scholarly journals Local Buckling Characteristics of Stainless-Steel Polypropylene Deep-Sea Sandwich Pipe under Axial Tension and External Pressure

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4866
Author(s):  
Jianxing Yu ◽  
Weipeng Xu ◽  
Nianzhong Chen ◽  
Sixuan Jiang ◽  
Shengbo Xu ◽  
...  
Keyword(s):  
Finite Element ◽  
Local Buckling ◽  
External Pressure ◽  
Loading Path ◽  
Finite Element Models ◽  
Collapse Pressure ◽  
Loading Paths ◽  
Axial Tension ◽  
The Difference ◽  
Good Agreement

In this paper, the effects of different loading paths of axial tension and external pressure on the collapse pressure of sandwich tubes are studied by experiments and finite element models. The difference of the two loading paths is investigated. Eight experiments were carried out to study the influence of different loading paths on pipeline collapse pressure under the same geometric and material parameters. Parameterization studies have been carried out, and the results are in good agreement with the experimental results. The test and finite element results show that the loading path of external pressure first and then the axial tension (P→T) is more dangerous; the collapse pressure of the sandwich pipe is smaller than the other. Through parametric analysis, the influence of the axial tension and the diameter-to-thickness ratio of the inner and outer pipe on the collapse pressure under different loading paths are studied.

scholarly journals Effect of Ovality Length on Collapse Strength of Imperfect Sandwich Pipes Due to Local Buckling

2021 ◽  
Vol 10 (1) ◽  
pp. 12
Author(s):  
Ruoxuan Li ◽  
Bai-Qiao Chen ◽  
C. Guedes Soares
Keyword(s):  
Finite Element ◽  
Local Buckling ◽  
Element Model ◽  
Prediction Equation ◽  
External Pressure ◽  
The Finite Element Method ◽  
Collapse Strength ◽  
Calculation Results ◽  
The Relationship ◽  
Good Agreement

The effect of ovality length on imperfect sandwich pipes is investigated using the finite element method in the scenario of local buckling under external pressure. First, the finite element model of the imperfect sandwich pipelines is established in ANSYS and is validated by comparing the results from numerical simulation with those from experiments. Then, the effect of ovality features on the collapse strength of the sandwich pipes is studied. At last, based on the calculation results from 1200 cases, a prediction equation is proposed to represent the relationship between collapse strength and ovality length of imperfect sandwich pipes. Good agreement is achieved between the proposed equation and the calculation results, leading to the conclusion that the proposed simplified model can be an efficient tool in the evaluation of the local collapse strength of subsea sandwich pipes under external pressure.

Simplified Finite Element Models to Study the Wet Collapse of Straight and Curved Flexible Pipes

2017 ◽  
Vol 139 (6) ◽  
Author(s):  
Alfredo Gay Neto ◽  
Clóvis de Arruda Martins ◽  
Eduardo Ribeiro Malta ◽  
Rafael Loureiro Tanaka ◽  
Carlos Alberto Ferreira Godinho
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
3D Models ◽  
External Pressure ◽  
Finite Element Models ◽  
Flexible Pipe ◽  
Collapse Pressure ◽  
Flexible Pipes ◽  
Polymeric Layer ◽  
Collapse Failure

When the external sheath of flexible pipes experiences damage, seawater floods the annulus. Then, the external pressure is applied directly on the internal polymeric layer, and the load is transferred to the interlocked carcass, the innermost layer. In this situation, the so-called wet collapse failure of the interlocked carcass can occur. Simplified methodologies to address such a scenario, using restricted three-dimensional (3D) finite element models, are presented in this work. They are compared with full 3D models, studying both straight and curved flexible pipes scenarios. The curvature of the flexible pipe is shown to be important for wet collapse pressure predictions.

Collapse of Tubes Under Combined Bending and Axial Compression Loads

2018 ◽  
Author(s):  
Shan Jin ◽  
Shuai Yuan ◽  
Yong Bai
Keyword(s):  
Mechanical Properties ◽  
Finite Element Method ◽  
Finite Element ◽  
Axial Compression ◽  
Local Buckling ◽  
Practical Application ◽  
Buckling Modes ◽  
Combined Loads ◽  
Bending Loads ◽  
Good Agreement

In practical application, pipelines will inevitably experience bending and compression during manufacture, transportation and offshore installation. The mechanical behavior of tubes under combined axial compression and bending loads is investigated using experiments and finite element method in this paper. Tubes with D/t ratios in the range of 40 and 97 are adopted in the experiments. Then, the ultimate loads and the local buckling modes of tubes are studied. The commercial software ABAQUS is used to build FE models to simulate the load-shortening responses of tubes under combined loads. The results acquired from the ABAQUS simulation are compared with the ones from verification bending experiment, which are in good agreement with each other. The models in this paper are feasible to analyze the mechanical properties of tubes under combined axial compression and bending loads. The related results may be of interest to the manufacture engineers.

