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.

Finite Element Simulation Analysis on Space KX-Joint

2014 ◽  
Vol 915-916 ◽  
pp. 146-149
Author(s):  
Yong Sheng Wang ◽  
Li Hua Wu
Keyword(s):  
Finite Element ◽  
Bearing Capacity ◽  
Simulation Analysis ◽  
Local Buckling ◽  
Element Model ◽  
Ansys Software ◽  
Element Simulation ◽  
Calculation Results ◽  
Buckling Failure ◽  
The Finite Element Model

The finite element model of the space KX-Joint was established using ANSYS software, and the failure mode and ultimate bearing capacity of KX-joint were researched. Calculation results show that the surface of chord wall on the roots of compression web members was into the plastic in K plane, and the holding pole without the plastic area and the local buckling failure happened in the surface of chord wall on the roots of Compression Web Members in X plane; The bearing capacity of the joint increased with the Chord diameter, which was appears in the form of power function.

Pipeline On-Bottom Stability Analysis Based on FEM Model

2011 ◽  
Author(s):  
Yong Bai ◽  
Zhimeng Yu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Design Procedure ◽  
Element Model ◽  
The Finite Element Method ◽  
Fem Model ◽  
Engineering Software ◽  
Calculation Results ◽  
Pipeline Design ◽  
Element Method

Pipeline on-bottom stability is one of the sophisticated problems in subsea pipeline design procedure. Due to the uncertainty of the pipe-soil interaction and environment loads, including wave, current, or earthquake, etc., it is classified as the typical nonlinear problem. The Finite Element Method is introduced into pipeline engineering several years ago. More and more special engineering software such as AGA, PONDUS are available in market. However, when doing a project, some abnormal data was found when compared the DnV calculation results and AGA. In order to know the behavior of pipeline on seabed under wave and current load, finite element method – ABAQUS is introduced to do this analysis. The ABAQUS/explicit is used to simulate 600s pipeline dynamic response. The pipeline is supposed to be exposed on seabed and the selected seabed model is large enough to avoid the edge effect. ABAQUS calculation results are compared with the requirements in DnV rules to verify the validity of finite element model.

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.

Creep Buckling of Ovalized Tubes Under External Pressure

1996 ◽  
Vol 118 (4) ◽  
pp. 460-463 ◽  
Author(s):  
V. Koundy ◽  
T. Forgeron ◽  
J. Hivroz
Keyword(s):  
Analytical Approach ◽  
External Pressure ◽  
The Finite Element Method ◽  
Creep Tests ◽  
Circular Tubes ◽  
Geometrical Characteristics ◽  
Calculation Results ◽  
Numerical Program ◽  
Good Agreement

In order to get a better understanding of the role of various parameters on the creep collapse phenomenon of long circular tubes, an experimental and numerical program has been undertaken. It mainly aims at studying the influence of the behavior of the material composing the circular tubes and their geometrical characteristics on the flattening time. This paper presents the results of numerical simulations performed with a specific computer program using an analytical approach. They have been compared with the data obtained from creep tests performed in various conditions on preovalized tubes as well as with the solutions obtained from the finite element method. It is shown that a good agreement is achieved between experimental results and calculation results.

scholarly journals Finite element simulation and experimental investigation of cold forward extrusion process

2018 ◽  
Vol 178 ◽  
pp. 02010 ◽  
Author(s):  
Dorin Luca
Keyword(s):  
Plastic Deformation ◽  
Finite Element ◽  
Element Model ◽  
Extrusion Process ◽  
The Finite Element Method ◽  
Forward Extrusion ◽  
Real Process ◽  
Element Simulation ◽  
Plastic Deformation Process ◽  
Good Agreement

Extrusion is the plastic deformation process that allows for the highest degree of complexity profiles to be obtained. This paper presents the simulation of a cold forward extrusion process using the finite element method. The results obtained show the stresses, strains and temperatures during the plastic deformation of the material, as well as the stresses and strains in the punch and die. The analysis of the results obtained for different geometric dimensions of the working tools allowed the optimization of the studied extrusion process. In order to validate the finite element model, experiments were carried out with the data acquisition from the real process, which allowed the appreciation that numerical and experimental data are found in a good agreement.

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.

