0
Research Papers: Materials and Fabrication

Crack Growth Behavior of Pipes Made From Polyvinyl Chloride Pipe Material1

[+] Author and Article Information
Tarek M. A. A. EL-Bagory

Mechanical Design Department,
Faculty of Engineering Mataria,
Helwan University,
Cairo El-Mataria,11724, Egypt
e-mail: telbagory@yahoo.com

Maher Y. A. Younan

Associate Dean for Undergraduate Studies
School of Sciences and Engineering,
The American University in Cairo AUC,
Cairo 11835, Egypt
e-mail: myounan@aucegypt.edu

2Present address: Assistant Professor, Mechanical and Industrial Engineering Department, Engineering College, Majmaah University, P.O. Box 66, Majmaah, Riyadh, 11952, Saudi Arabia.

Contributed by the Pressure Vessel and Piping Division of ASME for publication in the JOURNAL OF PRESSURE VESSEL TECHNOLOGY. Manuscript received November 14, 2015; final manuscript received March 18, 2016; published online August 5, 2016. Assoc. Editor: David L. Rudland.

J. Pressure Vessel Technol 139(1), 011404 (Aug 05, 2016) (17 pages) Paper No: PVT-15-1255; doi: 10.1115/1.4033124 History: Received November 14, 2015; Revised March 18, 2016

The behavior of crack growth of polymeric materials is affected by several operating conditions such as crosshead speed, specimen thickness, load line, and specimen configurations, which reverse the behavior of crack from stable to unstable crack growth behavior. The main objective of the present paper is the determination of plane strain fracture toughness (KIC) for polyvinyl chloride (PVC) used in piping water transmission systems. The dimensions of the PVC pipe are outside diameter, Do = 315 mm, standard dimensions ratio, SDR = 13.23, ratio between outside to inside radii Ro/Ri = 1.179, and pipe thickness, t = 24 mm. Curved specimens are prepared from a pipe by cutting 12 mm thickness ring segments. The curved specimens are divided into two specimen configurations, namely, curved three-point bend (CTPB) and C-shaped tension (CST) specimens. All specimens are provided artificially with a precrack. CTPB specimen is further cut into five 72 deg sectors with each being centrally notched to a depth approximately a = 0.479 of the wall thickness. CST specimen configuration is characterized by the eccentricity X = 0, and 0.5 W, of the loading holes from the bore surface. The linear elastic fracture mechanics theory (LEFM) is used to predict the plane strain fracture. The tests are carried out at room temperature, Ta equal 20 °C, and different crosshead speeds of (10–500 mm/min). The numerical analysis carried out within the frame of the present work is done using the finite element program Cosmos 2.6. Finite element method (FEM) is used to compute the stress intensity factor KQ surrounding the crack tip. The computed stress intensity factor can then be compared with that obtained by theoretical equation. The experimental fracture test results reveal that the crosshead speed has been proven to affect the mode of failure and mode of fracture. At lower crosshead speeds, the mode of failure is ductile, while at higher crosshead speeds, it is brittle. The specimen configuration also affects the fracture toughness. CST specimens show higher fracture toughness in the case of pin loading location X = 0.5W than X = 0 by about (12%). The transitional crosshead speed is affected by specimen geometry. CST specimens (CST) at X = 0 and 0.5W have higher transitional crosshead speed compared with the CTPB specimen configuration.

Copyright © 2017 by ASME
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Fig. 1

CST specimen according to Ref. [14]. (a) X/W = 0.5 and (b) X/W = 0.

Grahic Jump Location
Fig. 2

Configurations of CTPB specimen according to Ref. [15]

Grahic Jump Location
Fig. 3

Crack geometry and razor blade configurations

Grahic Jump Location
Fig. 4

Schematic illustration of double cantilever clip-in displacement gauge [14]

Grahic Jump Location
Fig. 5

Determination of P5, and PQ [15]

Grahic Jump Location
Fig. 6

Measuring system used to determine KIC

Grahic Jump Location
Fig. 8

(a) Reaction force for (CTPB) specimen and (b) force analysis for (CTPB) specimen at roller pin

Grahic Jump Location
Fig. 9

(a) Initial finite element mesh for (CTPB) specimen, (b) detail (A) load application node, (c) detail (B) reaction force node, and (d) detail (C) singularity elements 1201 and 1221

Grahic Jump Location
Fig. 10

(a) Finite element mesh for (CTPB) specimen after shift, (b) detail (A) load application node shifted in Y-direction, (c) detail (B) reaction force node, and (d) detail (C) location of singularity elements 1201, and 1221 after shifting nodes in Y-direction

Grahic Jump Location
Fig. 11

Load–COD for (CST) 12 mm thick specimen, X = 0, at crosshead speed (10–500 mm/min)

Grahic Jump Location
Fig. 12

Fracture toughness versus crosshead speed for (CST) 12 mm thick specimen, X = 0 at crosshead speed (10–500 mm/min)

Grahic Jump Location
Fig. 13

Fracture configuration at crosshead speeds from (10–500 mm/min) for (CST) 12 mm thick specimen and X = 0

Grahic Jump Location
Fig. 14

Load–COD for (CST) 12 mm thick specimen, X = 0.5W, at crosshead speed (10–500 mm/min)

Grahic Jump Location
Fig. 15

Fracture toughness versus crosshead speed for (CST) 12 mm thick specimen, X = 0.5W at crosshead speed (10–500 mm/min)

Grahic Jump Location
Fig. 16

Fracture configuration at crosshead speeds from (10–500 mm/min) for (CST) 12 mm thick specimen, and X = 0.5W

Grahic Jump Location
Fig. 17

Load–COD for (CTPB) 12 mm thick specimen, at crosshead speed (50–500 mm/min)

Grahic Jump Location
Fig. 18

Fracture toughness versus crosshead speed for (CTPB) 12 mm thick specimen, at variable crosshead speed

Grahic Jump Location
Fig. 19

Fracture configuration at crosshead speeds from (10–500 mm/min) for (CTPB) 12 mm thick specimen. (a) VC,H = 10 mm/min, (b) VC,H = 40 mm/min, (c) VC,H = 50 mm/min, (d) VC,H = 60 mm/min, (e) VC,H = 70 mm/min, (f) VC,H = 100 mm/min, (g) VC,H = 200 mm/min, (h) VC,H = 300 mm/min, (i) VC,H = 400 mm/min, and (j) VC,H = 500 mm/min.

Grahic Jump Location
Fig. 20

Fracture toughness versus specimen geometry

Grahic Jump Location
Fig. 21

COD at PQ versus crosshead speed for CST at (X = 0.5W and x = 0) and CTPB specimen

Grahic Jump Location
Fig. 22

Fracture toughness versus crosshead speed for CST at (X = 0.5W and X = 0) and CTPB specimen

Grahic Jump Location
Fig. 23

Displacement chart in X-direction for (CTPB) specimen

Grahic Jump Location
Fig. 24

(a) Stress chart in X-direction for (CTPB) specimen and (b) detail (A) magnified stress chart at crack tip

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In