Pipe Thickness Research Articles

Study on short-term mechanical properties of multi-reinforced steel-plastic composite pipe under internal pressure

A multiple-reinforced steel-plastic composite pipe (MRSPCP) is a new type of composite pipe developed in China recent years. The MRSPCP is composed of high-density polyethylene (HDPE) matrix, steel-wire mesh, and steel strip. It is an improved version of the traditional structural wall pipe, and it is able to carry both external and internal pressures. Nowadays, it has been employed in many projects that require large diameter and high flow media transportation, such as water distribution systems, drainage systems, agricultural irrigation systems. As the MRSPCP is newly developed, its mechanical properties and failure mechanism are not clear, and its design method lacks theoretical basis, so this paper carries out the experimental, theoretical and simulated research to investigate the short-term mechanical properties of the MRSPCP. Firstly, uniaxial tensile tests are carried out to acquire the mechanical properties of the constituents. As the steel wire is curly and it is hard to get the stress-strain relationship directly, an inverse identification method was applied to determine the mechanical parameters of a bilinear model representing the steel-wire mechanical behavior. Moreover, short-term burst tests of the MRSPCP are carried out to assess its mechanical performance and provide data for the verification of the theoretical and simulated research. Secondly, a theoretical model is established to calculate the failure pressure by constructing force equilibrium relationship along the axial and hoop directions of the MRSPCP respectively, based on elastic mechanics. In the end, a finite element model of MRSPCP is established, considering the nonlinear mechanical property of the materials. Both the theoretical and the simulated results agrees well with the burst test result, with the relative error of only −13.18% and −4.41% respectively. As the finite element model not only provides more accurate result, but also it can demonstrate contour plots of different constituents inside the MRSPCP, the model is used to study the effects of the pipe thickness, composite strip winding angle and steel-wire diameter on the mechanical properties of MRSPCP. This study might be a guide for the design and safe application of the MRSPCP and similar composite pipes.

Industrial Experiment of the Online Accelerated Cooling for 27SiMn Seamless Steel Pipe

An online accelerated cooling equipment for seamless steel pipe is introduced, which can cool the inner and outer surfaces of seamless steel pipe simultaneously. Through industrial experiments, the 27SiMn test steel pipe is subjected to an online accelerated cooling process with a final cooling temperature of 510–590 °C. The outer diameter, wall thickness, and length of the test steel pipe are 180, 20, and 13000 mm, respectively. This process successfully upgrades its mechanical property grade from the original J55 to the N80 grade, with yield strength of 603–630 MPa, tensile strength of 830–839 MPa, elongation of 22–24%, and impact toughness of 35–37 J at 0 °C.

ESTIMATION OF ELECTRICITY CONSUMPTION FOR WATER TRANSPORTATION IN PRESSURE PIPELINES AFTER THEIR REPAIR

The issues of using pipes made of different materials in water supply systems and the current situation with the technical condition of pressure pipeline transport are considered. It is noted that in order to ensure the standard service life of pipelines, it is necessary to carry out high-quality repair and restoration work using trenchless technologies and modern building materials, which include polymer pipes and flexible hoses. The object of research is a section of a dilapidated steel pipeline network of a certain thickness, diameter, depth and groundwater level above the tray. For the renovation of the pipeline, internal protective coatings are used, applied by dragging new pre-compressed polymer pipes and flexible polymer sleeves based on fiberglass. A description of trenchless technologies is presented, as well as automated programs that implement the tasks of determining the technological parameters (wall thickness of a polymer pipe and a polymer sleeve), hydraulic calculation of pressure losses depending on the degree of roughness of the pipeline walls, the inner diameter of a new two-layer pipe structure when passing a certain water flow, as well as the amount of electricity consumed for water transportation when appropriate wall thicknesses of protective coatings.

Optimizing Pipeline Bridge Components Through FEA Technical Validation

Pipeline bridges are structures characterized by their triangular truss designs, which provide support and stability for pipelines. They have been used for centuries to span gaps and are still widely employed today in various forms and applications. This paper aims to explore the technical and economic aspects associated with optimizing the performance of a pipeline bridge by modifying the constitutive elements. It was investigated how variations in geometric elements and other design characteristics can influence the stress state and the associated material costs, so as to find solutions and strategies that allow the obtaining of a more efficient, safer, and more economical structure, without compromising quality or safety. Different construction scenarios were analyzed, revealing a stress increase of up to 54.77% in comparison to the lowest stress scenario (Scenario 6). Lower stress values were achieved using thicker pipes, with minimal influence from angle dimensions. A statistical analysis using ANOVA, performed in Minitab, showed that both maximum stress and material costs are predominantly influenced by pipe type (99.7% and 81.72%, respectively), rather than angle size. The optimal solution for minimizing stress and costs was determined to be the combination of angle C1 (30 × 30 × 3 mm) and pipe T3 (60.3 × 3.6 mm). This work contributes to the state of practices by providing detailed guidelines on selecting structural configurations that balance cost and performance, making it highly relevant for the design and optimization of pipeline bridges.

