Burst Pressure Prediction Research Articles

Burst pressure prediction of Type IV hydrogen vessel by meso-scale simulation

The meso-scale simulation, where the carbon fiber bundle structure with resin is explicitly handled, seems promising for rational setting of burst criteria of Type IV hydrogen vessel. Material properties including fracture models both for carbon fiber and resin can be directly introduced. The stress and strain concentrations caused by fiber bundles crossing are adequately analyzed to predict burst pressure in terms of carbon fiber strain. The advantage of the proposed methodology is demonstrated by the numerical example and future possibility is discussed.

Double circular arc model based on average shear stress yield criterion and its application in the corroded pipe burst

Corrosion is one of the major causes of damage in offshore and onshore pipes. Based on the double circular arc (DCA) model and the average shear stress yield (ASSY) criterion for isotropic hardening materials, a new burst pressure equation for corroded pipes is developed in this paper. The ASSY criterion is a weighted average of the maximum shear stress and the octahedral shear stress and it is adopted to predict the burst pressure of the pipelines with corrosion defects. The accuracy of our predictive equations is validated respectively by both the ideal and corroded pipes. Firstly, the burst pressure equation of a corroded pipe is degraded into an ideal pipe's. Then we compare the calculated results with the full-scale experimental data. The calculated results are consistent with the experimental data for the ideal pipes. Again, we make a comparison of the predicted burst pressures of corroded pipes with the ones from the elastic-plastic finite element method (FEM) and the experiment. The calculated results show a good agreement with the numerical calculations and experimental data for the corroded pipes. Our research reveals that the corrosion defects can decrease the burst pressure for a pipe; the yield criterion and the strain hardening exponent are crucial to accurately capture the burst pressure. Our research is beneficial to evaluate the integrity of the corroded pipes.

Integrity assessment of API X70 pipe with corroded girth and seam welds via numerical simulation and burst test experiments

Abstract Welded pipes containing corrosion may lead to catastrophic situations during transportation of gas. Appropriate methods are needed to assess defective pipelines for integrity assessment. Corroded girth and seam welds were studied for the effect of corrosion length and depth on the burst pressure of API X70 pipe. Full-scale hydrostatic burst pressure tests and finite element analysis (FEA) were performed to investigate the burst pressure resulting from the corroded girth and seam welds. The experimental results were used to validate the finite element model, which considered the 3D elastic–plastic behavior. The FEA predicted burst pressures were compared with the ASME B31G, Modified ASME B31G, DNV RP-F101, and PCORRC standards in order to derive a proper equation for evaluation of corroded seam and girth welds.

Progressive Failure Analysis of Pipeline Repaired by Composite Wrapping

Composite overwrap systems have been widely used to repair damaged pipelines. Its effectiveness has been proven by many researches and engineering applications. However, the research on progressive failure mode of the repaired structure has not been reported. In the present paper, finite element method with Hashin failure criteria is developed to realize the progressive failure analysis. The predicted burst pressure is in good agreement with the burst experiment. Different from widely-reported failure progress in Composite Overwrapped Pressure Vessels (COPV), the progressive failure analysis for the defected pipeline overwrapped by composite reveals very different failure stages: stable failure propagation and rapid failure propagation. The identification of critical pressure between these two stages is valuable in composite reparation design for the defected pipeline.

Finite element analysis to estimate burst pressure of mild steel pressure vessel using Ramberg–Osgood model

Summary Burst pressure is the pressure at which vessel burst/crack and internal fluid leaks. An accurate prediction of burst pressure is necessary in chemical, medical and aviation industry. Burst pressure is a design safety limit, which should not be exceeded. If this pressure is exceeded it may lead to the mechanical breach and permanent loss of pressure containment. So burst pressure calculation is necessary for all the critical applications. To numerically calculate burst pressure material curve is essential. There are various material models which are used to define material curve, amongst them Ramberg–Osgood is very popular. Ramberg–Osgood accurately capture material curve in strain hardening region. This approach is applicable for different material grades. In this paper a finite element method is used to predict burst pressure using Ramberg–Osgood equation. These results are then compared with results obtained from elasto-plastic curve and true stress strain curve. Results obtained by finite element analysis are validated with experimental data which is considered from open literature.

Determination of Limit Load Solution for the Remaining Load-Carrying Capacity of Corroded Pipelines

The evaluation of pipelines having external corrosion defect and their remaining load-carrying capacity is a concern which becomes important in energy industry, especially with the increasing operating pressures and the consequences which can occur following the bursting of these pipelines. A lower bound analytical solution for the prediction of the burst pressure of pipelines is proposed. This solution is based on the approach of plastic-instability criterion in terms of material strain-hardening exponent of internally pressurized corroded pipelines. The suggested solution is evaluated by using database comprising more than 100 carried out tests of pipelines with or without corrosion defects. This database is collected from the literature and covers the majority of steel materials as well as the various standard sizes. The accuracy of the proposed solution is compared with B31.G method and its improved version B31.G Mod by using statistical analyses in terms of average error and its correspondent standard deviation. The proposed solution is accurate than B31.G and modified B31.G methods that are conservative and provide in some cases of middle and high strength material an overestimated burst pressure predictions.

Prediction of Burst Pressure in Multistage Tube Hydroforming of Aerospace Alloys.

Bursting, an irreversible failure in tube hydroforming (THF), results mainly from the local plastic instabilities that occur when the biaxial stresses imparted during the process exceed the forming limit strains of the material. To predict the burst pressure, Oyan's and Brozzo's decoupled ductile fracture criteria (DFC) were implemented as user material models in a dynamic nonlinear commercial 3D finite-element (FE) software, ls-dyna. THF of a round to V-shape was selected as a generic representative of an aerospace component for the FE simulations and experimental trials. To validate the simulation results, THF experiments up to bursting were carried out using Inconel 718 (IN 718) tubes with a thickness of 0.9 mm to measure the internal pressures during the process. When comparing the experimental and simulation results, the burst pressure predicated based on Oyane's decoupled damage criterion was found to agree better with the measured data for IN 718 than Brozzo's fracture criterion.

Prediction of Burst Pressure of Pipes With Geometric Eccentricity

An analytical model was proposed in this paper to predict the burst pressure of a pipe with geometric eccentricity. With application of the complex elastic potential function method in a bipolar coordinate system, the authors first derived an analytical solution of stresses in an eccentric pipe and then obtained the formula of predicting burst pressure by combining the solution with the Tresca criterion. Finally, the effect of eccentricity and the ratio of thickness to diameter of pipe on burst pressure were discussed. Our results show that a slight eccentricity can significantly decrease the burst pressure. In the special case of zero-eccentricity for a concentric pipe, our model yields results that are consistent with experiments data published by others and theoretical results predicted by models proposed by other researchers without considering the effect of eccentricity. In the case of eccentricity for an eccentric pipe, the calculating results of our model are also consistent with that of finite element model (FEM). The theoretical model and results presented in this paper have a broader application in predicting the burst pressure for pipes commonly used in oil and gas industry.

Burst pressure analysis of pipes with geometric eccentricity and small thickness-to-diameter ratio

Abstract Two analytical models were proposed to predict the burst pressure of pipes characterized by a small thickness-to-diameter ratio and geometric eccentricity. Based on a complex stress function in a bipolar coordinate system, an analytical solution was derived for the stresses of an internally pressurized eccentric pipe, and two burst pressure prediction formulae for restrained and end-capped pipe models were obtained according the von Mises stress, which took the ultimate tensile strength (UTS) of the inner wall as the pipe bursting criterion. Next these formulae were validated by comparing the results obtained with the results of existing elastic–plastic formulae and a nonlinear finite element method. Finally, the effect of eccentricity on the burst pressure was evaluated and simplified as an empirical formula. Our research shows that the burst pressure of restrained and end-capped pipes with geometric eccentricity are nearly equivalent, and the burst pressure of an eccentric pipe is relative to that of a non-eccentric pipe. The theoretical and empirical formulae presented in this paper have broad application in the oil and gas industry to predict the burst pressure of pipes.

