Search

The shear deformation of the steel strip layer is introduced for the first time into the constitutive model of steel strip reinforced thermoplastic pipes (SSRTP), aiming to obtain a more precise solution for the burst pressure. Five SSRTP specimens with end fittings were employed to conduct the burst pressure test. Accordingly, two sets of FE models which are friction-inclusive and friction-neglecting were established. The friction-inclusive FE model demonstrates good agreement with the test solution, while the friction-neglecting FE model aligns well with the theoretical solution. The findings indicate that for wide strip layers, the shear deformation is not negligible. The impacts of additional tensile armour, winding angle, and friction coefficient on the burst pressure were analyzed. Finally, a linear correction is applied to account for the influence of the friction coefficient, yielding a result that can be regarded as the lower limit of the SSRTP's burst pressure. [ABSTRACT FROM AUTHOR]

This research comprehensively addresses the influence of structural properties and polymer type on the mechanical performance of bilayer vascular grafts. The grafts consist of inner layers with randomly distributed polycaprolactone(PCL)/polylactic acid(PLA) or poly(l-lactide-co-caprolactone)(PLCL) fibers and an outer layer with radially oriented PLCL fibers, manufactured through a sequential electrospinning process. Highlighted results indicate that tubular scaffolds possess an inner layer ranging in thickness from 62 to 94 µm, while their outer layers vary in thickness from 180 to 296 µm. In addition, radially oriented fibers enhance tensile strength in radial direction (9–11 MPa), while depending on polymer composition and wall thickness proportions of individual layers, tensile strength values change between 2.7 and 7.7 MPa in longitudinal direction. Scaffolds with elastic PCL or PLCL inner layers display higher compliance values (above 1%/mmHg × 10−2). [ABSTRACT FROM AUTHOR]

Hydrogen, as a clean energy carrier, presents a significant step toward sustainable energy solutions but faces challenges in storage due to its low energy density and high volatility. This study addresses the optimization of Type V hydrogen storage tanks by investigating the burst pressure performance of spherical, cylindrical, and toroidal shapes. Using finite element analysis (FEA) and first-order shear deformation theory, we examined how these geometries impact burst pressure outcomes across a range of composite materials and layup configurations. The materials tested included carbon T700/epoxy, Kevlar/epoxy, E-glass fiber/epoxy, and basalt/epoxy. Results demonstrate that the toroidal shape significantly outperforms spherical and cylindrical designs in stress distribution and burst pressure, with basalt/epoxy composites exhibiting superior burst pressure performance (12.7 MPa) compared to Kevlar/epoxy (10.8 MPa), E-glass fiber/epoxy (11.4 MPa), and carbon T700/epoxy (8.9 MPa). Kevlar/epoxy toroidal tanks outperform other materials in weight performance, having a structural performance index of 0.0305 Mpa.m3/kg and hydrogen density per unit mass of 0.0251 kg H 2 /kg. The stacking sequence [-45/45]s optimized stress distribution for the toroidal shape across all materials. The findings highlight that toroidal designs offer significant advantages for high-pressure hydrogen storage, providing efficient stress management and improved safety. This paper underlines the potential of toroidal vessels for enhancing hydrogen storage efficiency and emphasizes the importance of material selection and stacking sequences in achieving optimal burst pressure performance for international organization for standardization (ISO) certification. • Toroidal tanks show superior burst pressure over spherical and cylindrical designs. • The [-45/45]s stacking sequence optimizes stress distribution for toroidal tanks. • Basalt/epoxy composites outperform other materials in burst pressure performance. • Kevlar/epoxy toroidal tank outperforms others in weight performance. • Toroidal tanks offer efficient stress management and enhanced safety for hydrogen storage. [ABSTRACT FROM AUTHOR]

This study investigated the effects of different braid materials (polyethylene terephthalate, nylon 6, and their hybrid), weaving frequencies of the braids (7, 9, 11, 13 Hz), and concentrations of polyether sulfone solution (15% and 18 wt%) on braid angles, braid thickness, and bursting resistance. The results showed that for all types of single and hybrid braids, the braid angle decreases with increasing spinning frequency. When spinning frequency was increased from 7 to 13 Hz, the average wall thickness of polyethylene terephthalate, nylon 6, and the hybrid braids increased by approximately 50%, 65%, and 60%, respectively. The bursting pressure results were obtained in the range of 9.3 to 20.2 bars. The Fourier transform infrared spectroscopy results revealed no chemical bond between the braids and the polyether sulfone layer. Optical and electron microscope analyses revealed formation of uniform thickness of the polyether sulfone layers on the surface of the braids, as well as the penetration of polyether sulfone into the gaps between the filaments. The analyses also showed macroscopic adhesion of polyether sulfone to the braids and provided information on the amount and size of the pores in the polymer layers. The results showed that the selection of appropriate weaving frequency, braid materials, and polyether sulfone layer concentration are important as controllable parameters for producing polymeric hollow fiber composites with excellent burst pressure resistance. [ABSTRACT FROM AUTHOR]

A process and Structural Health Monitoring system was implemented on a Composite Overwrapped Pressure Vessel (COPV) for hydrogen storage at 350 bar to be used in a fuel-cell system of an Unmanned Aerial Vehicle. This work reports the embedment strategy of optical fibre Bragg grating (FBG) sensors to monitor the full life cycle of the vessel, consisting of an aluminium liner and a wound carbon fibre reinforced polymer composite overwrap. A FBG sensing array, bonded on the aluminium liner circumferential section, was covered with a localised unidirectional prepreg composite tape, enabling composite winding and curing monitoring. The sensing array strategy allowed to detect and locate Barely Visible Impact Damage resulting from drop-weight impact tests, based on the ratio of the residual strain amplitude between FBG sensor pairs. Errors as small as 17 mm and up to 56 mm were determined between the predicted and 'real' impact locations. To simulate the real-life operational pressure charging and discharging cycles, the COPV was subjected to cycling testing at different pressure ranges. The FBG sensors were able to monitor a total of 20 980 pressure cycles, revealing a linear response to the applied pressure, and remained operational after COPV failure. Furthermore, the FBG sensing array was able to detect the residual plastic strain caused in the aluminium liner by the autofrettage process that the COPV was subjected to prior to pressure cycling, at 600 bar for 2 min, to improve its fatigue performance. This manuscript also reports the COPV structural design by Finite Element Modelling (FEM), its manufacturing process and burst pressure testing for the FEM analysis validation. A small difference of 0.7% was found between the simulated and experimental determined burst pressure of 1061 ± 26 bar. [ABSTRACT FROM AUTHOR]

