High Density Polyethylene Pipe Research Articles

The Extent of Damage Identification Method Using Extrusion Machine Overall Equipment Effectiveness (OEE) in PT. XYZ

PT. XYZ was a company that has been producing many different type of a pipe, the PVC (Poly Vinyl Chlorida) pipe, the HDPE (High Density Polyethylene) pipe and the gutters pipe that used for clean water irrigation, the pipe installation of housing complex, the industrial waste disposal, for reservoirs and telecommunication. The process of making a pipe is often hampered on an extrusive engine because it used during 24 hours a day and the maintenance schedule of the machine has not been applied regularly. We need to do identification about the damages of exstrusive machine with a Total Productive Maintenance using the Overall Equipments Effectiveness (OEE) method. From the research, it can be seen that the set up time to an extrusive machine still took a long time and the production volume of the machine was still low. The effectiveness of the performance from extrusive machine also have not been able to achieve the OEE's standard that was 88 % .

Fault Identification in Pipeline System Using Normalized Hilbert Huang Transform and Automatic Selection of Intrinsic Mode Function

Pressure transient analysis has been widely used to monitor the condition of pipelines and its assessment in water distribution systems. This is a low-cost nonintrusive technique with the ability to locate uncertainties (leak, pipe fitting, blockage) at a greater distance from the measurement point. In this research, Normalised Hilbert Huang Transform (NHHT) is used as the method to analyse the pressure transient signal. However, this method has difficulty in selecting the suitable intrinsic mode function (IMF) for the advance data analysing. As an alternative, Integrated Kurtosis-based Algorithm for z-filter Technique (Ikaz), which allows automatic selection of intrinsic mode function (IMF) been used to substitute the NHHT limitation in this study. The analysis is conducted on a 67.9-meter Medium High-Density PolyEthylene (MDPE) pipe installed with single artificial leak simulator at a water pressure in the range of 1-4 bar.

Procurement Assessment of High-Density Polyethylene Pipe in Department of Water Supply and Sewerage, Nepal

Procurement Assessment of High-Density Polyethylene Pipe in Department of Water Supply and Sewerage, Nepal

Thermo-physical and mechanical characteristics of sand-based lightweight composite mortars with recycled high-density polyethylene (HDPE)

Today, a large number of research projects are concerned with the recycling of plastic waste to be reused in the field of construction. This work, which is part of a research programme, focuses on the valorization of plastic waste from high density polyethylene (HDPE) pipes, to be used as aggregates. The HDPE aggregates were used as partial replacements of natural sand at 0, 15, 30, 45 and 60%, for the same volume. Only one particle size of the HDPE aggregates was used in each composition of the lightweight composite mortars (LWCM). Prismatic specimens 4 × 4 × 16 cm3 were prepared with a ratio W/C = 0.5. The density of the composite mortars was measured in the fresh and cured states. The compressive and flexural strengths, the thermo-physical characteristics as well as the ultrasonic pulse velocity (UPV) and the dynamic modulus of elasticity (Ed) were also investigated. In addition, composite mortars were analysed using a Scanning Electronic Microscope (SEM). Laboratory tests revealed encouraging results. Compared to the normal composite mortar (NMC), outcomes showed that composite mortar with 60% HDPE aggregates (LWCM60) increased ductility and reduced by 73% the dynamic modulus of elasticity. Analyses using SEM indicated that HDPE aggregates exhibited low adhesion to the cementitious matrix and mortars with higher HDPE rates improved the energy performance of composite mortars (LWCM).

Protection of Buried Pipe under Repeated Loading by Geocell Reinforcement

With increase in cities’ population and development of urbane life, passing buried pipelines near ground’s surface is inevitable in urban areas, roads, subways and highways. This paper presents the results of three-dimensional full scale model tests on high-density polyethylene (HDPE) pipe with diameter of 250 mm in geocell reinforced soil, subjected to repeated loading to simulate the vehicle loads. The effect of geocell’s pocket size (55*55 mm and 110*110 mm) and embedment depth of buried pipe (1.5 and 2 times pipe diameter) in improving the behaviour of buried pipes was investigated. The geocell’s height of 100 mm was used in all tests. The repeated load of 800 kPa was applied on circular loading plate with diameter of 250 mm. The results show that the pipe displacement, soil surface settlement and transferred pressure on the pipe’s crown has been influenced significantly upon the use of geocells. For example, the vertical diametric strain (VDS) and soil surface settlement (SSS), in a way that using a geocell with pocket size of 110*110 mm reduces by 27% and 43%, respectively, compared with the unreinforced one. Meanwhile, by increasing buried depth of pipe from 1.5D to 2D, the use of geocell of 110*110 mm delivers about 50% reduction in SSS and VDS, compared with the unreinforced soil.

Identifying mechanically induced chemical changes to vintage grade high density polyethylene pipes during squeeze-off

Squeeze-off is widely used within the gas industry for temporary interruptions to supply, both when extending and repairing the polyethylene (PE) pipe network. Over the years a number of pipe failures, have been attributed to damage caused at the squeeze-off location, often linked to non-standard squeeze-off practices. The purpose of this paper is to examine PE pipes that have been squeezed in the laboratory under ASTM and non-ASTM standard conditions to determine if any changes to the PE structure can be measured. Changes in the PE due to squeeze-off was measured by FTIR at the squeeze-off ear. The carbonyl index (CI), a measure of polymer degradation, was calculated for the various squeeze-off conditions and it was found that over-compression of the PE pipe caused the greatest amount of damage to the pipe and that is directly linked to the integrity of the pipe prior to being squeezed-off.

Comparison of viscoelastic models with a different number of parameters for transient simulations

AbstractThe numerical and analytical models used for transient simulations, and hence for the pressurized pipe system diagnosis, require the definition of a rheological component related to the pipe material. The introduction and the following widespread use of polymeric material pipes, characterized by a viscoelastic behavior, increased the complexity and the number of parameters involved in this component with respect to metallic materials. Furthermore, since tests on specimens are not reliable, a calibration procedure based on transient test is required to estimate the viscoelastic parameters. In this paper, the trade-off between viscoelastic component accuracy and simplicity is explored, based on the Akaike criterion. Several aspects of the calibration procedure are also examined, such as the use of a frequency domain numerical model and of different standard optimization algorithms. The procedure is tested on synthetic data and then it is applied to experimental data, acquired during transients on a high density polyethylene pipe. The results show that the best model among those used for the considered system implements the series of a spring with three Kelvin–Voigt elements.

Pipe leak diagnostic using high frequency piezoelectric pressure sensor and automatic selection of intrinsic mode function

In a recent study, the analysis of pressure transient signals could be seen as an accurate and low-cost method for leak and feature detection in water distribution systems. Transient phenomena occurs due to sudden changes in the fluid’s propagation in pipelines system caused by rapid pressure and flow fluctuation due to events such as closing and opening valves rapidly or through pump failure. In this paper, the feasibility of the Hilbert-Huang transform (HHT) method/technique in analysing the pressure transient signals in presented and discussed. HHT is a way to decompose a signal into intrinsic mode functions (IMF). However, the advantage of HHT is its difficulty in selecting the suitable IMF for the next data postprocessing method which is Hilbert Transform (HT). This paper reveals that utilizing the application of an integrated kurtosis-based algorithm for a z-filter technique (I-Kaz) to kurtosis ratio (I-Kaz-Kurtosis) allows/contributes to/leads to automatic selection of the IMF that should be used. This technique is demonstrated on a 57.90-meter medium high-density polyethylene (MDPE) pipe installed with a single artificial leak. The analysis results using the I-Kaz-kurtosis ratio revealed/confirmed that the method can be used as an automatic selection of the IMF although the noise level ratio of the signal is low. Therefore, the I-Kaz-kurtosis ratio method is recommended as a means to implement an automatic selection technique of the IMF for HHT analysis.

