (0o- direction).

Figure (9). Distribution of Stress at an angle of 45° along the pipe.

Figure (10). Distribution of circumferential (hoop) stress along the pipe (90o-direction).