Strains and Deflections of GFRP Sandwich Panels Due to Uniform Out-of-Plane Pressure

2002 ◽  
Vol 39 (04) ◽  
pp. 223-231
Author(s):  
J. C. Roberts ◽  
M. P. Boyle ◽  
P. D. Wienhold ◽  
E. E. Ward
Keyword(s):  
Finite Element ◽  
Compressive Strain ◽  
Sandwich Panels ◽  
External Pressure ◽  
Woven Fabric ◽  
Core Material ◽  
Finite Element Models ◽  
Strain Gages ◽  
Glass Fiber Reinforced Plastic ◽  
Out Of Plane

Rectangular orthotropic glass fiber reinforced plastic sandwich panels were tested under uniform out-of-plane pressure and the strains and deflections were compared with those from finite-element models of the panels. The panels, with 0.32 cm (0.125 in.) face sheets and a 1.27 cm (0.5 in.)core of either balsa or linear polyvinylchloride foam, were tested in two sizes: 183 × 92 cm (72 × 36 in.) and121 × 92 cm (48 × 36 in.). The sandwich panels were fabricated using the vacuum-assisted resin transfer molding technique. The two short edges of the sandwich panels were clamped, while the two long edges were simply supported. Uniform external pressure was applied using two large water inflatable bladders in series. The deflection and strains were measured using dial gages and strain gages placed at quarter and half points on the surface of the panels. Measurements were made up to a maximum out-of-plane pressure of 0.1 MPa (15psi). A total of six balsa core and six foam core panels were tested. Finite-element models were constructed for the 183-cm-long panel and the121-cm-long panel. Correlation between numerical and experimental strains to deflect the sandwich panel was much better on the top (tensile) side of the panels than on the bottom (compressive)side of the panels, regardless of panel aspect ratio or core material. All sandwich panels exhibited the same compressive strain reversal behavior on the compressive side of the panel. This phenomenon was thought to be due to nonlinearly induced micro-buckling under the strain gages, buckling of the woven fabric, or micro-cracking within the resin.

Collapse Arrestors for Deepwater Pipelines: Finite Element Models and Experimental Validations for Different Cross-Over Mechanisms

2006 ◽  
Author(s):  
Rita G. Toscano ◽  
Luciano O. Mantovano ◽  
Pablo Amenta ◽  
Roberto Chareau ◽  
Daniel Johnson ◽  
...  
Keyword(s):  
Finite Element ◽  
Experimental Validation ◽  
Numerical Models ◽  
External Pressure ◽  
Finite Element Models ◽  
The Cross ◽  
Experimental Validations

Using finite element models it is possible to determine the cross-over external pressure of different pipeline arrestor designs. In this paper these finite element models are discussed and validated by comparing their results with experimental determinations. The flipping and flattening cross-over mechanisms are considered in the experimental validation of the numerical models.

Research of Reinforce Stress on the Pressure Structure of Submersible Vehicle

2014 ◽  
Vol 496-500 ◽  
pp. 590-593
Author(s):  
Guan Nan Chu ◽  
Qing Yong Zhang ◽  
Guo Chun Lu
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stress Distribution ◽  
Hoop Stress ◽  
External Pressure ◽  
Finite Element Models ◽  
Cylinder Pressure ◽  
Simulation Experiments ◽  
Element Analysis ◽  
Load Carrying

In order to improve the load-carrying properties of pressure structure, a new method to improve the external bearing limit is put forward and residual stress is used. Based on finite element analysis, finite element models of cylinder pressure structure of submersible vehicle are established to produce hoop residual stress in the process of outward expansion. According to a lot of data of simulation experiments, the result indicates that hoop residual stress is compressive on the outer surface of the pipe and the hoop stress keeps tensile on the inside surface. This kind of stress distribution is helpful to the cylinder structure and can improve its bearing capacity of external pressure. Moreover, the rules of the residual stress are got. The influences of physical dimension, yield strength of material and the expansion rate to the stress distribution are analyzed. The measures to produce the stress distribution are also presented.