This paper provides a synthesis of the results of experimental research and numerical simulations on polyethylene pipes subjected to short-time hydraulic pressure testing. Also, the current paper offers basic information about the engineering behavior of High-Density Polyethylene (HDPE) under the aforementioned test. HDPE presents high levels of technical performance because it has a high-density resin, high molecular weight, and bimodal Molecular Weight Distribution (MWD). HDPE pressure pipelines are used in Drinking Water Distribution Networks (DWDNs) and are component pieces of the thermoplastic piping system. The experimental test was mainly oriented toward the comparative determinations of the burst pressure of both the defect-free pipes and those with a lack of material defects made through mechanical operations. Also, the experimental test establishes the short-time hydraulic failure pressure as well as the determination of the resistance of the polyethylene pipes to hydraulic pressure in a short time period. The numerical simulations were carried out with the purpose of validating the results obtained analytically and experimentally. [ABSTRACT FROM AUTHOR]

This study used the roto-evaporation technique to engineer a 6 mm three-layer polyurethane vascular graft (TVG) that mimics the architecture of human coronary artery native vessels. Two segmented polyurethanes were synthesized using lysine (SPUUK) and ascorbic acid (SPUAA), and the resulting materials were used to create the intima and adventitia layers, respectively. In contrast, the media layer of the TVG was composed of a commercially available polyurethane, Pearlbond 703 EXP. For comparison purposes, single-layer vascular grafts (SVGs) from individual polyurethanes and a polyurethane blend (MVG) were made and tested similarly and evaluated according to the ISO 7198 standard. The TVG exhibited the highest circumferential tensile strength and longitudinal forces compared to single-layer vascular grafts of lower thicknesses made from the same polyurethanes. The TVG also showed higher suture and burst strength values than native vessels. The TVG withstood up to 2087 ± 139 mmHg and exhibited a compliance of 0.15 ± 0.1%/100 mmHg, while SPUUK SVGs showed a compliance of 5.21 ± 1.29%/100 mmHg, akin to coronary arteries but superior to the saphenous vein. An indirect cytocompatibility test using the MDA-MB-231 cell line showed 90 to 100% viability for all polyurethanes, surpassing the minimum 70% threshold needed for biomaterials deemed cytocompatibility. Despite the non-cytotoxic nature of the polyurethane extracts when grown directly on the surface, they displayed poor fibroblast adhesion, except for SPUUK. All vascular grafts showed hemolysis values under the permissible limit of 5% and longer coagulation times. [ABSTRACT FROM AUTHOR]

Transportation relies heavily on petroleum products, forcing the adoption of alternative energy sources like hydrogen. Hydrogen is considered the cleanest fuel for the twenty-first century due to its water-based combustion and no CO2 emissions. However, challenges persist in production, utilization, and storage; employing composite material-based high-pressure storage vessels is increasing in the hydrogen storage sector. The paper analyzes the impact of the winding angles on the mechanical performance of the filament wound Type 4 composite pressure vessels (CPVs) for compressed hydrogen gas storage at 70 MPa. This work examines the individual winding angles and combined angles winding patterns to promote the efficiency of Type 4 CPVs by achieving maximum burst pressure, ensuring safe burst mode, and reducing CPV weight by applying maximum principal stress theory with the aid of the Ansys ACP Prep/Post and static modules. The weight and burst pressure of CPVs are significantly influenced by fiber orientation; a combination of positive and negative helical winding angles promotes higher burst pressure at a lower weight. A hoop angle and intermediate helical angles can be combined to create high-efficiency CPVs that provide mechanical performance comparable to that of a combination of high and low helical angles. Finally, a one-factor-at-a-time (OAT) sensitivity analysis was performed to determine how the winding angle and the thicknesses of layers affect the CPVs' performance. It was found that the performance of the CPVs is significantly influenced by the thicknesses of the wound layers.

The lightweight high-pressure hydrogen storage vessels composed of polymer liner and composite reinforced layers have attracted more and more attention. In this research, a 2D axisymmetric finite element model was proposed to predict the damage evolution, failure strength and failure mode of the composite overwrapped pressure vessels, in which a user subroutine UMAT based on Hashin failure criteria was introduced to simulate the progressive damage properties of the composite material. The FE models are validated by comparison with the experimental results, and the error between the numerical simulation results and the experimental results was within 10%. It is found that vessels with different lay-up schemes might burst in different locations. Parametric studies are performed to obtain a critical ratio of hoop and helical layers to keep the vessel burst in safe mode. [ABSTRACT FROM AUTHOR]

Introduction: The staple line (SL) leak remains one of the most serious complications after laparoscopic sleeve gastrectomy (LSG). The present study aims to determine whether reinforcing the SL with sutures is effective in maintaining tissue integrity. Materials and Methods: LSG Specimens of 60 patients were ex vivo studied. The specimens were divided into three groups: In group 1, the entire SL was reinforced, while the upper half part of the SL was reinforced from fundus to antrum in group 2. The SL was not reinforced in group 3. Then, the pressure inside the sample was increased, and the bursting pressure location and pressure value during the bursting were recorded. Results: The bursting pressure was significantly higher in entire and half oversewed SL groups than the none reinforced group (group 1: 115 mmHg [95–170]; group 2: 95 mmHg [80–120]; group 3: 40 mmHg [22–60], respectively, [P < .001]). The most common site of bursting was in the middle ⅓ of SL (35, 53.8%), followed by the proximal ⅓ part of SL (18, 27.7%), and the distal ⅓ part of SL (12, 18.5%), respectively. The bursting site was significantly more frequent in the corpus than the other parts of the SL (P = .013). Conclusion: Reinforcing the SL with sutures preserves tissue integrity. Although bursting was most frequently observed in the corpus region ex vivo, the fact that almost all real-life leaks develop in the area close to the Angle of His. This situation suggests that strengthening the suture line with reinforcement alone will not be protective enough against leaks in the fundus line, and factors such as tissue ischemia may be considered. [ABSTRACT FROM AUTHOR]

An effective numerical analysis process was carried out to simulate an impact event based on the Hashin failure criterion and the Camanho degradation rule. The middle and shoulder of a cylinder were impacted by the edge of square-shaped impactors, and the remaining burst pressure was predicted. The accuracy of the numerical analysis was verified by results of two experiments that proved that the numerical analysis was reliable. The impact damage at different impact energies (20-200 J) was evaluated. According to the analysis carried out, the impact damage of gas cylinders intensified with increasing impact energy, and there existed a critical value of this energy. The damaged area of gas cylinders under the same impact energy first decreases and then increases from the inner to outer layer, and the maximum increase in the residual bursting pressure could reach 9.6%. [ABSTRACT FROM AUTHOR]

This study utilized finite element modeling to assess the stress and burst strength of a composite pressure vessel (CPV). The fiber type and its sequences were considered while developing the best CPV. The stress produced inside the CPV may cause damage to the vessel as well as loss of life and property. Therefore, it is critical to guarantee that the CPV's stress output does not surpass the vessel material's maximum allowable stress value. The primary goal of this research is to investigate the stresses induced in composite pressure vessels and then examine the stress using three different solutions: von Mises, Tresca, and ASSY. The theoretical burst strength is first established, and then a numerical solution is developed using ABAQUS. To confirm the correctness of FEA, the outcomes of the theoretical technique and the finite element method are compared. The six-layer carbon fiber-reinforced CPV shows twelve times higher burst strength than four layers but an equal thickness of jute fiber-based CPV. On the other hand, the hybrid combination of CPV (jute and carbon) shows a strength improvement over jute fiber based CPV by almost four times. Other jute fiber-based hybrid CPVs with glass, banana, and aluminum foil show very comparable strength relative to only jute CPV. This study's primary goal is to examine the failure phenomena and burst strength of thin, cylindrical pressure vessels.

