Pipe Joints Research Articles

An automatic defect detection and localization method using imaging geometric features for sewer pipes

Accurate longitudinal localization of defects in sewer pipes is crucial for efficient maintenance and renewal. However, traditional closed-circuit television (CCTV)-based localization methods have been inefficient and imprecise, impeding real-time inspection performance. In this paper, we firstly point out that the inaccuracy of CCTV-based localization methods stems from the oversight of monocular imaging geometry, which leads to a deviation in sewer defect localization. Then, we propose an automated framework for sewer defect detection and longitudinal localization based on a deep-learning algorithm and monocular imaging geometry. Specifically, structural defects are qualitatively analyzed to explore their intrinsic correlation with the pipe wall. Then, the imaging geometry is leveraged to establish the projection relationship between the defects and the pipe joints. The longitudinal localization correction model for structural defects is then developed using the pipe diameter as the actual size. Our experiments show that this framework enhances the mean average precision (mAP) for multi-defects by 7.2 % and achieves a theoretical mean absolute error of 0.2 m and a practical mean absolute error of 0.28 m for defect localization, surpassing current research. Finally, with the generated detection results and localization records, the proposed framework can promote the efficiency of the sewer investigation and accelerate the development of intelligent sewer systems.

Numerical investigation on failure modes and TDA-based mitigation measure of jointed rigid pipes under ground subsidence

Jointed rigid pipes are vulnerable to permanent ground deformation (PGD). Compressible and lightweight materials, such as tire-derived aggregate (TDA), geofoams and straws, can be placed around buried pipes to reduce the loads from PGD and minimize the risk of pipe failures. In this study, a calibrated three-dimensional finite element model incorporating a modified Mohr-Coulomb model for simulating the strain softening behavior of surrounding soils is employed to analyze the failure modes of jointed rigid pipes under ground subsidence with various crossing scenarios, where the fault plane intersects different positions of the pipeline. Then, the efficiency of TDA mitigation in reducing the risk of pipe failure is evaluated, considering variations in geometry, size and density of TDA zone. It is found that the most detrimental fault-pipe crossing position locates at 3/4L of the pipe barrel, where excessive bending moment can lead to longitudinal cracking. TDA mitigation mainly prevents structural failure of pipelines, while its influence on the kinematics of joints is negligible. The most pronounced loading reduction for pipelines is achieved by employing TDA with a lower degree of compaction, combined with the burial configuration of full-surrounded layout pattern of TDA.

Bending Performance of F-Type Socket Joints for Rectangular Pipe Jacking Tunnels with Longitudinal Connectors

Joints are the weakest part of rectangular pipe jacking tunnels, and the structural form of the joint is closely related to its bending resistance. In this work, the F-type socket joint of a rectangular pipe jacking tunnel is selected as the object of study. The bending mechanical properties of the joints connected by steel screws and those connected by bent bolts are compared via a three-point bending test. The results show that the two longitudinal connection joints have similar bending stiffnesses. Compared with the bent bolt connection joint, the steel screw connection joint has better toughness, and the load at which the joint enters the plastic stage and the bearing capacity are increased by 0.47 times and 1.02 times, respectively. The failure modes of the joints connected by steel screw connections and those connected by bent bolts are crushing of the concrete of the top plate and cracking of the concrete above the screw holes, respectively. When a bent bolt connection is used, the reinforcement at the screw hole should be locally strengthened, or ultrahigh-performance concrete (UHPC) should be used at the screw hole to improve the load-bearing capacity of the joint.

Influence of rotational speed on interfacial microstructure and tensile properties of friction welded Al-SS pipe joints

Influence of rotational speed on interfacial microstructure and tensile properties of friction welded Al-SS pipe joints

Stress analysis in the buried polyethylene pipes with viscoelastic behavior: a finite element study

In the current study, the stress distribution in the pipe with viscoelastic behavior in presence of different loading conditions has been investigated. In order to connect the polyethylene (PE) gas pipes, the electrofusion sockets are used. Since joints are one of the most sensitive regions of a structure, it is very important to investigate the local stresses created at the joints of PE pipes. To study the stress changes in the buried pipelines and sockets, the numerical simulation of the problem has been carried out in ANSYS software. To validate the obtained numerical findings, the maximum values of the axial and von Mises stresses in the pipe and socket were compared with the values obtained from previous research, and an acceptable overlap was achieved. In this research, the stress distribution in the PE pipes buried in the soil with and without sockets in presence of thermo-mechanical load has been studied, comprehensively. In the finite element modelling, the pipe and socket are made of PE80 and PE100 materials, respectively. The research results showed that the electrofusion sockets are able to be employed to connect PE gas pipes in hot climate regions. Additionally, the outcomes obtained from viscoelastic socket and pipes compared with the isotropic pipe. The findings demonstrated that the maximum von Misses stress in viscoelastic pipe and socket reduces 21% in comparison with linear elastic state.

