Plastic Collapse of API 5L X65 Pipe Having Dent Defects Under Internal Pressure and Bending Load

2010 ◽  
Author(s):  
Jong-hyun Baek ◽  
Young-pyo Kim ◽  
Cheol-man Kim ◽  
Woo-sik Kim ◽  
Jae-mean Koo ◽  
...  
Keyword(s):  
Internal Pressure ◽  
Carrying Capacity ◽  
Bending Moment ◽  
Plastic Collapse ◽  
Load Carrying Capacity ◽  
Combined Load ◽  
Bending Mode ◽  
Load Carrying ◽  
Collapse Behavior ◽  
Dent Depth

The objective of this study was to investigate the effect of the dent magnitude on the collapse behavior of dented pipe subjected to a combined internal pressure and in-plane bending. The plastic collapse behavior and bending moment of the dented pipe with several of dent dimensions were evaluated by using elastic–plastic finite element (FE) analyses. The indenters used to manufacture the dents on the API 5L X65 pipe were hemispherical rod type with diameter of 40, 80, 160 and 320 mm. Dent depths of 19, 38, 76, 114 and 152 mm were introduced on the pipe having a diameter of 762 mm and a wall thickness of 17.5 mm in analyses. A closing or opening inplane bending moment was applied on the dented pipes pressurized under internal pressure of the atmospheric pressure, 4, 8 and 16 MPa. The FE analyses results showed that the plastic collapse behavior of dented pipes was considerably governed by the bending mode and the dent geometry. Moment-bending angle curves for dented pipe were obtained from computer simulation and evaluated with a variety of factors in FE analyses. Load carrying capacity of dented pipes under combined load was evaluated by TES (Twice Elastic Slope) moments. Load carrying capacity of pipe having up to 5% dent depth of outer diameter was not reduced compared with that of plain pipe. Opening bending mode had a higher load carrying capacity than closing bending mode under combined load regardless of dent depth. TES moment was decreased with increasing the dent depth and internal pressure regardless of bending modes.

Influence of Yield Strength Variability over Cross-Section to Steel Beam Load-Carrying Capacity

2005 ◽  
Vol 10 (2) ◽  
pp. 151-160 ◽  
Author(s):  
J. Kala ◽  
Z. Kala
Keyword(s):  
Yield Strength ◽  
Cross Section ◽  
Carrying Capacity ◽  
Bending Moment ◽  
Statistical Characteristics ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Strength Variability ◽  
Hot Rolled ◽  
Hot Rolled Steel

Authors of article analysed influence of variability of yield strength over cross-section of hot rolled steel member to its load-carrying capacity. In calculation models, the yield strength is usually taken as constant. But yield strength of a steel hot-rolled beam is generally a random quantity. Not only the whole beam but also its parts have slightly different material characteristics. According to the results of more accurate measurements, the statistical characteristics of the material taken from various cross-section points (e.g. from a web and a flange) are, however, more or less different. This variation is described by one dimensional random field. The load-carrying capacity of the beam IPE300 under bending moment at its ends with the lateral buckling influence included is analysed, nondimensional slenderness according to EC3 is λ¯ = 0.6. For this relatively low slender beam the influence of the yield strength on the load-carrying capacity is large. Also the influence of all the other imperfections as accurately as possible, the load-carrying capacity was determined by geometrically and materially nonlinear solution of very accurate FEM model by the ANSYS programme.

An Experimental Study on the Evaluation of Failure Behavior of Pipe With Local Wall Thinning

2002 ◽  
Author(s):  
Jin Weon Kim ◽  
Chi Yong Park
Keyword(s):  
Internal Pressure ◽  
Failure Mode ◽  
Carrying Capacity ◽  
Axial Length ◽  
Failure Behavior ◽  
Load Carrying Capacity ◽  
Wall Thinning ◽  
Load Carrying ◽  
Deformation Ability ◽  
Local Wall Thinning

The pipe failure tests were performed using 102mm-Sch.80 carbon steel pipe with various simulated local wall thinning defects, in the present study, to investigate the failure behavior of pipe thinned by flow accelerated corrosion (FAC). The failure mode, load carrying capacity, and deformation ability were analyzed from the results of experiments conducted under loading conditions of 4-point bending and internal pressure. A failure mode of pipe with a defect depended on the magnitude of internal pressure and axial thinning length as well as stress type and thinning depth and circumferential angle. Also, the results indicated that the load carrying capacity and deformation ability were depended on stress state in the thinning region and dimensions of thinning defect. With increase in axial length of thinning area, for applying tensile stress to the thinning region, the dependence of load carrying capacity was determined by circumferential thinning angle, and the deformation ability was proportionally increased regardless of the circumferential angle. For applying compressive stress to thinning region, however, the load carrying capacity was decreased with increase in axial length of the thinned area. Also, the effect of internal pressure on failure behavior was characterized by failure mode of thinned pipe, and it promoted crack occurrence and mitigated a local buckling of the thinned area.

Experimental Study on the Collapse Strength of Narrow Stiffened Panels

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
Ming Cai Xu ◽  
C. Guedes Soares
Keyword(s):  
Carrying Capacity ◽  
Longitudinal Direction ◽  
Strain Gauges ◽  
Load Carrying Capacity ◽  
Stiffened Panels ◽  
Modes Of Failure ◽  
Collapse Strength ◽  
Tension Tests ◽  
Load Carrying ◽  
Collapse Behavior

The results of five tests on narrow stiffened panels under axial compression until collapse and beyond are presented to investigate the collapse behaviors of stiffened panels. Tension tests were used to evaluate the material properties of the stiffened panels. The tests were made on panels with two half bays plus one full bay in the longitudinal direction. Initial loading cycles were used to eliminate the residual stresses of the stiffener panels. The strain gauges were set on the plates and the stiffeners to record the strain histories. The displacement load relationship was established. The collapse behavior, modes of failure and load-carrying capacity of the stiffened panels are investigated with the experiment.

scholarly journals Technological increase of static load carrying capacity of local raceways in ball bearings through ball rolling-off

2018 ◽  
Vol 2018 (12) ◽  
pp. 28-32
Author(s):  
Альберт Королев ◽  
Albert Korolev ◽  
Михаил Захарченко ◽  
Mihail Zakharchenko ◽  
Кристина Мищенко ◽  
...  
Keyword(s):  
Carrying Capacity ◽  
Ball Bearing ◽  
Static Load ◽  
Ball Bearings ◽  
Load Carrying Capacity ◽  
Combined Load ◽  
Ball Rolling ◽  
Load Carrying ◽  
Bearing Rings ◽  
External Loads

The paper reports the consideration of the ball rolling-off mechanism of ball bearing rings. The regularities of the distribution of external combined load between balls are defined. There is offered a simulator of a rolling-ff process allowing the ratio definition between a load upon balls and acting factor including the angle of balls contact with a race and a correlation of a radial and axial external loads.

Limit Load Analysis of Cylindrical Vessels Under Internal Pressure and Axial Strain

2011 ◽  
Author(s):  
Xian-Kui Zhu
Keyword(s):  
Internal Pressure ◽  
Carrying Capacity ◽  
Pressure Vessel ◽  
Axial Strain ◽  
Limit State ◽  
Limit Load ◽  
Operating Pressure ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Load Analysis

Strain-based design is a newer technology used in safety design and integrity management of oil and gas pipelines. In a traditional stress-based design, the axial stress is relatively small compared to the hoop stress generated by internal pressure in a line pipe, and the limit state in the pipeline is usually load-controlled. In a strain-based design, however, axial strain can be large and the load-carrying capacity of pipelines could be reduced significantly below an allowed operating pressure, where the limit state is controlled by an axial strain. In this case, the limit load analysis is of great importance. The present paper confirms that the stress, strain and load-carrying capacity of a thin-walled cylindrical pressure vessel with an axial force are equivalent those of a long pressurized pipeline with an axial tensile strain. Elastic stresses and strains in a pressure vessel are then investigated, and the limit stress, limit strain and limit pressure are obtained in terms of the classical Tresca criterion, von Mises criteria, and a newly proposed average shear stress yield criterion. The results of limit load solutions are analyzed and validated using typical experimental data at plastic yield.

Design Parameter Reliability Analysis of Induction Bends

2014 ◽  
Author(s):  
Venkata M. K. Akula ◽  
Lance T. Hill
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Reliability Analysis ◽  
Carrying Capacity ◽  
Design Variable ◽  
Bending Moment ◽  
Load Carrying Capacity ◽  
Element Analysis ◽  
Design Variables ◽  
Load Carrying

Induction pipe bends are essential multi-functional components in offshore applications performing not only as fluid conductors but also as structural members providing flexibility to the entire pipeline. The deforming mechanism of bends minimizes the effects of pipe walking, length changes due to thermal expansion/contraction, etc. However, the extent to which the bend deforms to counteract the pipeline deformation, prior to reaching plastic collapse, is dictated by the design variables. The pipe bend design variables include the geometry of the bend, the inelastic material properties, and the operating loads. The study of the influence of these variables is central to improving upon existing bend designs and is the focus of this research. The certification process for bends typically involves ensuring the pipe bending moment is within limits set by agencies such as DNV, ASME, etc. Closed form solutions for the bending moment do exist but they often do not consider the effects of large deformation and the material nonlinearity of the bends. Since it is impractical to perform physical tests for every possible design, numerical techniques such as the finite element methods are an attractive alternative. Furthermore, for a given bend design, the design variables are prone to deviation, due to manufacturing process, operating conditions, etc., which introduces variation in the structural response and the resulting bending moment. In this paper, a nonlinear finite element analysis of induction bends is discussed followed by a presentation of a simulation workflow and reliability analysis. The finite element analysis utilizes a nonlinear Abaqus model with an user-subroutine prescribing precise end loading and boundary conditions. The workflow utilizes the design exploration software, Isight, which automates the solution process. Thereafter, reliability analysis is performed by varying the design variables, such as bend angle, ovalization, etc. and the results of the simulation are presented. The objective is to illustrate a solution technique for predicting the induction bend load carrying capacity and to examine design robustness. An automated workflow is demonstrated which allows for quick design variable changes, there by potentially reducing design time. The reliability analysis allows analysts to measure the variation in the load carrying capacity resulting from the deviation of design variable specifications. These demonstrations are intended to emphasize that to ensure the success of a bend design, it is important to not only predict the load carrying capacity accurately but also to perform reliability analysis for the design.

scholarly journals Finite Element Analysis on Reinforced Concrete Columns Strengthened by ECC Jacketing under Eccentric Compressive Load

2020 ◽  
Vol 24 (5) ◽  
pp. 77-91
Author(s):  
Mohammad Javad Memar ◽  
Ali Kheyroddin ◽  
Ali Hemmati
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Carrying Capacity ◽  
Tensile Strain ◽  
Bending Moment ◽  
Concrete Columns ◽  
Load Carrying Capacity ◽  
Normal Concrete ◽  
Eccentric Load ◽  
Load Carrying

Engineered cementitious composite (ECC) can be used for strengthening of concrete columns due to its similar structure and suitable connection to normal concrete and its special tension behavior. In this study, to analyse the columns, finite element (FE) method was used after verification by experimental results. Reference column was strengthened by normal concrete and ECC jacketing. The effects of type of jacket material, longitudinal reinforcement, compressive stress and ultimate tensile strain of ECC on variations of eccentric load-bending moment (P-M) interaction curves were investigated. Results showed that the use of ECC instead of normal concrete can increase load carrying capacity of strengthened column, due to tensile strain hardening behavior of this material. It was found that, amount of this increase depends on eccentricity of eccentric load and varying from 0.4-23%. In ECC jacketing, tensile cracks are continuous, but in concrete jacketing, there were discrete cracks and more quantity of damages. Due to higher load carrying capacity and better distribution of tensile cracks in ECC jacketing than normal concrete jacketing, the use of ECC is suitable for strengthening of reinforced concrete columns. Load carrying capacity of columns under concentric load and pure bending moment were calculated by theoretical method and the results were compared with FE.

Mechanical Properties of New Type Cold-Formed Steel Box-Shaped Component Welding Section Members

2013 ◽  
Vol 351-352 ◽  
pp. 601-609
Author(s):  
Sheng Wu
Keyword(s):  
Mechanical Properties ◽  
Carrying Capacity ◽  
Local Buckling ◽  
Bending Moment ◽  
Load Carrying Capacity ◽  
Unit Load ◽  
Compression Load ◽  
Section Modulus ◽  
Load Carrying ◽  
Cold Formed Steel

Cold-formed steel box-shaped section has the special features in both its mass center and moment center unification as double symmetry section and its outstanding advantage in moment and torsion rigidity. This paper presents a new kind of cold-formed steel box-shaped component welding sections, that is flanges opposite welding box-shaped component section DS. The mechanical properties such as buckling modes, load carrying capacity, rigidity, ductility and correlation curves of new section members which are subjected to axial compression, flexure, combined compression and bending have been analyzed by using nonlinear finite element method. The consumed steel quantities of per unit load carrying capacity between new section members and the same section dimensions of cold-formed C-section members have been compared systematically, too. Some conclusions can be drawn from above work that the DS section members have some superior properties, such as higher load carrying capacity and section modulus especially subjected to compression load, sufficient section stiffener and the sub-element local buckling hard to happen and so on. They are particularly suitable to withstand axial compressive loads, but also suitable to withstand the bending moment and bending loads. The consumed steel quantities are as almost 50% as the same dimension C-section members. The DS section members can go deep into the experimental study as to be used in the practical engineering.

EFFECTS OF CFRP REINFORCEMENTS ON THE BUCKLING BEHAVIOR OF THIN-WALLED STEEL CYLINDERS UNDER COMPRESSION

2012 ◽  
Vol 12 (01) ◽  
pp. 131-151 ◽  
Author(s):  
KRISHNA KUMAR BHETWAL ◽  
SEISHI YAMADA
Keyword(s):  
Carrying Capacity ