Rupture Pressure Research Articles

Permeability Variations Associated With Fault Reactivation in a Claystone Formation Investigated by Field Experiments and Numerical Simulations

AbstractWe studied the relation between rupture and changes in permeability within a fault zone intersecting the Opalinus Clay formation at 300 m depth in the Mont Terri Underground Research Laboratory (Switzerland). A series of water injection experiments were performed in a borehole straddle interval set within the damage zone of the main fault. A three‐component displacement sensor allowed an estimation of the displacement of a minor fault plane reactivated during a succession of step rate pressure tests. The experiment reveals that the fault hydromechanical (HM) behavior is different from one test to the other with varying pressure levels needed to trigger rupture and different slip behavior under similar pressure conditions. Numerical simulations were performed to better understand the reason for such different behavior and to investigate the relation between rupture nucleation, permeability change, pressure diffusion, and rupture propagation. Our main findings are as follows: (i) a rate frictional law and a rate‐and‐state permeability law can reproduce the first test, but it appears that the rate constitutive parameters must be pressure dependent to reproduce the complex HM behavior observed during the successive injection tests; (ii) almost similar ruptures can create or destroy the fluid diffusion pathways; (iii) a too high or too low diffusivity created by the main rupture prevents secondary rupture events from occurring whereas “intermediate” diffusivity favors the nucleation of a secondary rupture associated with the fluid diffusion. However, because rupture may in certain cases destroy permeability, this succession of ruptures may not necessarily create a continuous hydraulic pathway.

Continuum damage modeling through theoretical and experimental pressure limit formulas

In this paper, we developed a mathematical modeling to represent the damage of thermoplastic pipes. On the one hand, we adapted the theories of the rupture pressure to fit the High Density Polyethylene (HDPE) case. Indeed, the theories for calculating the rupture pressure are multiple, designed originally for steels and alloys. For polymer materials, we have found that these theories can be adapted using a coefficient related to the nature of the studied material. The HDPE is characterized by two important values of pressure, deduced from the ductile form of the internal pressure’s evolution until burst. For this reason, we have designed an alpha coefficient taking into account these two pressures and giving a good approximation of the evolution of the experimental burst pressures through the theoretically corrected ones, using Faupel’s pressure formula. Then, we can deduce the evolution of the theoretical damage using the calculated pressures. On the other hand, two other mathematical models were undertaken. The first one has given rise to an adaptive model referring to an expression of the pressure as a function of the life fraction, the characteristic pressures and the critical life fraction. The second model represents a continuum damage model incorporating the pressure equations as a function of the life fraction and based on the burst pressure’s static damage model. These models represent important tools for industrials to assess the failure of thermoplastic pipes and proceed quick checks.

Evaluation of tensile strength of tissue adhesives made of fibrin and cyanoacrylate used as reinforcement of colon suture in “ex vivo” swine

AimTo evaluate rupture pressures of tissue adhesives of cyanoacrylate (Omnex®) and fibrin (Evicel®), used as reinforcement in colonic suture from “ex vivo” swine. MethodsSurgical procedures were performed in the Surgical Technique Laboratory. From a division in segments of 10cm of descending colon and sigmoid colon from three “ex vivo” female swine, Landrace breed, which were resected in less than six hours after the slaughter time, 30 segments were selected, 10 of each animal. They were stored in saline solution 0.9% at 36°C, being randomly allocated in three groups (Control, Evicel and Omnex), each one containing 10 segments. ResultsThe lower and higher pressure values found in the groups Control, Evicel and Omnex were 36mmHg and 41mmHg, 70mmHg and 90mmHg, 90mmHg and 120mmHg, respectively. Containing statistical significance (p-value <0.0001) concerning the 2 to 2 comparisons (Control, Evicel and Omnex) with 95% trusting rate based on the application of the Turkey Method. ConclusionOne concludes that the use of tissue adhesives in anastomoses colonic in an experimental animal model of “ex vivo” swine increased the anastomoses rupture pressures. Among the tested adhesives, cyanoacrylate presented higher rupture pressure in relation to fibrin adhesive.