Study on Low-Temperature Deposition of Diamond-like Carbon Film on the Surface of Bionic Joint Thread and Its Properties

The double-connection structure of bionic joints of mining drill pipes has solved the problem of drill drop caused by fatigue cracks. However, with low-melting-point elastic–ductile alloy filling in the bionic joint, the thread on the joint cannot be hardened by high-temperature surface hardening treatments such as quenching and nitriding, making it prone to thread gluing or excessive wear. In this paper, the feasibility of diamond-like film deposition on the surface of a bionic drill pipe thread was studied. A tungsten transition film was used to improve the thickness of the film and the interfacial bond strength between the film and the substrate. The test results show that the total thickness of the DLC film is about 3~5 μm, the roughness is less than 2 μm, the hardness of the film reaches 24.4 GPa, the friction coefficient is 0.04, and the critical load is 56 N. SEM and EDS analyses show that the tungsten film and the bionic joint thread form a metallurgical structure. The morphology of the diamond-like carbon film is uniform and dense, and there is no obvious stratification between the substrate material. The joint with a diamond-like coating treatment has a longer service life than joints receiving conventional high-temperature nitriding treatment.

Influence of Interpass Temperature on the Simulated Coarse-Grained Heat-Affected Zone of a Circumferentially Welded 2.25Cr-1Mo Steel Pipe Joint

To reduce manufacturing costs, energy companies aim to maximize the deposition rate during welding operations by increasing the interpass temperature (IT), thereby minimizing the cooling time. However, IT can significantly affect weldment performance, particularly its Charpy V-notch (CVN) impact energy (toughness). The present study investigates the effect of increasing IT beyond the limit specified by the ASME B31.3 (315 °C) on the CVN impact energy (−30 °C) of the simulated coarse-grained heat-affected zone (CGHAZ) of a 2.25Cr-1Mo steel submerged arc welded (SAW). The CGHAZ thermal cycles were obtained through finite element method simulations and physically replicated using a Gleeble machine. The increase in IT beyond the ASME-specified limit significantly reduces the CVN impact energy of the CGHAZ. However, the values obtained remained above the minimum required threshold (NORSOK M630, 42 J). The main effect of increased IT was grain coarsening. Additionally, an inverse linear relationship was observed between effective grain size (EGS) and CVN impact energy. The steel’s microstructure showed non-significant sensitivity to variations in IT within the studied range. These findings suggest that, under the conditions studied, increasing IT could be a viable option for optimizing production by reducing welding time and potentially lowering costs.

Using odometry drift to match ILI joint boundaries for run comparisons

Repeat coincident inline pipeline inspections are used to calculate defect-to-defect corrosion growth rates (CGRs) for accurate reinspection intervals. First, a pair of inspections is aligned at the boundaries between pipe joints. Pattern matching is then used to match individual defects on paired joints. Joint-boundary matching is a correspondence problem that can be described in terms of “drift”, which is the difference in odometry values at corresponding joint boundaries. Here, drift is formalized and characterized. It is used to describe current joint-boundary matching methods — interpolation, zippering, and direct odometry comparison. We use the drift formulation to illustrate why existing methods produce false matches (1) in the presence of poorly documented reroutes, (2) when there are nonlinearities in the odometry from pig speed changes, and (3) from other inspection problems. We develop a new evidence-based intuition for drift as the systematic bias of position-estimating state machines on inspecting pigs. This is followed by deriving a position-specific drift differencing distance metric using the first-order differencing of the drift. We show this value to be trend stationary. The results section compares the four metrics’ abilities to identify common joint-boundary matching challenges. We found that direct matching and interpolation are unreliable. These methods generate difficult-to-detect mistakes because they rely on a nearest-neighbor matching criterion. Zippering and drift differencing work much better. Both rely on pups in the vicinity of pipeline reconfigurations. They both fail when there are no pups or when a reconfiguration is large. Because zippering uses naive pattern-matching, it is subject to aliasing mistakes when non-corresponding joints are in analogous positions. In contrast, drift differencing, which is position-specific, is immune to this type of error. Finally, we show that the assumptions behind the derivation are valid for an example dataset.