Model error assessment of burst capacity models for energy pipelines containing surface cracks

This paper develops the probabilistic characteristics of the model errors associated with five well-known burst capacity models/methodologies for pipelines containing longitudinally-oriented external surface cracks, namely the Battelle and CorLAS™ models as well as the failure assessment diagram (FAD) methodologies recommended in the BS 7910 (2005), API RP579 (2007) and R6 (Rev 4, Amendment 10). A total of 112 full-scale burst test data for cracked pipes subjected internal pressure only were collected from the literature. The model error for a given burst capacity model is evaluated based on the ratios of the test to predicted burst pressures for the collected data. Analysis results suggest that the CorLAS™ model is the most accurate model among the five models considered and the Battelle, BS 7910, API RP579 and R6 models are in general conservative; furthermore, the API RP579 and R6 models are markedly more accurate than the Battelle and BS 7910 models. The results will facilitate the development of reliability-based structural integrity management of pipelines.

Burst pressure of super duplex stainless steel pipes subject to combined axial tension, internal pressure and elevated temperature

The burst pressure of super duplex stainless steel pipe is measured under combined internal pressure, external axial tension and elevated temperature up to 160 °C. The experimental results are compared with existing burst pressure prediction models. Existing models are found to provide reasonable estimate of the burst pressure at room temperature but significantly over estimate the burst pressure at elevated temperature. Increasing externally applied axial stress and elevated temperature reduces the pressure capacity.

Burst Pressure Prediction of Multiple Cracks in Pipelines

Available industrial code such as ASME B1G, modified ASME B1G and DNV RP-F101 to assess pipeline defects appear more conservative for multiple crack like- defects than single crack-like defects. Thus, this paper presents burst pressure prediction of pipe with multiple cracks like defects. A finite element model was developed and the burst pressure prediction was compared with the available code. The model was used to investigate the effect of the distance between the cracks and the crack length. The coalescence diagram was also developed to evaluate the burst pressure of the multiple cracks. It was found as the distance between crack increases, the interaction effect comes to fade away and multiple cracks behave like two independent single cracks.

The impact of atherosclerosis and vascular collagen on energy-based vessel sealing

BackgroundBipolar energy ligation of vessels in surgery is common. Although rare, serious failures occur. Atherosclerosis may contribute to seal failures by altering vascular compressibility and collagen content; however, no data exist. Materials and methodsFemoral and iliac arteries of six Yucatan swine with an identified genetic locus predisposing them to atherosclerosis were denuded with a Fogarty catheter. Animals were fed a high-fat diet for 28 wk. A Yorkshire pig was used as a normal control and fed a standard diet. At 28 wk, arteries were measured for their diameters, sealed, and divided in vivo with LigaSure. The sealed artery sections were excised and subjected to burst pressure testing. Half of the seal distal to the aorta was kept intact for histology and collagen and elastin quantification. A multiple linear regression model was used to assess variables contributing to burst pressure. Covariates included were vessel diameter, degree of atherosclerosis, and collagen content. ResultsExperimental animals were hypercholesterolemic. Atherosclerosis occurred in 90% of seals in induced animals, with severe atherosclerosis in 62% of seals. There was site-selective deposition of atherosclerotic plaques in larger diameter iliac vessels. A model including collagen and size best predicted burst pressure. Every 10-U increase in collagen resulted in 15% increase in burst pressure (95% confidence interval = 0.2%–32%, P = 0.047, R2 = 0.36). Atherosclerosis was unrelated to burst pressure controlling for collagen and size. ConclusionsCollagen and size provide the best model fit for predicting burst pressure. Quantitative research in human vasculature is warranted to better understand the influence of atherosclerosis and collagen content on seal failures.