Combined Use of Jute Geotextile-EPS Geofoam to Protect Flexible Buried Pipes: Experimental and Numerical Studies

This paper addresses the results of the experimental and numerical studies conducted on 4.2 mm thickness and 110 mm diameter high-density polyethylene (HDPE) pipes buried in fly ash material overlying stone dust beds. The model tests were performed using single and double layers of expanded polystyrene (EPS) geofoam as compressible inclusions. In addition to that, jute geotextile was used as a reinforcement for the infill fly ash along with EPS geofoam inclusion to obtain induced trench condition. The test beds were subjected to loading on the fly ash surface with the help of a rigid steel plate to simulate as a strip footing in different embedment depths of the pipe (1–3 times pipe diameter). The test results revealed that the pressure and strain values in the pipe reduced significantly in the presence of EPS geofoam and jute geotextile related to the location of the pipe. In the case of double layers of EPS geofoam could induce reduction of the pressure up to 87.2% and strain about 63.5% respectively depending on the density and width of EPS geofoam. Whereas, at the same burial depth, in the presence of jute geotextile together with EPS geofoam can be reduced up to 93.8 and 73.4% for pressure and strain respectively depending on EPS geofoam density and number of reinforcement. Moreover, the jute geotextile-EPS geofoam combination of model test results were validated with finite element program. A good agreement was observed on pressure-settlement response and pipe strain between experimental and numerical investigations. The numerical studies show that the jute geotextile distributes stresses in the lateral direction and then the stresses on the pipe significantly reduced.

Using developed creep constitutive model for optimum design of HDPE pipes

Unlike metal pipes, high density polyethylene (HDPE) pipes are not susceptible to erosion and corrosion. However, the most important mechanical feature of the HDPE pipes is that this material creeps even at room temperature. Therefore, it is essential to study the creep behavior of this material in order to develop a model. In this paper, creep behavior of HDPE at different temperature and stress levels has been experimentally studied to obtain the creep constitutive parameters of the material. These parameters are used to predict the creep behavior of different structures such as HDPE pipes. For this purpose, a number of specimens have been machined from industrial manufactured pipe walls. Uniaxial creep tests have been carried out and creep strain curves with time for each test were recorded. Then, a constitutive model is proposed for HDPE based on the experimental data and optimization methods. The results of this model have been compared with the test data and good agreement is observed. The developed constitutive model and reference stress method (RSM) were used to produce graphs which provide optimum creep lifetime and design conditions for HDPE pipes that are subjected to combined internal pressure and rotation. These graphs can facilitate the design process of HDPE pipes.

Numerical Modeling of Installation of Steel-Reinforced High-Density Polyethylene Pipes in Soil

AbstractSteel-reinforced high-density polyethylene (SRHDPE) pipe uses steel ribs to carry loads and plastic cover to prevent the steel ribs from corrosion so that it overcomes the disadvantages of ...

Stress Intensity Factor K I and T-Stress Determination in HDPE Material

For the characterization of high-density polyethylene (HDPE) pipes according to the operating conditions, the Nol ring test is an adequate method to rapidly and inexpensively determine the mechanical properties with good effectiveness. In this work, Nol ring tests will be carried out on HDPE material with different crack depth ratios. Based on these results, the brittle fracture of HDPE will be studied and a new experimental technique for measuring stress intensity factor (SIF) and T-stress under mode I conditions is developed. The formulation of the normal strains, close to the crack tip, is given using the first five terms of the generalized Westergaard formulation. Then, in a second step, these formulations are applied to analytically determine the optimum locations for the rectangular rosette to eliminate the errors due to higher order terms of the asymptotic expansion.