Fatigue performance and failure mechanism of ductile iron pipes with socket joints under traffic loads

Urban water supply pipelines experience repetitive traffic loads during their operational lifespan, potentially leading to fatigue failure. However, existing research focuses primarily on the static or dynamic mechanical responses of pipes, with limited studies on the fatigue performance of pipes. This study investigates the fatigue performance and failure mechanism of DN200 ductile iron (DI) pipes with socket joints under traffic loads and water pressure through bending fatigue tests. First, the mechanical responses of pipe joints under traffic loads derived from statistical data on highway traffic loads, soil pressure, and self-weight are calculated using ABAQUS to give the fatigue test load amplitude. Subsequently, tests are conducted on three DN200 DI pipes under a water pressure of 0.2 MPa: one for a monotonic test and two for fatigue tests under extra car and bus loads, respectively. The fatigue life of pipes under various traffic load combinations is analyzed using cumulative damage theory. Moreover, the relationship between fatigue load amplitude and number of cycles for DN200 DI pipes are obtained on the basis of the test data. Results show that the maximum rotation angle of joint is an important indicator of failure. Finally, a theoretical method for calculating the joint angle is proposed on the basis of geometric dimensions. A good agreement between the test and theoretical results is observed. Thus, the proposed method can obtain the fatigue performance of joints effectively.

Collapse resistance of KT-shaped square steel pipe joints reinforced by corrugated plates

Collapse resistance of KT-shaped square steel pipe joints reinforced by corrugated plates

AUTOMATED LEAK AND WATER QUALITY DETECTION SYSTEM FOR PIPED WATER SUPPLY

The volume of water loss because of leakage in the conveyance pipe has been alarming. Old and poorly constructed pipelines, inadequate corrosion protection, poorly maintained valves, and mechanical damage contribute to leakage. Water-carrying pipes were buried underground, so tracing leak points manually could be tasking, if not impossible. This work was to report on the effectiveness of a developed Automated Leak and Water Quality Detection (ALWQD) system. This device can detect leaks in the piped water system automatically and can also report any deterioration in the quality of water that flows through affected pipes. The ALWQD consisted of several drainpipe connections, pipe accessories, electronic components, and sensors to monitor water quality impairment. The control signal was the solenoid valves that interfaced with the ESP-32 microcontroller boards placed on the pipe manifold at intervals, along with water quality monitoring sensors of turbidity, Total Dissolved Solids (TDS), and pH. The fabrication and testing of the device followed standard procedures. Testing of ALWQD was done at 0, 5, and 10 minutes under load and no-load conditions, with average variation in reading recorded after three trials. The findings indicated that the efficiency of ALWQD was between 70% and 80%, which could be improved upon. The trend in the results of the monitored parameters was not different from that of similar previous work. Leaks caused pressure drops and disallowed the full flow of water found at pipe joints, which could be a pathway for the intrusion of contaminants into the water conveyance system.

Effect of welding axial stresses on the strength of a welded pipe joint with a defect

Effect of welding axial stresses on the strength of a welded pipe joint with a defect

Failure law of hydraulic pipe joints sealing performance under vibration loads

Aviation hydraulic pipe joints are inevitably affected by vibration loads during service. Fatigue relaxation occurs in the pipe joint structure by vibration, and fretting fatigue wear occurs in its sealing interface, leading to a decline in sealing performance. In order to investigate the sealing performance of hydraulic pipe joints affected by vibration load, this paper first analyzes the modal distribution of the sealing system pipeline under different hydraulic pressures and hydraulic fluid flow rates through vibration frequency sweeping experiments. Secondly, the vibration load is applied to the pipe joints for different numbers of cycles, which reveals the microscopic wear behavior of the sealing interfaces under different tightening torques. Finally, by carrying out the leakage measurement experiment under vibration load, the evolution law of the sealing performance of pipe joints under different hydraulic fluid pressures and tightening torques was obtained.