High-pressure modulation of the structure of the bacterial photochemical reaction center at physiological and cryogenic temperatures

The optical absorption and fluorescence response to external high pressure of the reaction center membrane chromoprotein complex from the wild-type non-sulfur photosynthetic bacterium Rhodobacter sphaeroides was investigated using the native pigment cofactors as local molecular probes of the reaction center structure at physiological (ambient) and cryogenic (79 K) temperatures. In detergent-purified complexes at ambient temperature, abrupt blue shift and accompanied broadening of the special pair band was observed at about 265 MPa. These reversible in pressure features were assigned to a pressure-induced rupture of a lone hydrogen bond that binds the photo-chemically active L-branch primary electron donor bacteriochlorophyll cofactor to the surrounding protein scaffold. In native membrane-protected complexes the hydrogen bond rupture appeared significantly restricted and occurred close to about 500 MPa. The free energy change associated with the rupture of the special pair hydrogen bond in isolate complexes was estimated to be equal to about 12 kJ mol−1. In frozen samples at cryogenic temperatures the hydrogen bond remained apparently intact up to the maximum utilized pressure of 600 MPa. In this case, however, heterogeneous spectral response of the cofactors from the L-and M-branches was observed due to anisotropic build-up of the protein structure. While in solid phase, the special pair fluorescence as a function of pressure exactly followed the respective absorption spectrum at a constant Stokes shift, at ambient temperature, the two paths began to deviate strongly from one other at the hydrogen bond rupture pressure. This effect was tentatively interpreted by different emission properties of hydrogen-bound and hydrogen-unbound special pair exciton states.

Design of integrated safety vent in prismatic lithium-ion battery

Safety vent is crucial to protect its users from unpredictable explosions caused by the increasing internal pressure of lithium-ion batteries. In order to prevent the explosion of the battery, a safety vent rupture is required when the internal pressure reaches a critical value. In conventional manufacturing, the cap plate and safety vent are fabricated separately and are then welded. In the current study, a manufacturing process, which includes backward extrusion and coining process, is suggested to produce an integrated safety vent, which also has the benefit of increasing the production efficiency. In order to design a backward extrusion process, an upper-bound analysis, which assumed a condition for the end of stroke, is used for the prediction of the forming load. Furthermore, the shape parameters of the coining process were determined as the stress of the notch part with the analytical model, which considers the stress concentration factor. The rupture test was performed to measure the rupture pressure of the safety vent. The results satisfied the required pressure of 8.5±0.5 kgf/cm2. Finally, the results predicted from the analytical models were compared with those of the experiment. It was shown that the predicted rupture pressure was in good agreement with the experimentally measured ones, with a maximum error rate of 3.8 %.

A machine learning approach to investigate the relationship between shape features and numerically predicted risk of ascending aortic aneurysm.

Geometric features of the aorta are linked to patient risk of rupture in the clinical decision to electively repair an ascending aortic aneurysm (AsAA). Previous approaches have focused on relationship between intuitive geometric features (e.g., diameter and curvature) and wall stress. This work investigates the feasibility of a machine learning approach to establish the linkages between shape features and FEA-predicted AsAA rupture risk, and it may serve as a faster surrogate for FEA associated with long simulation time and numerical convergence issues. This method consists of four main steps: (1) constructing a statistical shape model (SSM) from clinical 3D CT images of AsAA patients; (2) generating a dataset of representative aneurysm shapes and obtaining FEA-predicted risk scores defined as systolic pressure divided by rupture pressure (rupture is determined by a threshold criterion); (3) establishing relationship between shape features and risk by using classifiers and regressors; and (4) evaluating such relationship in cross-validation. The results show that SSM parameters can be used as strong shape features to make predictions of risk scores consistent with FEA, which lead to an average risk classification accuracy of 95.58% by using support vector machine and an average regression error of 0.0332 by using support vector regression, while intuitive geometric features have relatively weak performance. Compared to FEA, this machine learning approach is magnitudes faster. In our future studies, material properties and inhomogeneous thickness will be incorporated into the models and learning algorithms, which may lead to a practical system for clinical applications.

Ductile Rupture Pressure Prediction for Capped-Open Casing and Tubing Under Combined Loads

Casing and tubing is widely used as protective conduits during all the phases of operations and productions for the oil and gas industry. Recently, casing and tubing burst failure accidents often take place in high pressure and high temperature (HPHT) oil and gas wells during production. Therefore, it is very important to accurately predict casing and tubing bust strength in the casing and tubing design and operation process. PD CEN ISO-TR 10400 presents the ductile rupture model for capped-end conditions, but capped-end casing and tubing applied in oil fields is few. For this case, this document establishes the ductile rupture model for capped-open conditions under combined loads on the base of PD CEN ISO-TR 10400. Numerical and experimental comparisons show that the ductile rupture model for capped-open conditions under combined loads prediction values essentially coincides with burst data provided by PD CEN ISO-TR 10400.

Age dependence of critical pressure in the segments and branches of the circle of Willis

Spontaneous intracranial haemorrhage is one of the most dramatic neurological disasters. The source of haemorrhage is linked to the pathology of the arterial wall or is unknown. Because the risk of haemorrhagic stroke increases with age, we tried to investigate the relationship between age and rupture pressure of cerebral arteries. In the presented study, 51 segments of large cerebral arteries (at the level of the circle of Willis and its incoming and outgoing branches) were obtained from 33 cadaver brains aged 12–86 years. The segments were pressurized up to the rupture. The rupture pressure was noted. The highest observed pressure was 4.3atm in specimen aged 24 years. The lowest pressure 1.19atm was observed in specimen aged 80 years. The mean value of rupture pressure of all investigated segments was 2.28atm.Statistical analysis showed a nonlinear exponential decrease of the rupture pressure of the large cerebral arteries with age. The main conclusion from our study is that drop of cerebral arteries strength is observed to the age of 40. Later this lowering is visible but not so evident.

Experimental determination of rupture pressure and stress of adventitia of human middle cerebral arteries.

Background Intracranial arterial dissections might be attributed to the particular biomechanical properties of their specific layers. Also, knowledge of adventitia properties would be crucial in the context of intracranial balloon angioplasty. Aims The purpose of this work was to determine the rupture pressure of separated adventitia and compare it to intact cerebral arterial segments. Methods Brain specimens were harvested from 14 autopsy subjects (age range from 23 to 86 years). Pressure-inflation tests were conducted on proximal segments of middle cerebral arteries and separated adventitia layers from contralateral arteries to assess the rupture pressure values. Results The averaged rupture pressure of adventitia layers was 1.41 SD 0.25 atm (1072 SD 190 mmHg), whereas for intact arterial segments it was 2.32 SD 0.70 atm (1763 SD 532 mmHg) and diminished with age according to nonlinear regression trends. The difference beetween the aformentioned rupture pressures was positively correlated with rupture pressure of intact arterial segments ( R2 = 0.88; p < 0.001). Conclusions The obtained experimental results indicate a leading role of adventitia in building arterial strength under supraphysiological pressure conditions. The greater the rupture pressure of complete cerebral arteries, the smaller the contribution of adventitia in overall wall resistance.