Earth pressures on the trenched HDPE pipes in fine-grained soils during construction phase: Full-scale field trial and finite element modeling

Abstract High density polyethylene (HDPE) pipes have been widely used in civil engineering applications. The peaking deflection of the buried HDPE pipes caused by the compaction of the pipe sidefill during the construction phase is not considered in the current pipe design standards. Fine-grained soil may be an alternative backfill when relative high quality coarse-grained soil is absent in-situ or difficult to transport from a long-distance away in urban areas. The effect of construction on the earth pressures around HDPE pipes buried in fine-grained backfills has not been well understood. In this study, a full-scale field trial was undertaken to monitor the earth pressures acting on HDPE pipes buried in fine-grained soils during the construction phase. Three HDPE pipes with norminal diameters of 600, 600, and 300 mm, respectively, were used in the field trial. Numerical modeling which was able to consider the peaking deflection was conducted to investigate the effects of pipe diameter, pipe stiffness, degree of compaction of the backfill, and trench width on the earth pressures acting on the pipes. The measured earth pressures and deflection were utilized to verify the effectiveness of numerical modeling procedures. The finite element analyses indicated that the trench width had a more significant effect on the earth pressures, as compared to other factors. Two empirical equations were proposed, based on the numerical results, for predicting the earth pressures at the top and the springline of the pipes during the construction phase. The validity of the proposed equations was evaluated using the field data obtained from both this study and published studies.

Performance of buried HDPE pipes – part II: total deflection of the pipe

Total deflection of buried thermoplastic pipes is extensively studied in previous work as it is a service limit state specified in design standards. In this paper, two-dimensional finite-element modeling is conducted to investigate the total deflection of buried high-density polyethylene (HDPE) pipes with a special consideration of the peaking behavior. The finite-element modeling method is evaluated using the data measured in a field trial which is presented in Part I. Parametric study are conducted. It is shown that the relative flexure stiffness, the type of compactor and the unit weight of soil cover have significant effects on the total deflection of the pipe. Based on analyses of the finite-element simulation results and experimental data, two empirical formulas with five parameters are proposed to describe the total deflection of HDPE pipes in both the vertical and horizontal directions. A comprehensive comparison is made between the calculated deflections made using the proposed equations and some existing methods and the measured data from published papers. It is seen that the proposed method significantly improves the accuracy of existing methods, and it also has advantages over existing methods because it has far fewer parameters and more convenient parameter determination.

Performance of buried HDPE pipes – part I: peaking deflection during initial backfilling process

Peaking deflection caused by compacting the sidefill, referred to as the maximum change of the pipe diameter divided by the undeformed diameter, is an important parameter in the design and safety check of buried pipelines. However, quantitative equations on the deflection useful for engineering practice are very limited. In this paper, a two-dimensional finite element analysis is used to investigate the peaking deflection of high-density polyethylene (HDPE) pipes. In the analyses, the pipe–soil interaction is rationally modeled. A field trial is conducted and the finite-element modeling is evaluated by using the data measured in the field test. Parametric studies are also conducted to investigate the effects of pipe diameter, pipe stiffness, soil modulus, trench width, and compactor type on the peaking deflection of buried HDPE pipes. A new estimating tool is developed that considers the major influencing factors: pipe diameter, pipe stiffness, soil modulus, and compactor type (vibratory plate or rammer) to predict the peaking deflection of HDPE pipes, and the proposed method is finally verified by data reported in published studies. The comparison of the calculated and measured peaking deflections demonstrates a reasonably good prediction of the peaking deflection.

Analysis of ground-source heat pumps in north-of-England homes

The performance of ground-source heat pumps (GSHPs) for domestic use is an increasing area of study in the UK. This paper examines the thermal performance of three bespoke shallow horizontal GSHPs installed in newly built residential houses in northern England as compared with a control house fitted with a standard gas boiler. A 350 m high-density polyethylene pipe with an external diameter of 40 mm was used for each house as a heat pump loop. The study investigated the performance of a single-loop horizontal ground heat exchanger against a double loop. It also investigated rainfall effects on heat extraction by comparing a system with an infiltration trench connected to roof drainage against a system without an infiltration trench above the ground loops. Parameters were monitored for a full year from October 2013 to September 2014. Using the double-loop exchanger has shown an enhanced performance of up to 20% compared with a single loop. The infiltration trench is found to improve performance of the heat pumps; the double loop with an infiltration trench had a coefficient of performance 5% higher than a double loop without a trench.