Mechanical Behavior of Internally Pressurized Copper Tube for New HVACR Applications

This paper reviews and simplifies basic theory to predict plastic strain and burst pressure of internally pressurized, thin-walled copper tube for (heating, ventilation, air conditioning, and refrigeration applications. Predictions are based upon material stress–strain data obtained from basic tensile tests. A series of pressure tests was performed at 635 to 1500 psi (4.38–10.34 MPa), and until burst, on tubes ranging from 0.625 in. (15.87 mm) to 2.125 in. (53.97 mm) in diameter. A Voce type equation is shown to provide superior correlation to tensile and instability data, such that accurate projections can be made. An assessment of the classical power-law (Ludwik–Hollomon) equation is also presented, and it did not simultaneously correlate well with stress–strain data and satisfy the Considère instability criterion in uni-axial tension. Nevertheless, its use still led to reasonably accurate burst pressure predictions due to the strain range over which it was applied. Property variation (with respect to tube size) and anisotropy were observed in the transverse and axial tube directions for 1.125 in. (28.6 mm) and 2.125 in. (54.0 mm) diameter tube. Thus, the importance of representative and accurate material data in the transverse (hoop) direction is emphasized.

Model error assessments of burst capacity models for corroded pipelines

The model errors associated with eight well-known burst capacity models for corroded pipelines, namely B31G, B31G Modified, CPS, the CSA model, the DNV model, PCORRC, RSTRENG and SHELL92, are characterized based on a full-scale burst test database that consists of 150 data points collected from the literature for pipe specimens containing single isolated real corrosion defects. The probabilistic characteristics of the model errors, including the mean values, coefficients of variation and probability distributions, for the burst models are obtained by analyzing the ratios between the test and predicted burst pressures corresponding to the test data applicable to the model. For each of the burst models, separate model errors for short and long defects are also evaluated, whereby the short and long defects are separated by the transition normalized defect length that is identified using the weighted average COV approach.

Study of True Stress-Strain Curve after Necking for Application in Ductile Fracture Criteria in Tube Hydroforming of Aerospace Material

Tube hydroforming (THF) is an advanced metal forming process that is used widely in automotive industry, but the application of the THF process in aerospace field is comparatively new with many challenges due to high strength and limited formability of aerospace materials. The success of THF process largely depends on many factors, such as mechanical properties of the material, loading path during the process, tool geometry and friction condition. Due to complexity of this process, finite element modeling (FEM) can largely reduce the production cost. One of the important input in FEM is the material behavior during hydroforming process. The true stress-strain curve before necking can be easily determined, using either tensile testing or bulge testing, but for an accurate failure prediction in a large deformation, such as hydroforming, the study of true stress-strain curve after necking is important because it improves the quality of the analysis due to utilizing a real extended stress-strain curve. Hence, the objective of this research was to establish a methodology to determine the true stress-strain curve after necking in order to predict burst pressure in the THF of aerospace materials. Uniaxial tensile tests were performed on standard tensile samples (ASME E8M-04) to determine the true stress-strain before and after necking, using an analytical method presented in this study. To validate the approach, burst pressure in the THF process was predicted using the extended stress-strain curve in conjunction with Brozzo's decoupled fracture model. The approach was evaluated using data obtained from the free expansion (tube bulging) tests performed on stainless steel 321 tubes with 2 inches diameter and two different thicknesses, 0.9 mm and 1.2 mm. The comparison of the predicted and measured burst pressures was promising, indicating that the approach has the potential to be extended to predict formability limits in THF of complex shapes.