Steam generator tube rupture simulation using extended finite element method

A steam generator (SG) is an important component of any pressurized water reactor. Steam generator tubes represent a primary pressure boundary whose integrity is vital to the safe operation of the reactor. SG tubes may rupture due to propagation of a crack created by mechanisms such as stress corrosion cracking, fatigue, etc. It is thus important to estimate the rupture pressures of cracked tubes for structural integrity evaluation of SGs. The objective of the present paper is to demonstrate the use of extended finite element method capability of commercially available ABAQUS software, to model SG tubes with preexisting flaws and to estimate their rupture pressures. For the purpose, elastic–plastic finite element models were developed for different SG tubes made from Alloy 600 material. The simulation results were compared with experimental results available from the steam generator tube integrity program (SGTIP) sponsored by the United States Nuclear Regulatory Commission (NRC) and conducted at Argonne National Laboratory (ANL). A reasonable correlation was found between extended finite element model results and experimental results.

Influence of gas on the rupture strength of liquid: Simulation by the molecular dynamics methods

The cavitation rupture strength of liquid is studied by the molecular dynamics methods for simple materials by the example of argon in the presence of neon. Results on negative rupture pressure are obtained for different concentrations of the gas dissolved in the system. A linear dependence between these parameters is established.

Tentative probes into some aspects of the pipeline rupture behind the 2014 Kaohsiung underground gas explosions

By collecting information from the indictment and news media reports, this paper tries to probe into some aspects of the course of the rupture failure in the pipeline that is believed to have led to the 2014 Kaohsiung gas explosion incident. Through approximate finite element analysis and engineering assessment of a similar pipe segment, insight can be gained on the sequence of longitudinal and circumferential fracture, as well as the relationship between the degree of wall thinning and rupture pressure. Some of the deductions are found to corroborate the visual appearance of the rupture. Other deductions need further information from a detailed mapping of the wall thickness of the ruptured segment to substantiate. A mass transfer analysis for the leakage rate is recommended to help identify the approximate time of rupture. A detailed charting of the positions of corrosion damage and possible asphalt coating damage on the three pipe segments inside the culvert may provide further clues for identifying the root cause of the rupture.

Sleep apnea after posterior cerebral artery aneurysm rupture and elevated intracranial pressure: a Chiari-like syndrome

• Sub-arachnoid hemorrhage may determine obstructive sleep apnea, even in patients without risk factors. • In the presence of clinical deterioration, clinicians should consider this complication. • Starting CPAP therapy should be assessed when treatment of elevated intracranial pressure is not indicated.

円管における隔膜の開口過程が衝撃波強さに及ぼす影響

In the present work, high-pressure hydrogen is released to air through a circular tube and shock formation process has been studied using various diaphragms separating the high-pressure hydrogen from an ambient air. To improve reproducibility of diaphragm rupture, the diaphragms were scored by precisely controlling the depths of score. The rupturing process of the ruptured diaphragm was visualized by a high-speed camera so that opening ratio of the diaphragm was estimated. As a result, the rupture pressure can be obtained with good reproducibility by selecting appropriate diaphragm material and the depth of score. Thus opening process of rupturing diaphragm and shock formation can be well controlled. The opening ratio of diaphragms was predicted by a modified equation based on previous tests of diaphragm opening in rectangular tubes. In addition, higher opening rate of diaphragms generates a stronger shock wave, whereas smaller opened area leads to a weaker shock wave.

Hydrodynamic deep drawing of double layered conical cups

Hydrodynamic deep drawing assisted by radial pressure is an advanced sheet forming technology with great advantages such as higher drawing ratio, good surface quality and higher dimensional accuracy. In this process, both the bottom surface and the peripheral edge of sheets are under hydrodynamic pressure, so that the forming procedure is more uniform with low failure probability. Multi-layered sheets with complex geometries could be formed more easily with this technique compared with other traditional methods. Rupture is the main irrecoverable failure form in sheet forming processes. Prediction of rupture occurrence is of great importance for determining and optimizing the proper process parameters. In this research, a theoretical model was proposed to calculate the critical rupture pressure in production of double layered conical parts with hydrodynamic deep drawing process assisted by radial pressure. The effects of other process parameters on critical rupture pressure, such as punch tip radius, drawing ratio, coefficient of friction, sheet thickness and material properties were also discussed. The proposed model was compared with finite element simulation and validated by experiments on Al1050/St13 double layered sheets, where a good agreement was found with analytical results.