Shanshan Wang, Ying Hua, Jun Liu, Zhifan F Huang, Jeffrey W Clymer, Crystal D Ricketts, Jin Hao Ethicon, Inc, Cincinnati, OH, USACorrespondence: Jeffrey W Clymer, Ethicon, Inc, 4545 Creek Road, Cincinnati, OH, 45242, USA, Email jclymer@its.jnj.comBackground: Design of surgical staplers continues to advance with more consistent staple formation that can lead to higher leak pressures and lower rates of leak along the staple line. This study was performed to compare the Ethicon Echelon™+ Stapler with Thunderbird reloads to two other currently available commercial staplers, Reach Anzhi and Fulbright Lunar with corresponding reloads.Methods: The rate of malformed staples for three staplers was determined in porcine stomach (3.0– 3.3 mm thickness) via CT scanning. Staple line air leak pressures in bronchial tissue (3.0– 3.3 mm) and fluid leak pressures in colon (1.3– 1.7 mm) were measured and compared to a standard success criterion for both tissues.Results: The rate of malformed staples in gastric tissue for Echelon+ was more than 90% lower than for the two other commercial staplers (p < 0.001). In bronchus, Echelon+ had 56% higher air leak pressures than Reach Anzhi (p < 0.001) and was not significantly different from Fulbright Lunar. In colon, Echelon+ had over twice the fluid leak pressures of the comparators (p < 0.001).Conclusion: The Echelon+ Stapler with Thunderbird reloads exhibited a low rate of malformed staples, and its staple lines withstood high leak pressures in both thick and thin tissues. Clinical studies are needed to confirm that these observed benefits carry over into actual practice.Keywords: stapler, endoscopic, burst pressure, malformed staples, leaking

Purpose: The high-pressure accumulator has been widely used in the hydraulic system. Failure pressure prediction is crucial for the safe design and integrity assessment of the accumulators. The purpose of this study is to accurately predict the burst pressure and location for the accumulator shells due to internal pressure. Design/methodology/approach: This study concentrates the non-linear finite element simulation procedure, which allows determination of the burst pressure and crack location using extensive plastic straining criterion. Meanwhile, the full-scale hydraulic burst test and the analytical solution are conducted for comparative analysis. Findings: A good agreement between predicted and measured the burst pressure that was obtained, and the predicted failure point coincided very well with the fracture location of the actual shell very well. Meanwhile, the burst pressure of the shells increases with wall thickness, independent of the length. It can be said that the non-linear finite element method can be employed to predict the failure behavior of a cylindrical shell with sufficient accuracy. Originality/value: This paper can provide a designer with additional insight into how the pressurized hollow cylinder might fail, and the failure pressure has been predicted accurately with a minimum error below 1%, comparing the numerical results with experimental data. [ABSTRACT FROM AUTHOR]

Most transmission pipelines are buried underground per regulations, and external corrosion is the leading cause of failures of buried pipelines. For assessing aged pipeline integrity, many corrosion assessment models have been developed over the past decades. This paper delivers a technical review of corrosion assessment models for determining the remaining strength of thin- and thick-walled pipelines containing corrosion defects. A review of burst prediction models for defect-free pipes is given first, including the strength- and flow-theory-based solutions, and then of those for corroded pipes. In terms of the reference stress, the corrosion models are categorized into four generations. The first three generations correspond to the flow stress, ultimate tensile stress (UTS), and a combined function of UTS and strain-hardening rate, while the fourth generation considers the wall-thickness effect. This review focuses on recent advances in corrosion assessment methods, including analytical models and machine learning models for thick-walled pipelines. Experimental data are used to evaluate these burst pressure prediction models for defect-free and corroded pipes for a wide range of pipeline steels from low to high grades (i.e., Grade B to X120). On this basis, the best corrosion models are recommended, and major technical challenges and gaps for further study are discussed.

Burst pressure is an essential parameter to measure the residual bearing capacity of pipelines with corrosion defects. Accurate prediction of burst pressure is beneficial to evaluate the remaining life of pipelines. The traditional estimation formulas mainly focus on single-point corrosion but seldom consider the case of multipoint corrosion. Although DNV-RP-F101 considers multipoint corrosion, this method only considers the influence of axial spacing of adjacent corrosion defects on burst pressure but does not consider the influence of circumferential spacing. This work refers to the pipe corrosion criterion (PCORRC) and DNV-RP-F101 methods and modifies the calculation formula of the PCORRC method by introducing (D−t). The average relative error is only 11.46%, which is 27.65% lower than the previous formula. In addition, this paper presents a method for estimating the burst pressure of pipelines with multipoint corrosion defects. This method considers not only the axial spacing between defects but also the circumferential spacing. The results show that the maximum relative error is 6.52%. A machine learning modeling framework for predicting burst pressure in multipoint corroded pipelines is proposed. The case using radial basis function neural network as the prediction tool shows that the average Pearson correlation coefficient of the prediction results in the test set is 0.903, indicating that the prediction performance is good. [ABSTRACT FROM AUTHOR]

Copyright of China Rural Water & Hydropower is the property of China Rural Water & Hydropower Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To study the stability of the over-pressure reinforcement effect of the copper tube at room temperature, the burst tests for the small diameter soft TP2 copper tube at room temperature during the natural aging time of 0, 6, 12 and 24 months were carried out respectively. These results indicated that: the mean of the measured burst pressure did not change significantly for small diameter soft TP2 copper bare tube and rifled tube at the same pretreatment pressure during the natural aging time of 0, 6, 12 and 24 months, respectively. The standard deviation was gradually smaller and the over-pressure strengthening effect was obvious. The measured burst pressure was different obviously for small diameter soft TP2 copper tube at the pretreatment pressure was 4.60 MPa and 16.50 MPa respectively during the same natural aging time, the mean was significantly larger and standard deviation was significantly smaller for measured burst pressure with the increase of pretreatment pressure, the results showed that pretreatment pressure had a great influence on strengthening effect, and higher pretreatment pressure could get better strengthening effect. The burst pressure conforms to the normal distribution for the same small diameter soft TP2 copper tube at the same over-pressure reinforcement during the natural aging time shall not exceed 24 months. Over-pressure reinforcement at room temperature was a suitable method to increase burst pressure of soft TP2 copper tube, and the method could be used in engineering.