Neural Network Burst Pressure Prediction in Composite Overwrapped Pressure Vessels Using Mathematically Modeled Acoustic Emission Failure Mechanism Data

The purpose of this research was to predict burst pressures in composite overwrapped pressure vessels (COPVs) by using mathematically modeled acoustic emission (AE) data. Both backpropagation neural network (BPNN) and multiple linear regression (MLR) analyses were performed on various subsets of the low proof pressure AE data to predict burst pressures and to determine if the two methods were comparable. AE data were collected during hydrostatic burst testing on the 15-inch diameter COPVs. Once collected, the AE data were filtered to eliminate noise then classified into AE failure mechanism data using a MATLAB Kohonen self-organizing map (SOM). The matrix cracking only amplitude distribution data were mathematically modeled using bounded Johnson distributions with the four Johnson distribution parameters – ϵ, λ, γ, and η – employed as inputs to make both the BPNN and MLR predictions. The burst pressure predictions generated using a MATLAB BPNN resulted in a worst case error of 1.997% as compared to −1.666% for the MLR analysis, suggesting comparability. However, the MLR analysis required the data from all nine COPVs to get approximately the same results as the BPNN training on just five COPVs; plus, MLR analyses are intolerant to noise, whereas BPNNs are not.

Evaluation of burst pressure prediction models for line pipes

Accurate prediction of burst pressure plays a central role in engineering design and integrity assessment of oil and gas pipelines. Theoretical and empirical solutions for such prediction are evaluated in this paper relative to a burst pressure database comprising more than 100 tests covering a variety of pipeline steel grades and pipe sizes. Solutions considered include three based on plasticity theory for the end-capped, thin-walled, defect-free line pipe subjected to internal pressure in terms of the Tresca, von Mises, and ZL (or Zhu-Leis) criteria, one based on a cylindrical instability stress (CIS) concept, and a large group of analytical and empirical models previously evaluated by Law and Bowie (International Journal of Pressure Vessels and Piping, 84, 2007: 487–492). It is found that these models can be categorized into either a Tresca-family or a von Mises-family of solutions, except for those due to Margetson and Zhu-Leis models. The viability of predictions is measured via statistical analyses in terms of a mean error and its standard deviation. Consistent with an independent parallel evaluation using another large database, the Zhu-Leis solution is found best for predicting burst pressure, including consideration of strain hardening effects, while the Tresca strength solutions including Barlow, Maximum shear stress, Turner, and the ASME boiler code provide reasonably good predictions for the class of line-pipe steels with intermediate strain hardening response.

Finite element analysis of aircraft tyre – Effect of model complexity on tyre performance characteristics

A brief study on the complexity of the structure of aircraft tyres is presented. The main goal is to investigate how complexity of Finite element (FE) models of the tyre can affect the simulation behaviour with respect to accurate prediction of real tyre behaviour. Three FE models, so called “simple”, “regular” and “complex” were developed for this investigation so that the accuracy of results obtained from the models for different types of analysis can be determined in comparison with measured test data. For all the simulations carried out, including tyre burst test and tyre inflation, a hyperelastic material property was assumed for modelling rubber and cord materials, using the Yeoh model [1]. Simulations were performed using Abaqus/CAE for two dimensional (2D) analysis and Abaqus command line partly for three dimensional (3D) simulation of tyre inflation. Physical tests were carried out on two tyres for FE model validation in terms of tyre burst test and profile sizing measurements. The results showed excellent accuracy in terms of deformation in FE models by comparison with real size measurements of tyre profiles. Also, a quite good prediction of tyre burst pressure under high inflation was obtained for the different models. Finally, the investigation showed that while maximum stress in cords and maximum deflection of tyres at the rated inflation pressure were fairly insensitive to varying the mesh size in the FE models, maximum stress in the rubber components was particularly sensitive to such mesh size variation.

Burst Pressure Prediction of Composite Pressure Chambers Using Acoustic Emission Technique: A Review

Over the last four to five decades, applications of fiber-reinforced plastics (FRP) have seen tremendous growth. In spite of the complexity of their behavior, development of composite pressure chambers has significantly contributed to the continuing increase in the strength-to-weight ratio of a significant amount of hardware and testing techniques to evaluate that hardware are continually being developed. This article presents an overview of the developments toward burst pressure prediction of FRP pressure chambers using acoustic emission (AE) technique. Burst strength prediction methods and related research in this context are also briefly discussed. The historical background of FRP pressure chamber/vessel testing using AE is also covered in this review.