Corrosion Rate Prediction for Underground Gas Pipelines Using A Levenberg-Marquardt Artificial Neural Network (ANN)

Abstract This study addresses the challenge of accurately predicting corrosion rates and estimating the remaining life of underground gas pipelines, which is complicated by the complex interaction of physical factors and environmental conditions. Traditional models are inadequate in capturing these variables, leading to less reliable predictions, which this study aims to address by developing a more accurate and optimized artificial neural network (ANN) model. This study focuses on predicting corrosion rates and estimating the remaining life of underground gas pipelines using ANNs implemented in MATLAB. It incorporates both physical factors, such as maximum corrosion depth and pipe thickness, and environmental variables such as moisture, soil resistivity, and chloride concentration. The analysis identified corrosion depth and wall thickness as significant contributors, influencing material integrity by 20% and 16%, respectively. The optimal ANN model, with a Levenberg-Marquardt structure and one hidden layer of 10 neurons, achieved superior accuracy, with an MSE of 0.038 and R² of 0.9998. The study addresses the challenge of accurately predicting corrosion rates and remaining life in underground gas pipelines by developing an optimised ANN model. Its contribution lies in creating a highly accurate prediction tool that outperforms traditional models and enables more informed decisions for pipeline maintenance and safety.

Exploring microstructural evolution in a thick gauge high strength niobium-microalloyed line pipe steel

Exploring microstructural evolution in a thick gauge high strength niobium-microalloyed line pipe steel

Modal analysis of PE pipeline under seabed dynamic pressure

This paper presents a modal analysis conducted under seabed dynamic pressure conditions. The polyethylene (PE) pipeline was approximated as a thin-walled long cylindrical shell. The impact of pressure on the pipeline structure was considered, the study investigated the circumferential dynamic characteristics. The natural characteristics of the structure were solved using the energy method. To validate the model, an experimental testing system was established to measure the natural frequencies of the polyethylene (PE) pipeline, capturing the first three natural frequencies and mode shapes of the structure. Additionally, we conduct a simulation analysis in COMSOL. The results showed that the discrepancies among the experimental, theoretical, and simulation results were within 6%, confirming the accuracy of the model. Building on this foundation, the simulation considered the impact of fluid-structure interaction on the natural frequencies of the cylindrical shell. Subsequently, the effects of pipe radius, pipe thickness, pipe length, variations in external load, and dimensionless parameters on the modal characteristics of the structure were further investigated. The comparison of simulation and theoretical results showed errors within 5%, further validating the reliability of the simulation outcomes.

Experimental and numerical study on thermal performance of energy storage interior wall with phase change materials

Phase change materials (PCM) and embedded tube radiant terminals demonstrate considerable advantages with respect to heat storage, energy savings, and the provision of comfort in buildings. This paper puts forth the concept of an energy storage interior wall (ESIW) with embedded pipe radiant technology, comprising PCM, and coupled with low-grade energy sources. Compared to traditional TABS, this system uses PCM energy storage to compensate for the instability of solar energy supply, which expands the application scenarios of clean energy. At the same time, it can greatly improve the thermal mass of the building and provide cooling and heating for multiple rooms. Experimental results demonstrate that the ESIW is capable of markedly enhancing the thermal comfort and indoor temperature, with an average increase of 9.9 °C relative to the outdoor. In the numerical study based on test data, sensitivity analysis was performed on 10 characteristic parameters of the ESIW structure: wall thickness, wall density, wall thermal conductivity, wall specific heat capacity, PCM phase change temperature, PCM pipe diameter, PCM enthalpy, PCM pipe length, pipe flow diameter, and number of rows of PCM pipes. The results show that the key parameters affecting the first objective (thermal storage capacity) are: pipe flow diameter, wall density, wall thickness, and PCM pipe diameter; and the key parameter affecting the second objective (investment cost) is the diameter of the PCM pipe. After multi-objective optimization for these two objectives, the thermal storage capacity of the ESIW was improved by 96.7 %, and the investment cost was reduced by 11.49 %.