Technological Properties of Wheat/Trifoliate Yam (Dioscorea dumetorum) Hardened Tubers Composite Flours

The ability of trifoliate hardened-yam flours to partially substitute wheat flour in food formulations was assessed. Three varieties of hardened-yam flour were incorporated in wheat flour in proportions of 0, 10, 20, 30, 40, and 50% (w/w). Samples were evaluated for protein content, Zeleny sedimentation index, Hagberg falling number, functional properties (WAC, WSI, and OAC), and some rheological properties including dough rupture pressure (P), extensibility (L), stability (P/L), and deformation energy (W). Results showed that trifoliate hardened-yam flours do not have acceptable baking properties as pictured by the low Zeleny sedimentation index and the low Hagberg falling number. Protein quality (Zeleny index, 31) of wheat flour helped to compensate gluten deficit of yam flours, but the amylasic activity determined by the Hagberg falling number could not be adjusted, which resulted in a loss of extensibility (L) of the paste at 10% substitution. Multivariate analysis of experimental data regrouped wheat flour and all wheat/hardened-yam treated with kanwa composite flours in one homogeneous cluster. Although wheat/hardened-yam treated with kanwa composite flours had physicochemical and functional properties similar to wheat, the inadequate diastasic activity makes them inappropriate for bread making, marking the strongest influence of that parameter.

Low-Salinity Chase Waterfloods Improve Performance of Cr(III)-Acetate Hydrolyzed Polyacrylamide Gel in Fractured Cores

Summary Polymer gels are frequently applied for conformance improvement in fractured reservoirs, where fluid channeling through fractures limits the success of waterflooding. Placement of polymer gel in fractures reduces fracture conductivity, thus increasing pressure gradients across matrix blocks during chase floods. A gel-filled fracture is reopened to fluid flow if the injection pressure during chase floods exceeds the gel-rupture pressure; thus, channeling through the fractures resumes. The success of a polymer-gel treatment, therefore, depends on the rupture pressure. Salinity differences between the gel network and surrounding water phase are known causes of gel swelling (e.g., observed in recent work on preformed particle gels). Gel swelling and its effect on fluid flow have, however, been less studied in conjunction with conventional polymer gels. By use of corefloods, this work demonstrates that low-salinity water can swell conventional Cr(III)-acetate hydrolyzed polyacrylamide (HPAM) gels, thereby significantly improving gel-blocking performance after gel rupture. Formed polymer gel was placed in fractured core plugs, and chase waterfloods were performed using four different brine compositions, of which three were low-salinity brines. The fluid flow rates through the matrix and differential pressures across the matrix and fracture were measured and shown to increase with decreasing salinity in the injected water phase. In some cores, the fractures were reblocked during low-salinity waterfloods, and gel-blocking capacity was increased above the initial level. Low-salinity water subsequently flooded the matrix during chase floods, which provided additional benefits to the waterflood. The improved blocking capacity of the gel was caused by a difference in salinity between the gel and injected water phase, which induced gel swelling. The results were reproducible through several experiments, and stable for long periods of time in both sandstone and carbonate outcrop core materials. Combining polymer gel placement in fractures with low-salinity chase floods is a promising approach in integrated enhanced oil recovery (IEOR).

Process analysis of hydrodynamic deep drawing of cone cups assisted by radial pressure

Forming of flat sheets into shell conical parts is a complex manufacturing process. Hydrodynamic deep drawing process assisted by radial pressure is a new hydroforming technology in which fluid pressure is applied to the peripheral edge of the sheet in addition to the sheet surface. This technique results in higher drawing ratio and dimensional accuracy, better surface quality, and ability of forming more complex geometries. In this research, a new theoretical model is developed to predict the critical rupture pressure in production of cone cups. In this analysis, Barlat–Lian yield criterion is utilized and tensile instability is considered based on the maximum load applied on the sheet. The proposed model is then validated by a series of experiments. The theoretical predictions are in good agreement with the experimental results. The effects of geometrical parameters and material properties on critical rupture pressure are also studied. The critical pressure is increased with increase in the height ratio, strain hardening exponent, and anisotropy. Higher punch nose radius expands the safe zone. It is shown that the critical pressure decreases for drawing ratios higher than 4.

