Effect of temperature on tensile properties of HDPE pipe material

2006 ◽  
Vol 35 (5) ◽  
pp. 226-230 ◽  
Author(s):  
N. Merah ◽  
F. Saghir ◽  
Z. Khan ◽  
A. Bazoune
Keyword(s):  
Tensile Properties ◽  
Effect Of Temperature ◽  
Pipe Material ◽  
Hdpe Pipe

Critical Flaw Size Evaluation in Butt-Fusion Joints of HDPE Pipes

2014 ◽  
Author(s):  
S. Kalyanam ◽  
P. Krishnaswamy ◽  
E. M. Focht ◽  
D.-J. Shim ◽  
F. W. Brust ◽  
...  
Keyword(s):  
Structural Integrity ◽  
Nuclear Industry ◽  
Flaw Size ◽  
Fusion Process ◽  
Pipe Material ◽  
Element Analysis ◽  
Hdpe Pipe ◽  
Asme Code ◽  
Critical Flaw ◽  
Pipe Joints

The integrity of high density polyethylene (HDPE) piping and fusion joints are a topic of interest to the nuclear industry, regulators, ASME code, and the plastics pipe industry. The ASME Code Case N-755-1 has been approved and addresses the use of HDPE in safety related applications. Over the last few years some of the concerns identified with the parent HDPE pipe material and the fusion joints have been addressed while others are still being resolved. One such unresolved concern is the effect of the fusion process on the integrity of the joint, specifically, the introduction of flaws during the fusion process. The potential impact of flaws in the fusion joint on the service life of the HDPE piping is being evaluated. The current study calculates stress intensity factors (SIF) for circumferential flaws and uses them to evaluate the potential structural integrity of HDPE fusion joints in pipes. The recent API 579-1/ASME FFS-1 standard provides SIF (KI) solutions to various semi-elliptical and full-circumferential (360°) surface cracks/flaws on the outer surface (OD) and the inner surface (ID). The API 579-1/ASME FFS-1 standard SIF tables and finite element analysis (FEA) of selected cases were used to develop simplified SIF relations for full-circumferential surface flaws that can be used for plastic pipes with diameters ranging from 101.6 mm (4 inch) through 914.4 mm (36 inch) and dimensional ratios (DRs) from 7 through 13. Further, the SIF of embedded flaws akin to lack-of-fusion regions was evaluated. The results from this study serve as precursors to understanding and advancing experimental methods to address important issues related to the critical tolerable flaw size in the butt-fusion joint material and were utilized to select the specimen tests and hydrostatic pipe tests used to evaluate various joining processes. Further, they will help with understanding the essential variables that control the long-term component integrity and structural performance of HDPE pipe joints in ASME Class 3 nuclear piping.

Slow Crack Growth Resistance of Parent and Joint Materials From PE4710 Piping for Safety-Related Nuclear Power Plant Piping

2011 ◽  
Author(s):  
S. Kalyanam ◽  
D.-J. Shim ◽  
P. Krishnaswamy ◽  
Y. Hioe
Keyword(s):  
Crack Growth ◽  
Nuclear Power ◽  
Power Plants ◽  
Slow Crack Growth ◽  
Nuclear Industry ◽  
Pipe Material ◽  
Service Water ◽  
Hdpe Pipe ◽  
Pipe Materials ◽  
Hdpe Pipes

HDPE pipes are considered by the nuclear industry as a potential replacement option to currently employed metallic piping for service-water applications. The pipes operate under high temperatures and pressures. Hence HDPE pipes are being evaluated from perspective of design, operation, and service life requirements before routine installation in nuclear power plants. Various articles of the ASME Code Case N-755 consider the different aspects related to material performance, design, fabrication, and examination of HDPE materials. Amongst them, the material resistance (part of Article 2000) to the slow crack growth (SCG) from flaws/cracks present in HDPE pipe materials is an important concern. Experimental investigations have revealed that there is a marked difference (almost three orders less) in the time to failure when the notch/flaw is in the butt-fusion joint, as opposed to when the notch/flaw is located in the parent HDPE material. As part of ongoing studies, the material resistance to SCG was investigated earlier for unimodal materials. The current study investigated the SCG in parent and butt-fusion joint materials of bimodal HDPE (PE4710) pipe materials acquired from two different manufacturers. The various stages of the specimen deformation and failure during the creep test are characterized. Detailed photographs of the specimen side-surface were used to monitor the specimen damage accumulation and SCG. The SCG was tested using a large specimen (large creep frame) as well as using a smaller size specimen (PENT frame) and the results were compared. Further, the effect of polymer orientation or microstructure in the bimodal HDPE pipe on the SCG was studied using specimens with axial and circumferential notch orientations in the parent pipe material.