Comparison of Two Approaches to Model Cure-Induced Microcracking in Three-Dimensional Woven Composites

2012 ◽  
Author(s):  
Igor Tsukrov ◽  
Michael Giovinazzo ◽  
Kateryna Vyshenska ◽  
Harun Bayraktar ◽  
Jon Goering ◽  
...  
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Volume Fraction ◽  
Three Dimensional ◽  
Woven Composites ◽  
Finite Element Models ◽  
The Matrix ◽  
3D Woven Composites ◽  
The Difference ◽  
Resin Curing

Finite element models of 3D woven composites are developed to predict possible microcracking of the matrix during curing. A specific ply-to-ply weave architecture for carbon fiber reinforced epoxy is chosen as a benchmark case. Two approaches to defining the geometry of reinforcement are considered. One is based on the nominal description of composite, and the second involves fabric mechanics simulations. Finite element models utilizing these approaches are used to calculate the overall elastic properties of the composite, and predict residual stresses due to resin curing. It is shown that for the same volume fraction of reinforcement, the difference in the predicted overall in-plane stiffness is on the order of 10%. Numerical model utilizing the fabric mechanics simulations predicts lower level of residual stresses due to curing, as compared to nominal geometry models.

Effect of Steel Properties on Buckling Pressure of Corroded Pipelines

2017 ◽  
Vol 898 ◽  
pp. 741-748 ◽  
Author(s):  
Meng Li ◽  
Hong Zhang ◽  
Meng Ying Xia ◽  
Kai Wu ◽  
Jing Tian Wu ◽  
...  
Keyword(s):  
Finite Element ◽  
Yield Strength ◽  
Strain Hardening ◽  
Corrosion Damage ◽  
Element Model ◽  
External Pressure ◽  
Strain Hardening Exponent ◽  
The Finite Element Method ◽  
Collapse Pressure ◽  
Steel Properties

Due to the harsh environment for submarine pipelines, corrosion damage of the pipeline steels is inevitable. After the corrosion damage, pipelines are prone to failure and may cause serious consequences. The analysis of the effects of different steel properties on the collapse pressure of pipelines with corrosion defects is of importance for the option of appropriate pipeline and avoiding accidents. Based on the finite element method, the finite element model of the pipeline with defects under external pressure was built. Firstly, the accuracy of the numerical model was validated by comparing with previous experimental results. The effects of yield strength and strain hardening exponent on collapse pressure of pipelines with different sizes of defect were discussed in detail. Results showed that the yield strength and strain hardening exponent have different influences on collapse pressure: the collapse pressure increases with the increasing yield strength, and the collapse pressure decreases with the increasing strain hardening exponent.

Contribution of Gear Body to Tooth Deflections—A New Bidimensional Analytical Formula

2004 ◽  
Vol 126 (4) ◽  
pp. 748-752 ◽  
Author(s):  
P. Sainsot and ◽  
P. Velex ◽  
O. Duverger
Keyword(s):  
Finite Element ◽  
Analytical Formula ◽  
Constant Stress ◽  
Finite Element Models ◽  
Gear Dynamics ◽  
Computer Codes ◽  
Stress Variations ◽  
Tooth Pair ◽  
Good Agreement

The magnitude and variation of tooth pair compliance affects tooth loading and gear dynamics significantly. This paper presents an improved fillet/foundation compliance analysis based on the theory of Muskhelishvili applied to circular elastic rings. Assuming linear and constant stress variations at root circle, the above theory makes it possible to derive an analytical formula for gear body-induced tooth deflections which can be directly integrated into gear computer codes. The corresponding results are in very good agreement with those from finite element models and the formula is proved to be superior to Weber’s widely used equation, especially for large gears.

Enhanced Design Criteria for Offshore Pipeline Integral Buckle Arrestors

2008 ◽  
Author(s):  
L.-H. Lee ◽  
S. Kyriakides ◽  
T. A. Netto
Keyword(s):  
Finite Element ◽  
Thick Wall ◽  
Design Criteria ◽  
Finite Element Models ◽  
Design Formula ◽  
Offshore Pipeline ◽  
Deformation Plasticity ◽  
The Difference ◽  
Buckle Arrestors ◽  
Empirical Design

Integral buckle arrestors are relatively thick-wall rings periodically welded in an offshore pipeline at intervals of several hundred meters in order to safeguard the line in the event a propagating buckle initiates. They provide additional circumferential rigidity and thus impede downstream propagation of collapse, limiting the damage to the length of pipe separating two arrestors. The effectiveness of such devices was studied parametrically through experiment and numerical simulations in Park and Kyriakides [2]. The experiments involved quasi-static propagation of collapse towards an arrestor, engagement of the arrestor, temporary arrest, and the eventual crossing of collapse to the downstream pipe at a higher pressure. The same processes were simulated with finite element models that included finite deformation plasticity and contact. The experimental crossover pressures enriched with numerically generated values were used to develop an empirical design formula for the arresting efficiency of such devices. A recent experimental extension of this work revealed that for some combinations of arrestor and pipe yield stresses the design formula was overly conservative. Motivated by this finding, a new broader parametric study of the problem was undertaken which demonstrated that the difference between the pipe and arrestor yield stress affects significantly the arrestor performance. The original arrestor design formula was then modified to include the new experimental and numerical results producing an expression with a much wider applicability.

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