A composite pressure vessel is an important structure in different applications including pipes, pipes under pressure and closed system pipes under high pressure and temperature such as gas pipelines and aircraft structures, because of the characteristics of polymer – a composite used as an alternative to heavy materials such as metal in the various applications, including the construction industry. The current work focuses on the study of strength phase orientation and their properties on the burst pressure strength and other parameters, which are very important in the design and manufacture of these vessels such as the selection of type of strength phase nylon 6, 6 and philosophy of mixing of the type of fiber with matrix material (epoxy). The work also includes the study of the effect of two layer angle ply (0, 90), (55, –55), (75, –75) and implements different material testing to evaluate the toughness and stiffness of these vessels and compare the experimental result with the theoretical result. A filament winding apparatus was designed and executed to manufacture different types of subjects according to these angle of ply nylon fiber. The mechanical tests (tensile test, drop test, pipe stiffness test, hydrostatic pressure test) were used to test the vessel. The results shown that the ply orientation (75, –75) has high (tensile strength, toughness, stiffness, impact and burst pressure) when compared with the results from other ply orientations. This shows that [75, –75] ply orientation is the optimal angle for the vessel. Tensile tests show that (75, –75) ply orientation samples have higher properties in two directions, longitudinal and transverse, when compared with other angles.

In this study, a new rupture disk corrosion test (RDCT) method was developed for real-time detection of stress corrosion cracking (SCC) initiation of Alloy 600 in a primary water environment of pressurized water reactors. In the RDCT method, one side of a disk specimen was exposed to a simulated primary water at high temperature and pressure while the other side was maintained at ambient pressure, inducing a dome-shaped deformation and tensile stress on the specimen. When SCC occurs in the primary water environment, it leads to the specimen rupture or water leakage through the specimen, which can be detected in real-time using a pressure gauge. The tensile stress applied to the disk specimen was calculated using a finite element analysis. The tensile stress was calculated to increase as the specimen thickness decreased. The SCC initiation time of the specimen was evaluated by the RDCT method, from which result it was found that the crack initiation time decreased with the decrease of specimen thickness owing to the increase of applied stress. After the SCC initiation test, many cracks were observed on the specimen surface in an intergranular fracture mode, which is a typical characteristic of SCC in the primary water environment.

Most transmission pipelines are buried underground per regulations, and external corrosion is the leading cause of failures of buried pipelines. For assessing aged pipeline integrity, many corrosion assessment models have been developed over the past decades. This paper delivers a technical review of corrosion assessment models for determining the remaining strength of thin- and thick-walled pipelines containing corrosion defects. A review of burst prediction models for defect-free pipes is given first, including the strength- and flow-theory-based solutions, and then of those for corroded pipes. In terms of the reference stress, the corrosion models are categorized into four generations. The first three generations correspond to the flow stress, ultimate tensile stress (UTS), and a combined function of UTS and strain-hardening rate, while the fourth generation considers the wall-thickness effect. This review focuses on recent advances in corrosion assessment methods, including analytical models and machine learning models for thick-walled pipelines. Experimental data are used to evaluate these burst pressure prediction models for defect-free and corroded pipes for a wide range of pipeline steels from low to high grades (i.e., Grade B to X120). On this basis, the best corrosion models are recommended, and major technical challenges and gaps for further study are discussed. [ABSTRACT FROM AUTHOR]

In this study, neat PCL, neat PLA and PLA/PCL (50/50) based tubular surfaces are produced by electrospinning to simulate the native blood vessel structure and to investigate the effects of both graft material and fiber orientation on burst strength. The burst pressure values of these vascular graft structures that designed with both randomly oriented fibers and oriented fibers, measured by a customburst pressure tester, and the results are compared. The results show that fiber orientation have a great influence on burst pressure, regardless of the type of biomaterial. It is determined that grafts with oriented fibers have at least twice the burst strength than those with random fibers. The findings indicate that changing the graft material has also an effect on burst strength. When the results are analyzed by polymer type, although the PLA100_O sample has the highest burst strength among all oriented fiber sample groups, it is better to determine the vascular graft candidate by taking into account radial elasticity. [ABSTRACT FROM AUTHOR]

Thick-walled cylindrical vessels are specially used in oil, chemical, nuclear and military industries in order to withstand internal pressure. The presence of the compressive residual stress in the walls increases the bursting pressure and fatigue life. Autofrettage processes and radial interference in multilayer cylinders are among the conventional methods of creating residual stresses in the pressure vessels. In order to achieve higher strength and fatigue life, the combination of these processes is also considered. J integral method is a suitable criterion for evaluating the crack parameters in elastic and elastoplastic strain fields. In this research, distribution of the J integral along the semi-elliptical crack front on the inner surface of the interferenced two-layered cylinder with closed end has been studied. Inner layer was autofrettaged. Burst pressure was determined based on the fracture toughness criterion (JΙC). Also, the effects of the autofrettage percent, radial interference; depth, angle and aspect ratio of the crack on the J integral and burst pressure variations have been investigated. The inner and outer layers of the cylinder were made of 7075-T6 aluminum alloy. The periodic nonlinear hardening behavior of this alloy has been predicted using Chabooche model. The validity of the results and their accuracy were examined. [ABSTRACT FROM AUTHOR]

Background: Tissue welding is an electrosurgical technique that can fuse tissue for small intestine anastomosis. However, limited knowledge exists on its application in mucosa-mucosa end-to-end anastomosis. This study investigates the effects of initial compression pressure, out-put power, and duration time on anastomosis strength ex vivo in mucosa-mucosa end-to-end anastomosis.Methods:Ex vivo porcine bowel segments were used to create 140 mucosa-mucosa end-to-end fusions. Different experimental parameters were employed for fusion, including initial com-pression pressure (50kPa–400 kPa), output power (90W, 110W, and 140W), and fusion time (5, 10, 15, 20 s). The fusion quality was measured by burst pressure and optical microscopes.Results: The best fusion quality was achieved with an initial compressive pressure between 200 and 250 kPa, an output power of 140W, and a fusion time of 15 s. However, an increase in output power and duration time resulted in a wider range of thermal damage. There was no significant difference between the burst pressure at 15 and 20 s (p > 0.05). However, a substantial increase in thermal damage was observed with longer fusion times of 15 and 20 s (p < 0.05).Conclusion: The best fusion quality for mucosa-mucosa end-to-end anastomosis ex vivo is achieved when the initial compressive pressure is between 200 and 250 kPa, the output power is approximately 140W, and the fusion time is approximately 15 s. These findings can serve as a valuable theoretical foundation and technical guidance for conducting animal experiments in vivo and subsequent tissue regeneration.