Stress and deformation response of pipe jacking in upper-soft and lower-hard strata: A case study in Changsha

Constructing underground structures using the pipe jacking technique presents challenges in upper-soft and lower-hard strata. The complicated strata conditions make pipes prone to deflection, leading to problems such as cracking, pipe joints failure and water leakage. To determine the stress and jacking force characteristics of pipe jacking during the entire construction period in upper-soft and lower-hard strata, this paper presents a case study of pipe jacking passing through upper-soft and lower-hard strata in Changsha, China. Pipes stresses at two wings, and the top crest in the longitudinal directions for six different pipe sections were monitored. Then, a jacking force model is proposed to describe the additional thrust after deflection in upper-soft and lower-hard strata. The results show that the jacking force induced by upper-soft and lower-hard strata exhibits a tortuous increase and causes pipe deflection. The stress and deflection patterns in different monitoring pipes are consistent. The maximum pipe stresses during the jacking were 9.26 MPa in the longitudinal direction and 394 % increasing after deflection. Axial stress in test pipes exhibit nonlinearly transfer, with the distribution of friction resistance forms a“W”shape between pipes. An excessive alignment deflection would generate incremental jacking force, which strengthens with larger deflection. By regarding the composite formation area as a fully contact model with the surrounding rock, and uniform formation as a contact with the bottom of the surrounding rock, and the formulas were corrected for deeply buried pipe under uniform formation. Combining the calculation results and field data, the predict model is validated. The calculation method that can effectively predict the jacking force after pipe alignment deflection in upper-soft and lower-hard strata. The results of this study can provide beneficial guidance for the design and construction of pipe jacking.

THREADED LUBRICANTS FOR DRILL PIPES BASED ON OIL PRODUCTION WASTE

The oil and gas industry occupies a leading position in the development of the country's fuel and energy complex, and the effectiveness of its activities largely depends on the technical and economic indicators of drilling. When performing well work and operating oil and gas wells, many material costs are associated with the operation of oil pipes, namely the reliability of threaded connections operating at high pressures and temperatures in aggressive environments. The need to develop deeper and deeper horizons, the use of forced drilling modes, the transition to later stages of operation of most oil and gas fields, the aging of existing funds and the increase in the volume of overhauls leads to an increase in tripping operations, and therefore the requirements for the reliability of the connection of oil-grade pipes are moving to a new level. Studies have shown that up to 87 % of all drill string accidents are related to poor thread condition. This unsatisfactory condition of the locking threaded joints forces us to look for ways to improve durability. Many foreign and domestic scientists have been studying and improving threaded joints in drill pipes. According to the authors, one of the most promising ways to increase the TEI of drilling is to develop and use more and more effective lubricants for locking joints of drilling tools. Studies have shown that conventional lubricants are not effective enough in modern realities, and sometimes lubricants are completely washed out of threaded joints. In addition, as the drilling depth increases, the friction force increases and the hydrodynamic load increases, and the increase in pressure in the threaded connection complicates the conditions due to the effect on the lubricant of chemically active and abrasive drilling muds and many other factors. The article discusses the obtained results of studies of lubricant bases for threaded connections of drill pipes used for the oil industry, the distinctive features of which are physical and chemical composition, including low molecular weight polyethylene, synthetic rubber, rubber softeners, powdered graphite, vegetable oils.The authors of the article selected the basis of lubricant from industrial rubber production waste, and also presented the advantages of the developed lubricants and materials. The practical significance of the obtained research results lies in the possibility of increasing the wear and sealing properties of threaded pipe joints used in drilling oil and gas wells.

Effect of graphene content on the tribological and corrosion behavior of high-speed-laser-clad high-entropy-alloy composite coatings

To repair oil drill pipe joints that have failed owing to dry wear and tribocorrosion, graphene-reinforced CoCrFeMo0.5NiTi0.5 high-entropy alloy composite coatings (HEACCs) were developed through high-speed laser cladding. The HEACC containing 1.5 wt% graphene exhibited dry wear and tribocorrosion rates that were 59.18 % and 32.20 % of those observed in the high-entropy alloy coating, respectively. The HEACC exhibited a corrosion current density of 2.475 × 10−7 A/cm2. The HEACC containing 1.5 wt% graphene underwent progressive damage during dry wear owing to the combined effects of abrasive wear, which created furrows; adhesive wear, which led to flaking; and oxidative wear, which formed oxide layers. During tribocorrosion, chloride ions exacerbated surface damage caused by hard abrasives and asperities, intensifying corrosive–abrasive wear interactions.

Numerical simulation study on rubber ring for pipe jacking joint of electric power tunnels

Abstract To study the sealing properties and stress characteristics of the rubber ring in pipe jacking tunnel joints, the critical state value when the waterproof failure occurs is calculated using the expression of joint detail dimensions. The pipe joint installation finite element model is executed by ABAQUS software to optimize the rubber ring structure. Meanwhile, the pipe joint deflection angle and the installation gap are adjusted. The results indicate that the contact pressure and joint installation force of rubber rings significantly decreased. Moreover, the contact pressure exceeds 0.3 MPa, demonstrating that the optimized joint is more reasonable and reliable. When the pipe section deflects, the maximum allowable deflection angle is 0.02 rad. Exceeding this limit will result in leakage damage due to insufficient contact pressure. The installation gap has a significant impact on the stress of the rubber ring. With an installation gap between 7 and 13 mm, joint failure can be effectively prevented.