Dynamic simulation of the relationship between pressure and displacement for the waist of elastic pantyhose in the walking process using the finite element method

2021 ◽  
pp. 004051752098174
Author(s):  
Rui Dan ◽  
Zhen Shi
Keyword(s):  
Finite Element ◽  
Human Body ◽  
Functional Relationship ◽  
External Pressure ◽  
The Body ◽  
The Finite Element Method ◽  
Element Simulation ◽  
Pressure Experiment ◽  
The Relationship ◽  
Curve Equation

The inward displacement perpendicular to body surface produced by external pressure is an important index to evaluate pressure comfort and optimal design of tight clothing products. Because of the limited pressure exerted on the human body after wearing compression clothing, the corresponding displacement is generally small, and it is difficult to obtain an accurate displacement value of the human body using general methods. In this paper, we focused on the functional relationship between pressure and displacement when the human body was in the walking state after dressing in elastic pantyhose, and then the displacement data could be easily obtained using this method. Through computerized tomography scanning, establishing of the waist cross-section, finite element simulation, and curve fitting, we finally obtained the functional relationship between the pressure/displacement ratio and angle when the body is dressed in four sample elastic pantyhose during the walking process in this study. In the formula, pressure data can be easily obtained through the pressure experiment, and the corresponding displacement value at any point of the human body can be calculated using the quadratic fitting curve equation. Results indicated that no matter what state the human body was in (static or dynamic) after wearing elastic pantyhose, the relationship between pressure and displacement at the corresponding point remains basically unchanged. That is to say, the relationship between pressure and displacement was basically not affected by the state of the human body when dressed in a tight garment. The conclusions provide an important reference for evaluating pressure comfort and optimizing clothing structure. This method is also applicable to other types of compression clothing.

Experimental and Finite Element Characterization of the Crippling Failure of Composite Stiffeners

2006 ◽  
Vol 326-328 ◽  
pp. 1773-1776
Author(s):  
Jin Hwe Kweon ◽  
Sang Min Choi ◽  
Hee Jin Son ◽  
Ji Young Choi ◽  
Jin Ho Choi ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Progressive Failure ◽  
Local Buckling ◽  
Equilibrium Path ◽  
The Finite Element Method ◽  
Progressive Failure Analysis ◽  
Good Agreement ◽  
Element Method

Progressive failure analysis based on the complete unloading method was conducted to investigate the crippling failure of carbon/epoxy composite stiffeners under axial compression. A modified arc-length algorithm was incorporated into a nonlinear finite element method to trace the equilibrium path after local buckling. For the validation of the finite element method, several carbon/epoxy Z-section stiffeners were tested in compression. The finite element results on the buckling and crippling stresses showed good agreement with the experimental results.

scholarly journals Three-dimensional Finite Element Modelling of the Cylindrical Specimen Upsetting

2018 ◽  
Vol 220 ◽  
pp. 04008 ◽  
Author(s):  
Mikhail V. Murashov ◽  
Andrey V. Vlasov
Keyword(s):  
Finite Element ◽  
Metal Forming ◽  
Three Dimensional ◽  
The Finite Element Method ◽  
Numerical Errors ◽  
Finite Element Software ◽  
Dimensional Finite Element ◽  
Calculation Results ◽  
Three Dimensional Finite Element ◽  
Good Agreement

Friction has a substantial influence on the metal forming at upsetting of cylindrical aluminum specimens. The finite element method is often used to investigate this problem. This paper aims to reveal possible numerical errors and obstacles related to the 3D finite element solution of the problem. The calculation results for the proposed numerical 3D-model are compared with the experimental data. The influence of friction is demonstrated and a good agreement on the tool displacement is obtained. The features of the numerical solution of the problem in the ANSYS finite element software are shown.

scholarly journals Study on calculation method of stability for embedded penstocks with stiffener ring under external pressure

2021 ◽  
Vol 272 ◽  
pp. 02010
Author(s):  
Bifei Wang ◽  
Yuewei Li ◽  
Wenqiang Qi ◽  
Qihang Wang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Element Model ◽  
External Pressure ◽  
Reduction Factor ◽  
Surrounding Rock ◽  
The Finite Element Method ◽  
Initial Defect ◽  
Critical External Pressure ◽  
Element Method

A three-dimensional FEM(finite element model)is established, including penstocks with initial defect (ovality), backfill concrete, drainage cushion and surrounding rock. The nonlinear static calculation of the model is carried out. The stability of penstocks with backfill concrete, drainage cushion and surrounding rock under external pressure is studied. The sensibility of the embedded penstocks to initial defect, initial gap and elastic modulus of drainage cushion is analyzed. The results of finite element method, Jacobsen method and strength formula in SL281 are compared and analyzed. The results indicate that the FEM of penstocks, backfill concrete and surrounding rock with initial defects is easy to converge by nonlinear calculation; the ovality and gap have little influence on the critical external pressure of the embedded penstocks with stiffener ring, while the drainage cushion has a certain influence on the critical external pressure; the critical external pressure calculated by SL281 is low and safe; compared with Jacobsen method, the critical external pressure of the finite element method is increased by about 14%; for the embedded penstocks with drainage cushion, the finite element method can be used to calculate the influence of the drainage cushion on the critical external pressure, and the appropriate reduction factor can be obtained, and then the Jacobsen result can be modified by the reduction factor.

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