In this study, the burst pressure of thin-walled pressure vessels made of carbon steel is numerically simulated and verified by experimental results. The effect of the length-to-diameter ratio on the burst pressure is analyzed. The numerical and experimental results are compared. [ABSTRACT FROM AUTHOR]

Background: Staple line reinforcement (SLR) is commonly used in bariatric surgeries to reduce leaks and bleeds. With the evolution of staplers, the need for buttressing with the latest surgical stapling technology is in question. The efficacy of GORE® SEAMGUARD® (G-SLR) to improve staple line strength based on an established measure of burst pressure was evaluated. A benchtop test on synthetic tissue evaluated the pressure required for staple line leak across surgical staplers with and without G-SLR. Methods: Staple lines on a consistent thickness synthetic bowel were pressurized to the point of failure (burst pressure) among Ethicon®, Intuitive®, and Medtronic® surgical staplers with and without G-SLR. Burst pressure and leak location (through the staple line [TTSL] or through the staple [TTS], on the anvil or cartridge side) were recorded. Visual confirmation of a leak concluded each test. Results: The pooled mean burst pressure for G-SLR was greater (p < 0.05) by 0.494 pounds/square inch compared with no reinforcement with no meaningful differences among staplers. Leak failures were primarily TTS (91.7%) and equally distributed between reinforcement groups with more leak failures on the cartridge side with G-SLR and on the anvil side for non-SLR group. Leaks occurred across the length of staple lines with no discernable pattern. Conclusion: Employing a buttressing material strengthens the staple line, as measured by burst pressure, and may reduce the risk for staple line failure. This benchtop study of G-SLR with three commonly used surgical staplers demonstrated a significant increase in burst pressures among the studied stapling devices. [ABSTRACT FROM AUTHOR]

Radiofrequency (RF)-induced tissue fusion shows great potential in sealing intestinal tissue without foreign materials. To improve the performance of RF-induced tissue fusion, a novel self-cooling jaw has been designed to minimize thermal damage during the fusion. The prototype of self-cooling jaws was developed and manufactured. A total number of 60 mucosa-to-mucosa fusions were conducted using ex-vivo porcine intestinal segments with the proposed design and conventional bipolar jaws. The effects of intestinal fusion were evaluated based on temperature curves, burst pressure, thermal damage, and histological appearances. The self-cooling jaws showed significant decrease in temperature during the fusion process. An optimal burst pressure (5.7 ± 0.5 kPa) and thermal damage range (0.9 ± 0.1 mm) were observed when the applied RF power was 100 W. The thermal damage range of the prototype has almost decreased 36% in comparison with the conventional bipolar jaws (1.4 ± 0.1 mm). The histological observation revealed that a decrease of thermal damage was achieved through the application of self-cooling jaws. The self-cooling jaws were proved to be effective for reducing the thermal damage during RF-induced tissue fusion, which could potentially promote the clinical application of tissue fusion techniques in the future. [ABSTRACT FROM AUTHOR]

This paper focused on the establishment of performance level and cost of plantain fibers reinforced High Density Polyethylene (HDPE) matrixes as gas pipeline material using pressure containment of the new materials as performance criterion. The cost of modified plantain fibers, the cost of plantain fibers reinforced HDPE (PFRHDPE) and the cost of PFRHDPE master batch (HDPE resin + plantain fiber particles + stabilizer, plasticizer) for pipes extrusion production and pipelines fittings injection productions were established. The burst pressure evaluated for available standard outside diameter ratio (SDR) using the ultimate tensile strength of PFRHDE is very much greater than the standard SDR design pressures even when the temperature derating factors were applied. The Maximum Allowable Operating Pressure (MAOP) of PFRHDPE and induced stresses of pressurized pipes established indicated that the new material is suitable for pipeline design for natural gas and liquid petroleum (LPG) lines. The PFRHDPE developed has better specific properties than the conventional steel and HDPE pipe material in terms of yield strength, elastic modulus and density of the new material. But in terms of cost, steel and HDPE has approximate desirability for selection with PFRHDPE. The energy required to manufacture and process steel products is about 480 MJ/m2, while that of plastics is about 320 MJ/m2. The study further established that PFRHDPE can be applied in the design of oil and gas gathering, transportation and distribution lines. [ABSTRACT FROM AUTHOR]

In order to meet the high requirements of future high-speed and high acceleration tactical missiles for shell bearing capacity and heat protection function, the integrated structure-heat protection ϕ480 mm composite shell was prepared by dry winding process, in which the structure layer adopted T700 carbon fiber/cyanate ester composite, and the heat protection layer adopted composite heat protection structure. The internal pressure, acoustic emission and hydraulic burst tests had been done for integrated structure-heat protection ϕ480 mm shell. The strain variation law, the damage type and damage location of ϕ480 mm composite shell were researched. The structural integrity of external heat protection materials was evaluated. The capacity of bearing internal pressure load was also assessed for the integrated structure-heat protection ϕ480 mm composite shell. The results show that the strain of ϕ480 mm composite shell is linear with the pressure and increased with the raising pressure. The acoustic emission signals, such as resin cracking, monofilament fracture, fiber bundle fracture and delamination are distributed in the dome areas under the internal pressure. The Felicity ratio of ϕ480 mm composite shell is 0.96 after secondary loading. The bursting pressure of ϕ480 mm composite shell is 18.6 MPa, and the vessel characteristic coefficient reaches 42.1 km. The fiber fracture occurs in the dome areas. A small amount of fiber fuzzing, broken wire and whitening appear on the surface of the heat resistant layer material, and no delamination and shedding occur, maintaining good structural integrity.

The shift from metallic to composite pressure vessels for storing compressed natural gas (CNG) is driven by the goal of reducing environmental impact by using lighter higher-performing structures. This work focuses on enhancing the internal pressure strength of a type IV composite overwrapped pressure vessel (COPV) by optimising the stacking sequence of the overwrapping composite layers. Parametric finite element (FE) models are developed to reveal symmetry effects. In these models, both the thickness build-up and fibre angle variation at the turnaround zones are accurately modelled. Subsequently, the stacking sequence is optimised with the objective function of maximising burst strength. The parametric modelling demonstrates that representing the COPV as an axisymmetric continuum reduces computational costs in 5400× while yielding results comparable to full 3D continuum models. Experimental burst tests are carried out to validate the numerical predictions, and the difference in pressure between them is 12.6 %. • Development of lightweight composite pressure vessels for energy storage. • Realistic representation of fibre orientation and thickness build-up on the domes. • Four different symmetrical models to understand symmetry effects. • Computational models validated against manufacturing and testing. [ABSTRACT FROM AUTHOR]