Effectiveness of foam-gel formulation in homogenizing the CO2 front during subsurface sequestration

Underground sequestration of carbon dioxide uniformly all over the designated geo-formation requires use of sealant formulation in large volume. Thin channels, cracks or fractures that otherwise would have allowed a by-pass of CO2 needs to be sealed a priori. Use of a mobile hydrogel formulation that gets crosslinked over time inside the channel may be used as a sealant. Introduction of gas phase in the form of small bubbles during placement may reduce the density of the formulation, help in reaching the hard-to-reach places near the caprock, and reduce the material cost of the treatment. The surfactant and the polymer in the aqueous phase may help in stabilizing the bubbles till the cross-linked network becomes immobile for blocking unwanted flow. The paper addresses the effectiveness of foam-gel layer in sealing reservoir fractures. Partially hydrolyzed polyacrylamide was crosslinked by chromium triacetate in presence of alpha olefin sulfonate as surfactant. The introduction of gas bubbles using a fluidic arrangement, the self-alignment of bubbles on a petridish, and the alignment under the confinement of a thin channel respectively are studied here. The stability of the composite film during shut-in period, and when subjected to water or CO2 pressure were evaluated. The rupture process and the hindered flow of injected phase at the post-rupture stage were characterized. Laser based volumetric images and the pressure gradients along the channel helped in ascertaining the flow path, and intrinsic flow resistances. The foam gel layer could withstand a CO2 pressure gradient of 0.7 kg/cm2 over a length of 30.48 cm without rupture. When the pressure exceeded the rupture pressure, an aperture equivalent to 1/10th of the distance between the two walls opened up for hindered flow of CO2.

Organic cotton, lyocell and SPF: a comparative study

Purpose – The purpose of this paper is to present a comparative study on the characteristics of knitted fabrics used in the manufacturing of apparel, which are produced from organic cotton, lyocell and soybean protein fiber (SPF). It is important for both the environment and society that textile industry continues to adopt more ecofriendly materials and furthermore, pushes to increase awareness regarding these material choices available to the consumer and the corresponding impacts of consumers’ decisions. The use of sustainable fibers may be a starting point for changing the industrial paradigm of the textile industry. Design/methodology/approach – The research presented herein analyzes the potential use of three raw materials used in the development of knitted fabrics: organic cotton, lyocell and SPF. The experimental trials, based on norms, determined the weight, pilling, rupture pressure resistance, absorption by capillarity, dimensional alteration and elasticity. The significance of the experimental results was verified through the analysis of variance, with a confidence interval of 95 percent (p=0.05) and the determination of the optimal regulation of the machine was made through an analysis of the response surface. Findings – The results indicate that each of the studied materials are suitable for textile application; however, the fabrics manufactured from soybean yarn, compared to those manufactured from organic cotton or lyocell, have a higher potential to meet the needs of the costumer. Social implications – The discussion regarding sustainability is far reaching on the ways it interacts with human life. As such, the latent need for meeting this new demand presents a unique opportunity for the development of new processes and products. In the case of the textile industry, initiatives are gradually being adopted that make the processes used by the supply chain less damaging to the environment. Clothing and fashion are highly visible elements of society, so consequently, the textile industry serves as an excellent candidate for promoting a sustainable and eco-friendly mindset. Originality/value – The incorporation of sustainable fibers can serve as a starting point for change to the industrial paradigm existing within the textile industry. To this point, this study intended to analyze the potential implementation of three raw materials – organic cotton, lyocell and SPF – in the development of knitted fabrics. The results indicated that these materials are adequate for textile applications.