Experimental Performance Study on Axial Compressive Load-Bearing Capacity of Steel Slag Micropowder Ecotype UHPC of Short Columns Steel Pipe

In order to study the axial compression performance of steel pipe concrete short columns filled with steel slag micronized ultra-high-performance concrete (UHPC), this paper designs 27 steel pipe UHPC short columns for axial compression test and compares and analyzes the axial compression performance of the specimens in terms of the damage mode, the deformation curve, and the coefficient of strength enhancement, which is aimed at investigating the differences in the actual load-bearing performance of steel pipe UHPC short columns through changes in the aspect ratio, concrete type, and steel content rate, and so on. The purpose of this paper is to compare and analyze the axial compressive performance of the specimens in terms of damage mode and strength enhancement factor in order to investigate the difference in the actual bearing capacity performance of steel pipe UHPC short columns through the changes in length-to-diameter ratio, concrete type, and steel content. The test results show that the axial compressive performance of steel slag powder steel pipe UHPC short columns is greatly affected by the L/D ratio and steel content; the specimen bearing capacity increases with the increase in the wall thickness of the steel pipe and decreases slightly with the increase in the L/D ratio, and the steel fibers can effectively improve the deformation of the concrete so as to enhance the composite effect with the steel pipe; the contribution of the core UHPC to improve the value of bearing capacity accounts for a higher percentage when UHPC with 1% steel fiber dosage and 20% coarse aggregate dosage gave the best uplift with no change in the type of steel pipe. In this paper, the axial compression test bearing capacity results of steel slag micro powder steel pipe UHPC short column are compared with the calculated bearing capacity results of domestic and international specifications and analyzed from the perspectives of perimeter compression strength, steel fiber mixing of core concrete, and the relevant parameter design suggestions for high-strength steel pipe concrete specimens are put forward.

Curved-pipe flow with boundary conditions involving Bernoulli pressure

In this article, we study the steady-state flow of the incompressible viscous fluid through a thin distorted pipe with an arbitrary central curve. We prescribe the inflow and outflow boundary conditions involving the Bernoulli pressure with a given pressure drop. Using the multiscale expansion technique with respect to the pipe's thickness, we construct the higher-order asymptotic approximation of the flow given by the explicit formulae for the velocity and pressure. We also perform a detailed error analysis justifying the usage of the proposed solution and indicating its order of accuracy. For more information see https://ejde.math.txstate.edu/Volumes/2024/63/abstr.html

Modelling and experimental study on pipeline defect characterisations using a pulsed eddy current measurement

ABSTRACT Pipelines are widely used as the main transportation method in petrochemical and metallurgical industries. However, the special nature of the materials transported in pipelines means they are often subjected to high temperature, high pressure and corrosive conditions. This can lead to defects, such as thinning and cracking, resulting in pipeline failure and causing serious economic losses. Therefore, regular non-destructive testing of pipelines is particularly important. This paper uses the non-destructive testing method with pulsed eddy current technology to characterise pipeline thinning and defects. A preliminary study is conducted on the pulsed eddy current detection signal patterns for pipeline crack defects with varying orientations and quantities. A more portable pulsed eddy current detection device with an extended wall thickness detection range is developed. It can achieve measurements with a maximum thickness of 30 mm for detections of pipelines with rectangular defects and thickness-stepped reduced. The experimental results are consistent with modelling results, and the accuracy for pipelines with insulation layer is also investigated. On-site measurements using the PEC system are conducted on equipment sections with pipe thickness within 20 mm in a petrochemical plant. It is confirmed that the developed PEC inspection device can accurately characterises the thickness of pipelines with 0–50 mm cladding.

Experimental modal analysis of in-plane bending vibration mode using actual water main network

Accidents of water leakage and bursting due to deterioration of water pipes cause water outages and economic losses in the surrounding areas. We are conducting research to develop measurement and diagnostic methods for buried water pipes. The graphitic corrosion of water pipes in a buried environment causes a reduction in pipe thickness which leads to strength problems. For this reason, methods for detecting pipe thickness are necessary for evaluating pipe deterioration, however, there is no effective way to analyze pipe thickness today because it cannot be visually observed in a buried environment. In this study, we focused on the shift in eigenfrequencies of in-plane bending vibration of rings due to deterioration. At first, we performed an experimental modal analysis by using a water pipe network which is used in a practical water utility. In addition, we conducted a theoretical analysis based on a model of a two-dimensional ring with coupled incidental attachment. As a result, in-plane bending vibration was observed in the water pipe of actual size. Furthermore, in-plane bending vibration was observed when excited through fire hydrants and it is also observed in pipes that are different material and diameters.