• Investigated failure pressure of composite pipelines with different corrosion sizes. • Elucidated damage process of corroded pipelines rehabilitated by the Kevlar liners. • Evaluated the rehabilitative effect of Kevlar liners on offshore pipelines. Offshore pipelines transport oil and natural gas that contain different corrosive contaminants, leading to internal corrosions. The presence of internal metal loss problems can significantly degrade the load-bearing capacity and reliability of pipelines over time. To address this issue, a Kevlar liner, offering a more accessible and cost-effective solution, is employed for repairing corroded pipelines. However, a quantitative assessment of the rehabilitating effect of Kevlar liner has been lacking. This study performed an investigation of the burst pressure of internal corroded pipelines reinforced with the Kevlar liner through a combination of experimental testing and finite element numerical simulations. While previous research primarily concentrated on single external defect, this study has investigated the burst pressure of pipelines in the presence of both single and dual internal corrosion defects. The results indicated that the presence of two corrosion defects further decreases the burst pressure of the pipelines. This study examined the reinforcement mechanism of Kevlar liner, revealing that it largely postpones the stress development in the corrosion zone and thereby enhances the ultimate internal pressure load-bearing capacity of the pipelines. Moreover, the contact stress resulting from the friction between the Kevlar liner and the steel pipeline contributes to the overall improvement in the load-bearing capacity of the corroded offshore pipelines. [ABSTRACT FROM AUTHOR]

Background: Numerous techniques have been described for fashioning gastrojejunostomy (GJ) in a Roux-en-Y gastric bypass. These include hand-sewn anastomosis (HSA) and mechanical anastomosis; the latter includes circular stapled anastomosis (CSA) or manual linear stapled anastomosis (mLSA). More recently, this list also includes powered linear stapled anastomosis (pLSA). The aim of this study was to analyse if addition of power to stapling would improve the integrity of GJ anastomosis in ex vivo porcine models. Subjects and Methods: The present study included five groups – mLSA1, mLSA2, HSA, CSA, and pLSA. Sequential infusions of methylene blue-coloured saline were performed into the GJ models. Pressure readings were recorded till the point of leak denoting burst pressure (BP). Total volume (TV) and site of leak were recorded. Compliance was calculated from the equation ΔTV/ΔBP. Results: Differences in pouch and intestinal thickness were not statistically significant between the models. BPs were higher in the mechanical anastomosis groups, i.e., pLSA 21 ± 9.85 mmHg, CSA 20.33 ± 5.78 mmHg, mLSA1 18 ± 4.69 mmHg and mLSA2 11 ± 2.94 mmHg, when compared to HSA 9.67 ± 3.79 mm Hg, which was found to be statistically significant (Kruskal–Wallis test, P = 0.03). Overall, the highest BP was recorded for powered stapling followed by circular, and then, linear stapling; however, this difference was not statistically significant (P = 0.86). There was no statistically significant difference among groups with regard to compliance (Kruskal–Wallis test, P = 0.082). Conclusion: Despite the limited number of samples, mechanical anastomosis showed a statistically higher BP when compared to HSA, suggesting better anastomotic integrity. The pLSA group showed promising results with the highest BP recorded among all groups; however, this did not reach statistical significance.

This study aims to investigate the effect of the polymer pair meltdown process and mechanical properties using three different laser transparencies 20%, 30% and modulated, ranging from a minimum 27% to a maximum 47%. The cross-sections of joints were analysed with an optical microscope. Burst pressure was performed to evaluate the strength of welded joints produced with different laser welding process parameters. Welding parameters, scanning speed and meltdown were varied and their influence on the quality of the polymer joint was recorded and evaluated. With the increase of meltdown, a more molten volume of polymer can be seen in the cross-section area. It was shown that with the increase of meltdown, the formation of pores occurred due to the high energy concentration obtained within each laser scan passing across the weld seam. The decrease of burst pressure in all polymer pairs was observed with 0.33 mm and 0.34 mm targeted meltdown. Burn marks and burned lines were observed in joints with 20% laser transparency. Modulated laser transparency influenced non-homogeneous temperature distribution inside the joint, which influenced the formation of heat-affected zones (HAZ) and pores. A study of the influence of cooling time on joint formation showed that it is possible to variate total meltdown while changing cooling time until the joint is solidified. • Within the increase of meltdown, bigger weld flash occurred inside weld seam. • Peak weld strength observed at specific meltdown values. • The decrease of weld strength is influenced by defect formation inside seam. • Non-homogeneous melting, HAZ observed with modulated laser transparency polymers. • Total meltdown can be controlled by modulating cooling time. [ABSTRACT FROM AUTHOR]

Using ultrasound technology as one of the therapeutic methods, in which ultrasound waves of different frequencies and intensities are employed, has significantly contributed to enhancing and facilitating the treatment process of various diseases. A Hemostatic Ultrasonic Scalpel can entail considerable advantages by simultaneously performing two operations tissue cutting and coagulation of biological tissues. In the present study, employing experimental design through response surface methodology, the effect of ultrasonic power and the duration of vibration application on the tissue has been investigated. Two parameters, namely the burst pressure of the sealed vessel and the length of the thermal seal zone, were measured by pressure testing and analysis image of the thermal effect region at the sealed vessel area, respectively. The pressure test results demonstrated that an input power of 52 W and the application of vibrations for 8 s under a constant force of 10 N, showed the optimized maximum burst pressure equal to 1100 mmHg. Examination of the sealed vessel images revealed a linear increase in thermal damage with increasing input power., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

In this article, the parametric model for the stiffness characteristic and burst pressure of cord-reinforced air spring with winding formation is developed. Based on the non-geostrophic winding model and the assumption of cord cross-stability, the cord winding trajectory model of the capsule is established. Then, the anisotropic and nonlinear mechanics model of the capsule with complex cord winding trajectory variation characteristics is constructed by the classical thin-shell theory. The capsule state vector is solved by the extended homogeneous capacity precision integration method. Due to the complex coupling relationship between the capsule state vector and the internal air pressure, the stiffness characteristic is solved by the iterative integration method. The burst pressure of the air spring is solved by the Tsai–Hill strength theory. Eventually, the accuracy and reliability of the proposed method are verified by the experimental results. The effects of the material properties, winding parameters, and geometric structure parameters on stiffness characteristics and burst pressure are discussed. The results of this article provide an important theoretical basis for the performance design of cord-reinforced air springs with winding formation.