Modeling of cohesive fracture interacting with a stationary capillary fluid

Understanding cohesive fracture interacting with a stationary capillary fluid is essential for fracture mechanics based analysis and design of many quasibrittle structures in contact with fluids. In this study, an equivalent linear elastic fracture mechanics (LEFM) model is used to determine the equilibrium state for a cohesive crack partially filled with a capillary fluid. The model is shown to deliver predictions similar to the cohesive zone model (CZM) at a much lower computational cost. The equivalent LEFM model is applied to determine the instantaneous failure pressure of high-density polyethylene (HDPE) pipes as well as the wetting zone size for modeling the stress corrosion cracking of HDPE pipes.

Comparison of Parent and Butt-Fusion Material Properties of Unimodal High-Density Polyethylene

The U.S. nuclear power industry is seeking U.S. Nuclear Regulatory Commission (USNRC) approval to use high-density polyethylene (HDPE) in safety-related applications. The USNRC had granted approval for the use of HDPE for safety-related service water applications, with limitations, to Catawba (Duke Energy Corp., Catawba, SC) and Callaway (Union Electric Co., Callaway, MO) based on separate relief requests submitted by the licensees. The nuclear industry continues to show increasing interest in utilizing HDPE in safety-related piping systems. In order to evaluate and maintain the structural integrity of HDPE pipes, the material properties and the fracture resistance behavior must be fully characterized. Although there has been extensive work on material property development of HDPE, most of the investigations have been focused on the parent (base) material. Hence, the material property and fracture resistance behavior of the butt-fusion region have not been comprehensively investigated. In this paper, tensile, dynamic mechanical analysis (DMA), and slow crack growth (SCG) tests were performed for unimodal PE 4710 HDPE material. Specimens were machined from both parent piping material and butt-fusion regions. The test results indicate that the tensile and DMA properties show no significant differences between parent and butt-fusion joint materials. However, in terms of SCG resistance, the time to failure for butt-fusion joint material was an order of magnitude lower than that of the parent material.

Deformation of Buried HDPE Pipes Subjected to Differential Soil Settlement

Buried high density polyethylene (HDPE) pipes are often damaged by differential soil settlement. The deformation of the buried pipe as a critical response is widely investigated in previous studies. In this study, a series of full-scale model tests are undertaken to study the deformation of buried HDPE pipes subjected to differential soil settlement. Three HDPE double-wall corrugated pipes with diameter of 300 and 400 mm are installed in the model box at the burial depth of 0.6 m and 0.9 m. Three cross-sections in axial direction of the pipe are instrumented by custom-made settlement plates and strain gauges to monitor the structural responses of the pipe. The results demonstrate that the vertical deflection distribution of HDPE pipes in the longitudinal direction agrees well with the modified Gaussian curve function. The linear regression equations are proposed to correlate the maximum vertical displacement of the pipes with the settlements of the soil surface.

A study of the micro-mechanical properties of butt fusion-welded joints in HDPE pipes using the nanoindentation technique

High-density polyethylene (HDPE) pipes are being used increasingly in many traditional industries as an alternative to metallic pipes. The weakest part of every pipe system is the welded joint. A number of standards are available that define the welding procedure for butt fusion welding of HDPE pipes. However, they define very different values for welding pressure and temperature, for the exact same materials. HDPE PE100 180 mm SDR11 pipes were welded using various standard and non-standard welding procedures. The ranges of welding parameters chosen were expected to produce detectable changes in the size of the weld regions and their micro-mechanical properties. The micro-mechanical properties across butt fusion welds were characterised using the nanoindentation technique. The indentations were spaced at 100 μm at the mid-wall position of the welded joint in a grid of 60 columns by 3 rows. The melt zone (MZ) showed a distinct drop in material properties consistently across all welding procedures. Nanoindentation also revealed the presence of a heat-affected zone (HAZ) surrounding the MZ, characterised by a gradual increase in material properties from that of the parent material to the boundary with the MZ. The size of the MZ measured using nanoindentation was correlated with transmission light microscopy images of microtomed slices.