A Review of the Properties of Different Concrete-Filled Steel Tube Columns

This paper mainly analyzes different types of concrete-filled steel tube columns to compare different parameters such as loading angle, eccentricity, different steel pipe thickness, different strength grades of concrete, different cross-sectional shapes, etc., and elaborates the changes of mechanical properties of the specimens under the influence of different parameters. The formulas of axial compression and flexural bearing capacity of different concrete-filled steel tube columns and the bearing capacity of concrete-filled steel filled steel tubes after fire were proposed, and the interaction of various materials in the components was studied in depth. The proposed studies are summarized.

A simplified analytical solution of pipeline response under normal faulting

Buried pipelines are one of the critical lifeline structures, and the evaluation of pipeline performance under seismic faulting is essential for protection of pipeline networks. This paper explores an analytical solution incorporating implementation of Winkler models around a beam-type structure using the finite difference method to evaluate the pipeline response under normal faulting. The effectiveness of the analytical solution is assessed by comparing the calculated pipe strains with centrifuge and full-scale laboratory testing measurements. Subsequently, the effect of pipe size, faulting condition, and burial condition on pipe response are investigated. It can be found that a pipeline with a smaller pipe wall thickness or larger pipe diameter is generally more prone to failure. Larger pipe wall thickness or lower D/t ratio should be used for pipe design crossing an active fault. In geotechnically problematic areas, shallow burial depth and less stiff soil with lower modulus are recommended to reduce the probability of exceedance of allowable limit states due to normal faulting. In the end, empirical functions relating to critical D/t ratio are proposed to evaluate the critical states of fault displacement, burial depth, and spread of fault rupture with different diameter-to-thickness ratio considering the controlled limit of failure modes.

Temperature Effect on Deformation Mechanisms and Mechanical Properties of Welded High-Mn Steels for Cryogenic Applications.

High-manganese steel (high-Mn) is valuable for its excellent mechanical properties in cryogenic environments, making it essential to understand its deformation behavior at extremely low temperatures. The deformation behavior of high-Mn steels at extremely low temperatures depends on the stacking fault energy (SFE) that can lead to the formation of deformation twins or transform to ε-martensite or α'-martensite as the temperature decreases. In this study, submerged arc welding (SAW) was applied to fabricate thick pipes for cryogenic industry applications, but it may cause problems such as an uneven distribution of manganese (Mn) and a large weldment. To address these issues, post-weld heat treatment (PWHT) is performed to achieve a homogeneous microstructure, enhance mechanical properties, and reduce residual stress. It was found that the difference in Mn content between the dendrite and interdendritic regions was reduced after PWHT, and the SFE was calculated. At cryogenic temperatures, the SFE decreased below 20 mJ/m2, indicating the martensitic transformation region. Furthermore, an examination of the deformation behavior of welded high-Mn steels was conducted. This study revealed that the tensile deformed, as-welded specimens exhibited ε and α'-martensite transformations at cryogenic temperatures. However, the heat-treated specimens did not undergo α'-martensite transformations. Moreover, regardless of whether the specimens were subjected to Charpy impact deformation before or after heat treatment, ε and α'-martensite transformations did not occur.

Comparative Analysis of Water Hammer Performance in Different Pipe Parameters with FSI

Water hammer (WH) is a critical phenomenon in fluid-filled piping systems that can lead to severe pressure surges and structural damage. The characteristics of the pipe material, geometry, and support conditions play a crucial role in the fluid–structure interaction (FSI) during WH events. This study investigates the impact of various pipe parameters, including material, length, thickness, and diameter, on the WH behavior using an FSI-based numerical approach. A comprehensive computational model was developed based on the algorithm presented in Delft Hydraulics Benchmark Problem (A) to simulate the WH phenomenon in pipes made of different materials, such as steel, copper, ductile iron, PPR (polypropylene random copolymer), and GRP (glass-reinforced plastic). This study examines the influence of pipe parameters on WH performance in pipelines, utilizing FSI to analyze the phenomenon. The results show that the pipe material has a significant influence on the pressure wave speed, stress wave propagation, and the overall system response during WH. Pipes with lower modulus of elasticity, such as PPR and GRP, exhibit lower pressure wave speeds but higher stress wave speeds compared with steel pipes. Increasing the elastic modulus, pipe wall thickness, length, and diameter enhances the pipe’s stiffness and impacts the timing, magnitude of pressure surges, and the likelihood of cavitation. The findings of this study provide valuable insights into the design and mitigation of WH in piping systems.