scholarly journals EXPERIMENTAL FINDING OF FRACTURE TOUGHNESS CHARACTERISTICS AND THEORETICAL MODELING OF CRACK PROPAGATION PROCESSES IN CARBON FIBER SAMPLES UNDER CONDITIONS OF ADDITIVE PRODUCTION

2019 ◽  
Vol 16 (33) ◽  
pp. 325-336
Author(s):  
V. N. DOBRYANSKIY ◽  
L. N. RABINSKIY ◽  
O. V. TUSHAVINA
Keyword(s):  
Fracture Toughness ◽  
Carbon Fiber ◽  
Crack Resistance ◽  
Tensile Properties ◽  
Practical Importance ◽  
Effect Of Temperature ◽  
Zone Model ◽  
Cohesive Elements ◽  
Damage Development ◽  
Mechanical Tensile

The relevance of the problem stated in this article is that the development of aerospace technology increased the demand for good quality materials. An important issue is ensuring durability in conditions of longterm loads and in conditions of damage development. One of the criteria that ensure the toughness of the material is crack resistance. The aim of the work is to study the interlayer crack resistance (fracture toughness) under loading under conditions of separation and transverse shear, interlayer strength, as well as the effect of temperature on interlayer strength, mechanical tensile properties. A comparison of the values of interlayer crack resistance GIС (separation) and GIIС (shear) and of mechanical tensile properties and interlayer strength of carbon fiber samples is made. The main methods for studying this problem were the short-beam method, the DCB method, the ENF method. The results of the experimental data were compared with modeling the processes of the appearance and development of cracks in the finite element complexes ABAQUS and Ansys based on the VVCT models, cohesive elements. Deviations from the experiment were found and conclusions were drawn that the point of application of the load had to be shifted from the edge of the sample, which will reduce the initial separation and increase the stiffness of the sample. Due to the fact that the cohesion zone model is very sensitive to input parameters, it is necessary to know many parameters and take into account a large number of factors. The practical importance of this work is to show how to use the VCCT model to obtain the critical load of the germination of the first crack. The research technique can be used for further experiments, including simulation further stratification with low inaccuracy.

Combined Effect of Temperature and Soil Load on Buried HDPE Pipe

2012 ◽  
Vol 452-453 ◽  
pp. 1169-1173
Author(s):  
Zheng Li ◽  
Hong Wu Zhu ◽  
Xiang Ling Kong ◽  
Abdennour Seibi
Keyword(s):  
Combined Effect ◽  
Effect Of Temperature ◽  
Hdpe Pipe ◽  
Soil Load

scholarly journals Study on Tensile Properties of CFRP Plates under Elevated Temperature Exposure

Materials ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 1995 ◽  
Author(s):  
Yongxin Yang ◽  
Yanju Jiang ◽  
Hongjun Liang ◽  
Xiaosan Yin ◽  
Yue Huang
Keyword(s):  
Tensile Strength ◽  
Elastic Modulus ◽  
Elevated Temperature ◽  
Tensile Properties ◽  
Failure Mode ◽  
Elevated Temperatures ◽  
Strain Curve ◽  
Effect Of Temperature ◽  
Temperature Exposure ◽  
The Impact

Elevated temperature exposure has a negative effect on the performance of the matrix resin in Carbon Fiber Reinforced Plastics (CFRP) plates, whereas limited quantitative research focuses on the deteriorations. Therefore, 30 CFRP specimens were designed and tested under elevated temperatures (10, 30, 50, 70, and 90 °C) to explore the degradations in tensile properties. The effect of temperature on the failure mode, stress-strain curve, tensile strength, elastic modulus and elongation of CFRP plates were investigated. The results showed that elevated temperature exposure significantly changed the failure characteristics. When the exposed temperature increased from 10 °C to 90 °C, the failure mode changed from the global factures in the whole CFRP plate to the successive fractures in carbon fibers. Moreover, with temperatures increasing, tensile strength and elongation of CFRP plates decreases gradually while the elastic modulus shows negligible change. Finally, the results of One-Way Analysis of Variance (ANOVA) show that the degradation of the tensile strength of CFRP plates was due to the impact of elevated temperature exposure, rather than the test error.