Composite Overwrapped Pressure Vessels (COPVs) are widely used in fields including aeronautics and by companies such as SpaceX to hold high pressure fluids. They are favored for these applications because they are far lighter than all-metal vessels, although they demand special design, manufacturing, and testing requirements. In this study, finite element modeling was used to conducted stress and damage assessments on a composite overwrapped pressure vessel that has a 4 mm thick aluminum core cylinder. To develop the optimum COPV, the lamina sequences, thickness, and fiber winding angle were considered. The relationship between these variables and the composite-overwrapped structure's maximum burst pressure bearing capacity was assessed. The ABAQUS composite modeler was used to design and generate 14 models of COPVs from carbon fiber/epoxy plies with a consistent thickness of 6.5 mm and various fiber angle orientations. The effects of the ply stacking order were analyzed by the finite element analysis approach for all designed models, which had 13 layers of uniform thickness but a varying fiber orientation. A ply stacking sequence of [55°, −55°] PP winding pattern had an optimum COPV design profile, with a burst pressure bearing capacity of 24 MPa. The stress–strain distribution along the geometry of the COPV was also obtained using the finite element method, and it was found that the distribution is uniform over the surface of the COPV and that its peak values are found towards the polar boss section of the COPV. Extreme stress gradients were noticed when the boss nears its geometrical transition to the dome phase. This factor is evident from the change in the ply thickness caused by the overlapped fiber orientation. The results obtained from this study are useful for the design and application of composite overwrapped pressure vessels. [ABSTRACT FROM AUTHOR]

The application of composites is increasingly extensive due to their advanced properties while the analysis still remains complex on different scales. In this article, carbon fiber reinforced polymer (CFRP) is modeled via asymptotic homogenization employing a representative volume element (RVE) with periodic boundary conditions. A multiscale mechanical model of CFRP is established to bridge the microscopic model, mesoscopic model, and macroscopic model. According to asymptotic homogenization, the coefficients of the material constitutive equation are calculated with volume-averaged stress and strain. Using the homogenized materials properties of CFRP, the tensile experiments of composite layers with the layout of [ (0 ∘ / 60 ∘ / 0 ∘ / − 60 ∘) 4 ] are carried out to validate asymptotic homogenization method. The results indicated that the asymptotic homogenization approach can be used to calculate the homogenized elastic moduli and Poisson's ratio of the whole structure, where the numerical results are basically consistent with test data. The sequent homogenized CFRP laminate model is applied to the mechanical analysis of type III composite pressure vessels, whereby burst pressure is accurately predicted. This work might shed some light on multiscale analysis of composite pressure vessels. [ABSTRACT FROM AUTHOR]

Off-label use of radiofrequency vessel sealing devices for intestinal thermofusion has been reported as an alternate approach for closing the small and large intestines. The study aimed to evaluate if reinforcing the thermofusion line with a modified N-butyl-2-CyanoAcrylate and methacryloxysulpholane produced improved burst pressure values in ex vivo swine jejunal loops. A suture-less full-thickness jejunal biopsy was performed with different radiofrequency vessel-sealing devices (Ligasure 5 mm: RFVS-1; Atlast 10 mm: RFVS-2; Cayman Maryland: RFVS-3), and reinforcement with modified cyanoacrylate Glubran-2 (G2) at the thermofusion defect was applied. Burst pressure(BP) values were compared with a control group, wherein a cold blade was utilized to obtain the biopsy, followed by the closing of the jejunum with seven Gambee sutures. Seventy (n = 70) jejunal loop samples were distributed into the experimental groups.The RFVS-1 and -2 groups exhibited BP values similar to those of the suture group. The RFVS-3 group showed significantly lower BP values (P < 0.05) than the suture group. Conversely, in the groups wherein G2 was applied, all BP values were comparable to those of the suture group. BP test in the RFVS-3G2 group showed significantly (P < 0.05) higher values in the group using the same instrument without the glue (RFVS-3). G2 has been shown to improve the BP on the defects created by instruments that are not completely efficient in intestinal thermofusion and sealing. This experimental model showed that the performance of full-thickness biopsies with RFVS devices and reinforcement with G2 provide feasible and promising results. • RFVS instruments can be employed to obtain intestinal biopsies and seal the intestinal loop. • Not all RFVS employed in this study achieved the same ability to perform closure of the defect in the intestinal loop. • RFVS-3 instruments resulted in significantly lower BP values when compared with the hand sewing technique, which is considered the gold standard technique. • When a thin layer of G2 was sprayed on the sealed defect, all groups showed similar results in comparison with the suture group. [ABSTRACT FROM AUTHOR]

• Use of rupture discs as safety protection for water heat pipe blackbody radiation sources. • Analyzed theoretical models for rupture discs in water heat pipes and performed burst pressure fitting calculations. • Experiments were conducted on the high temperature and pressure of water heat pipe with rupture discs. • The experiment confirms the theoretical analysis, with a maximum deviation of 4.50% at room and 3.74% at high temperature. Integrating heat pipe technology into blackbody radiation sources significantly enhances thermal consistency and accuracy. Nonetheless, at elevated temperatures, pressure fluctuations in water heat pipe blackbody systems may induce catastrophic failures. This issue was addressed by theoretically conceptualizing, engineering, and implementing rupture discs designed to alleviate pressure under predetermined conditions, thereby enhancing system safety. A water heat pipe blackbody source equipped with rupture discs was constructed, and a series of relevant empirical tests were executed. The burst pressure measured under standardized hydraulic evaluation reached 5.65 MPa, closely matching the theoretically calculated burst pressure of 5.60 MPa, with a minimal deviation of 0.88 %, thus confirming the model's precision. Under extreme testing conditions at 260 °C and 4.80 MPa, the rupture disc burst prematurely at 3.66 MPa due to rapid heating. However, in step heating scenarios, the rupture disc's performance was within 4 % deviation from the theoretical predictions, demonstrating its reliability. [ABSTRACT FROM AUTHOR]

• A universal new yield criterion is established based on the Tresca yield criterion and the Mises yield criterion. • Various burst pressure prediction models are evaluated using a full-scale burst pressure test database. • The burst pressure model based on the new yield criterion offers the optimal approach for predicting burst pressure. Pipelines are a crucial transportation infrastructure for the long-distance transport of natural gas, oil, and other hydrocarbons, typically conducted through thin-walled pipes (D / t ≥ 20). Accurate prediction of the burst pressure of thin-walled pipelines is essential for their safe and reliable operation. To enhance the prediction accuracy of the burst pressure for defect-free, straight, thin-walled pipes, a new numerical integration yield criterion was proposed between the Tresca and Mises criteria, using the mean value of Simpson's numerical integration (MSI) as the equivalent shear stress. A new burst pressure prediction formula was then constructed using the MSI yield criterion. The burst pressure predictions based on different yield criteria were compared with experimental data. Additionally, the burst pressure curves of the new prediction formula were plotted, and the relative errors between the new prediction formula and four existing prediction formulas were analyzed and compared. The results indicate that the new burst pressure prediction formula using the MSI yield criterion closely matches the experimental data, with the best relative error result within a confidence interval of ±1.3 %. The Lord parameter curve and plane stress curve of the MSI yield criterion exhibit good consistency with the experimental data of various ductile metal materials. The new burst pressure formula established by incorporating the MSI criterion provides a safe, economical, and reliable theoretical foundation for the design, manufacture, inspection, and safety assessment of thin-walled pipelines in production practice. [ABSTRACT FROM AUTHOR]

Abstract Buried oil and gas pipelines may face the threat of geological disasters such as landslides, faults, and floods. However, long‐term buried oil and gas pipelines often have corrosion defects, which bring greater challenges to the safe operation of pipelines. In this study, via the finite element analysis method validated by the testing results, the blasting pressure of a middle‐high strength pipeline with corrosion defects under an axial compressive load, the distribution of the von Mises stress on the pipeline surface, and the local buckling behavior of the pipeline were studied. In the analysis of the influencing factors, the axially compressive load, the size of the corrosion defects, and the characteristics of the pipeline material were studied. Based on 437 sample points, an artificial neural network was adopted to predict the burst pressure of a pipeline with corrosion defects. By comparing the prediction results with the numerical simulation results, the accuracy verification of the prediction model was conducted. When the axially compressive load increases to a certain value, the burst pressure of a pipeline with corrosion defects will begin to decrease rapidly as the axial compressive load increases. The larger the size of the corrosion defect, the smaller the burst pressure of the pipeline. The depth and length of the corrosion defect have a significant influence on the blasting pressure. The lower the steel grade of the pipeline, the smaller the Y/T ratio, and the lower the bursting pressure of the pipeline. Both the axial compressive load and the size of the corrosion defect affect the failure mode of the pipeline. When the corrosion defect's size is small and the axial compressive load is small, the pipeline material fails. When the corrosion defect's size is large enough, and the axial compressive load is large enough, the pipeline is prone to structural instability. An increase in the axial compressive load and the decrease in the corrosion defect's size cause the local stress concentration of the corrosion defects to become more significant. When the axial compressive load on the pipeline is small, the increase in the axial compressive load does not affect the bursting pressure of the pipeline, but it greatly increases the degree of the local buckling of the pipeline. A decrease in the depth and width of the corrosion defects and an increase in their length results in the local buckling of the pipeline becoming more severe.

Burst pressure of pipelines with longitudinal cracks located at the centre of rectangular dents varies with defect size and recent reports indicate that it could be very high for shallow cracks inside shallow dents and for cracks inside restrained dents. However, it is not clear whether cracks located in the flank of dents would have the same impact on burst pressure of pipelines with dent-crack defects. In addition, studies show that the location of maximum strain in circular dents shifts away from the centre towards the flank when dented pipes are pressurised, but the implication on the propagation of longitudinal cracks located in various parts of a dent has not yet been widely investigated. In this paper, models of pipelines with longitudinal cracks inside rectangular dents were created using the Finite Element Methods software Abaqus to analyse crack propagation and predict the associated burst pressure. The in-built Extended Finite Element procedure in Abaqus was used to model crack propagation through the pipe. The models were calibrated and validated using previously published results of burst tests and tests of material properties. The effect of longitudinal cracks in both the flank and centre of the dents on the burst pressure was analysed by varying the crack length, the crack depth, the dent depth, the internal pressure during dent formation and the dent constraint condition. The results show that longitudinal cracks in the flank of rectangular dents are more severe for pipeline integrity than cracks located in the centre of dents. Crack depth and crack location inside the dents are the most influential parameters when assessing dent-crack defects in pipelines. Their effects on burst pressure are magnified by crack length, dent depth and denting pressure.

The determination of the pressure-bearing performance of hydrogen storage tanks (HST) is integral to enhancing their operational safety and risk management capabilities. In this study, an inaugural development of low-cost critical failure pressure (BP c) prediction model for small samples was proposed, which was based on a combination of the fuzzy grey relational analysis (FGRA) and GM(1,N). Specifically, a total of 15 of BP c -related factors were proposed for analysis and projections based on the data from bonfire tests. Results from the FGRA indicated burst pressure was most closely linked to the initial filling pressure (R ij1 = 0.939) of tanks under fire scenario. The normal working pressure (R ij2 = 0.924) and the elasticity modulus (R ij3 = 0.871) also demonstrating significant impacts. Furthermore, three GM(1,N) prediction models which could estimate BP c with multi-factor coupling were developed. Increasing the number of input feature factors could enhance the predictive capability of GM model. The GM(1,16) had optimal prediction performance among the models, achieving a prediction accuracy of 99.8 %. As well, the mean absolute error (MAE) was 0.799 MPa while the mean absolute percentage error (MAPE) was 1.56 %. This paper offered a novel option for establishing the HST critical failure criterion safely and efficiently. • Obtained factors on design features, physicochemical, and external thermal load. • Clarified the main controlling factors which affected critical failure pressure. • Developed GM(1,N)-based models to predict critical failure pressure. • Suggestions on the safety of hydrogen storage tanks in service were proposed. [ABSTRACT FROM AUTHOR]

Steel pipelines are increasingly essential for many applications, including the transport of oil, natural gas, and soon hydrogen gas. Steel pipelines are subject to harsh operating conditions. Corrosion is considered to be the most common type of failure in steel pipelines. This report focuses on corrosion and assessment in gas and oil pipelines. The most common method of repairing corroded pipelines by composite repair is included in the review. Based on conservative codes and deterministic and reliable FEM approaches, different tool designs and models of corroded pipelines without and with repair are summarized and compared. The evaluation of defects in determining the failure pressure of pipelines and the study of the contribution of composite wrap repair to corroded pipelines are discussed. • Review paper. • Failure pressure prediction of corroded pipelines. • Repairing corroded pipelines. • Composite wrap contribution based on synthetic and natural fibers. • Conservative codes, deterministic and reliability FEM design of corroded pipelines approaches. [ABSTRACT FROM AUTHOR]

Subsea production system occupies an important position in the development of deep-sea resources. As a key part of the subsea production system, the safety and reliability of the pipeline system of the subsea production system is crucially important. In recent years, with the development of artificial intelligence technology, the use of machine learning algorithms for large-scale complex pipeline system to provide a possibility of safety assessment. This paper collects the burst pressure of the pipeline in the experiments and uses various machine learning methods to evaluate and predict. The XGBoost model with the best performance after preliminary selection, and the accuracy of this method is improved through hyperparameter optimization with Bayesian principle. The improved XGBoost model are explained based on the Forward Feature Selection method and SHAP analysis, compared with commonly pipeline industry standards. The results show that the improved XGBoost model can significantly improve the prediction of the burst pressure and can effectively assess the structural integrity and reliability of pipelines. Moreover, the influencing factors of the burst pressure of the pipeline are analysed, and it is concluded that t (thickness of the pipeline), L (length of corrosion) are the two most important factors influencing the pipeline burst pressure. • Different machine learning methods are compared and it is found that the XGboost model has the best predictive performance. • The improved XGboost model is explained based on the Forward Feature Selection method and SHAP analysis. • The improved XGboost model is compared with existing industry standards. [ABSTRACT FROM AUTHOR]