Effects of uneven wall thickness of steel pipes on magnetic permeability perturbation testing for internal defects

ABSTRACT Magnetic Permeability Perturbation testing (MPPT) has the advantage of high sensitivity for deeply buried defects in steel pipes. However, in complex working conditions, variations in the partial wall thickness of the pipe can affect the defect detection results. The paper discusses the influence mechanism of uneven wall thickness on the MPPT of internal defects on steel pipes and analyzes the magnetic field distribution caused by uneven wall thickness which influences on the magnetic permeability perturbation (MPP) of internal defects. The MPP is enhanced at the thinning wall and weakened at the thickening wall. The effect of uneven wall thickness on MPPT signals is confirmed through simulation and experiment. The signal of defects in thinning wall is enhanced, while the signal of defects in thickening wall is weakened. The greater the wall thickness variation, the degree of signal distortion is more significant. Experimental results show that uneven wall thickness has an effect on the detection of the defects with different depths. Finally, a method using deep saturation magnetisation is proposed to mitigate the inconsistent signals caused by uneven wall thickness. The findings will contribute to quantitative evaluation of defects in MPPT.

Vibration characteristics analysis and structural optimization of bio-organic fertilizer mixer based on finite element method

Abstract In order to solve the waste produced by grape planting and cattle and sheep breeding in the Turpan area, this paper puts forward an organic liquid fertilizer mixer, and analyzes the vibration characteristics of the main structure-mixing barrel and auger. The finite element model of the mixer structure is established by Ansys, and the modal analysis is carried out in combination with the actual application. The analysis structure shows that the minimum natural frequency of the mixer barrel is 51.993 Hz, the minimum natural frequency of the auger is 12.601 Hz, in which the natural frequency of the auger is less than its working frequency of 48.5 Hz, and there is resonance risk. To improve this problem, the structure of the mixing auger is optimized, the length of the auger is reduced, and the pipe thickness and diameter are increased. The improved modal analysis shows that the minimum natural frequency of the auger is 50.371 Hz, which avoids the working frequency and will not cause resonance.

Thermally Induced Nonlinear Bending and Stability of Nanocomposite Curved Pipes Reinforced by CNTs

This research is concerned with the thermal bending and stability of temperature-dependent nanocomposite curved pipes strengthened with carbon nanotubes (CNTs) subjected to uniform temperature rise. Thermo-mechanical characteristics of the polymer composite pipe are assumed to vary entirely in the thickness by a non-uniform function of the radius. Five different patterns are selected to model the propagation profile of CNTs amongst the pipe thickness. Based on the shear deformation and von-Karman kinematic hypothesis, nonlinear balance equations of the polymer curved pipe are determined via varying the total potential energy of the system. Governing equations as a set of coupled nonlinear differential equations are analytically solved using a perturbation-based technique. Closed-form solutions are derived to estimate large-amplitude deflection of nanocomposite curved pipes with pinned and clamped boundaries under uniform thermal loading. The obtained results show the influences of important parameters such as material/geometrical characteristics and foundation stiffness on the thermally induced nonlinear response of polymer nanocomposite curved pipes.

Experimental investigation on mechanical properties of fiber recycled concrete filled-square steel tube columns under pure flexural based on acoustic emission technique

Currently, global countries are actively focusing on carbon emission reduction. Utilizing recycled aggregate concrete (RAC) is expected to realize global carbon neutrality objectives. However, due to its inherent mechanical limitations, its application in structural contexts is restricted. This study aimed to enhance the mechanical attributes of RAC and expand its utility beyond low-strength applications. By employing recycled aggregates, steel fibers, and ordinary Portland cement, a novel eco-friendly composite filler was developed for steel- tube filling. A comprehensive study on 16 concrete mix ratios and 23 steel-tube recycled concrete columns was conducted. The parameters included the recycled aggregate volume, steel fiber content, and steel pipe thickness. The results revealed that reasonable mix design enabled RAC to exhibit flexural performance similar to that of conventional steel-tube concrete. Moreover, while increasing the recycled aggregate content deteriorated the overall mechanical properties, incorporating steel fibers extended the elastic stage and enhanced the flexural characteristics. Optimal results were achieved with 1.2 % steel fiber addition and 75 % recycled aggregate. The comparison between the derived equation and the experimental data demonstrated a high level of agreement, confirming the accuracy of the equation. Furthermore, acoustic emission technology was employed in this experiment to monitor the failure progression of steel tube recycled concrete columns subjected to a pure bending load. The findings revealed a triphasic failure process: elastic, elastic-plastic, and strengthening stages. The analysis demonstrated a consistent correlation between acoustic emission parameters and waveform characteristics with the failure process of the specimen. Empirical evidence demonstrated the efficacy of acoustic emission technology in effectively monitoring the damage severity and failure chronology in recycled concrete steel pipe columns during bending.