Design and Development of a Pipeline Maintenance System for Pipe Surge and Water Hammer Equipment Based on Siemens S7-1200 PLC

Fluids play a crucial role in the lives of living beings, as they are substances that can flow. In a piping system, a common issue is water pressure fluctuation caused by sudden closures of water flow (Idul, 2021). Pipe surge and water hammer equipment are utilized to demonstrate the transient pressure effect resulting from abrupt changes in flow velocity within pipes (David, 1981). Water hammer can lead to pressure surges throughout the piping system, potentially causing failures that result in leaks in pipes, valves, pipe joints, and even pumps if the pressure exceeds the pipe's capacity (Prasetya, 2016). The likelihood of pipe ruptures or leaks at joints increases significantly. Additionally, equipment movement, slope, and precision of pipe installation can also contribute to leaks during water hammer events. This research aims to develop a pipe leakage monitoring system to address the impact of water hammer. The system will be installed in areas deemed susceptible to this phenomenon, along with a periodic maintenance indicator system to minimize the impact of pipe leaks. The research will also investigate the potential risks associated with varying fluid flow rates in the piping system. The monitoring, indicator, and sensor systems will be integrated into a PLC and HMI system for data processing.

Application of Pattern Search and Genetic Algorithms to Optimize HDPE Pipe Joint Profiles and Strength in the Butt Fusion Welding Process

The rapid spread of the use of high-density polyethylene (HDPE) pipes is due to the wide variety of methods for connecting them. This study keeps pace with the developments of butt fusion welding of HDPE pipes by exploring the relationship between the performance of the weld joints by studying ultimate tensile strength and exploring the joint welding profiles by studying the shape of the joint at the outer surface of the pipe (height and width of the joint cap) and the shape of the joint at the internal surface (height and width of the joint root). Welding pressure, heater temperature, stocking time, and cooling time were the parameters for the welding process. Regression was analyzed using ANOVA, and an ANN was used to analyze the experimental results and predict the outputs. Two optimization techniques (pattern search and genetic algorithm) were applied to obtain the ideal operating conditions and compare their performance. The results showed that pattern search and genetic algorithms can determine the optimal output results and corresponding welding parameters. In comparison between the two methods, pattern search has a limited relative advantage. The optimal values for the obtained outputs revolved around a tensile strength of 35 MPa (3.45 and 4.5 mm for the cap and root heights, and 8 and 6.98 mm for the cap and root widths, respectively). When comparing the effects of welding parameters on the results, welding pressure had the best effect on tensile strength, and plate surface temperature had the most significant effect on the welding profile geometries.

Field monitoring and numerical simulation for force characteristics of pipe jacking in deep buried moderately weathered slate

Understanding the force characteristics of pipe jacking in rock formations is crucial for ensuring the stability of the structure and construction safety during construction. Yet, very little is explored about its characteristics in rock formations of pipe jacking. This paper presents a case study of constructing a deeply buried moderately weathered slate sewage pipeline using pipe jacking method in Changsha, China. To this end, we propose a novel method to combine field monitoring and numerical simulation representation in an efficacious way. Field monitoring was conducted to investigate the spatial distribution characteristics of jacking force, axial stress, and hoop stress in moderately weathered slate. Numerical simulation methods were employed to discuss the influences of several factors on pipe stress: the pipe-rock contact area, contact relationships at pipe joint interfaces, the height of the jacking force position, and the depth of pipe burial. The results show that hand shield is influenced by the excavation technology, and the distribution of jacking force exhibits a stepped or oscillating upward pattern in moderately weathered slate. The maximum axial stress occurs at the mid-span position of the arched roof of pipe at 30 MPa. Hoop stresses are dominated by compressive stresses with the maximum at-8 MPa. As the pipe burial depth increases, so does the axial stress on the pipe. Lower positioning of the jacking force heightens this stress effect. A larger pipe-rock contact area correlates with reduced axial stress levels. The weakening of the contact interface between pipe joints minimally affects axial stress, as stress primarily transmits through non-weakened areas. To ensure the reliability of the data, automatic monitoring and measuring instruments calibrated for on-site monitoring are used. The results of this study can provide beneficial guidance for the design and construction of pipe jacking.