Experimental Study on Post Fire Tensile Properties of Reinforcing Rebars Connected by Grout-Filled Splice Sleeves

2018 ◽  
Vol 773 ◽  
pp. 305-310
Author(s):  
Yong Jun Liu ◽  
Qing Hong Zeng ◽  
Hong Ru Liu ◽  
Shuo Xun Wang
Keyword(s):  
Tensile Properties ◽  
Ultimate Load ◽  
Reference Group ◽  
Testing Machine ◽  
Effect Of Temperature ◽  
Reinforcing Bars ◽  
Load Bearing ◽  
Standard Fire ◽  
Structural Behaviors ◽  
Steel Rebars

This paper presents some experimental results of tensile properties of reinforcing bars spliced by grout-filled coupling sleeves after exposed to fires to identify the effect of temperature histories on tensile properties of spliced reinforcing bars, which provide a useful base for assessing structural behaviors of precast reinforced concrete buildings damaged by fires. A spliced rebar system investigated in this paper consists of two equal-diameter steel reinforcing bars with 25mm diameter and a straight coupling sleeve with 55mm outer and 42mm inner diameters. As a result, the thickness of grout between internal steel bars and outer sleeves are 8.5mm. Five test specimens are manufactured in identical technology and divided into three groups. First group is reference group consist of just one specimen which is not exposed to fire. Second and third groups consist of two specimens that are exposed to ISO 834 standard fire in furnace for 15 and 25 minutes respectively. The temperature-time curves of grout between rebars and sleeves are measured via thermocouples embedded in grout. Subsequently, a universal testing machine is used to test the ultimate load bearing capacities of five specimens. Test results demonstrate that ultimate load bearing capacities of steel rebars spliced by grout-filled sleeves are considerably reduced due to fire damaged grout.

scholarly journals Investigating and Optimizing the Process Variables Related to the Tensile Properties of Short Jute Fiber Reinforced with Polypropylene Composite Board

2012 ◽  
Vol 7 (4) ◽  
pp. 155892501200700 ◽  
Author(s):  
Saravanan Kannappan ◽  
Bhaarathi Dhurai
Keyword(s):  
Tensile Strength ◽  
Tensile Properties ◽  
Fiber Composite ◽  
Tensile Tests ◽  
Tensile Failure ◽  
Jute Fiber ◽  
Effect Of Temperature ◽  
Composite Board ◽  
Predicted Values ◽  
Experimental Pressure

The effect of temperature, pressure, and time on the tensile strength of jute fiber composite has been studied. The process of preparing the composite specimens is discussed. The best tensile properties were observed if the composite board is manufactured using high pressure and moderate temperature. For tensile strength, the time does not play a significant role. The study identifies the principal experimental pressure variables, which have the greatest effect on the tensile strength of the composite. The composite boards were subjected to tensile tests and the fractured surfaces were observed under SEM. The SEM photomicrographs of the fractured surfaces of the composite board show diverse extents of fiber pull-outs under tensile failure. The tensile strength values are in good concurrence with predicted values and were found have a correlation coefficient of 96%.

Effect of temperature and pipe material on biofilm formation and survival of Escherichia coli in used drinking water pipes: a laboratory-based study

2006 ◽  
Vol 54 (3) ◽  
pp. 49-56 ◽  
Author(s):  
J. Silhan ◽  
C.B. Corfitzen ◽  
H.J. Albrechtsen
Keyword(s):  
Drinking Water ◽  
Biofilm Formation ◽  
Water Phase ◽  
Effect Of Temperature ◽  
Plate Count ◽  
Pipe Material ◽  
E Coli ◽  
Water Pipes ◽  
Higher Temperature ◽  
Static Conditions

Segments of used drinking water pipes of galvanised steel (GS), cross-linked polyethylene (PEX), copper pipes (Cu) or new medium-density polyethylene (PE) were investigated for the formation of biofilm and survival of E. coli in biofilm and in the water phase. Pipes were filled with water and incubated at 15 °C or 35 °C under static conditions. Biofilm formation was followed during 32, 40 and 56 (58) d. The most dense biofilm was formed on GS, reaching approximately 4.7×105 CFU/cm2 measured as heterotrophic plate count (HPC), and at the other materials the density reached 3×103 CFU/cm2 on PE and PEX and 5×101 and 5×102 CFU/cm2 on Cu pipes after 58 d at 15 °C. Biofilm HPC values were higher at 35 °C than at 15 °C, with only slightly higher values on the metals, but 100-fold higher on PE and PEX. Adenosine triphosphate (ATP) measurements confirmed the general trends observed by HPC. Higher temperature was seen to be an important factor reducing E. coli survival in the water phase in drinking water pipes. At 15 °C E. coli survived more than 4 d in GS and Cu pipes and 8 d in PE pipes, but was not detected after 48 h at 35 °C. The E. coli survived longer at both temperatures in the glass control bottles than in the drinking water pipes. Despite the obvious biofilm formation, E. coli was not detected in the biofilm at any of the investigated surfaces.

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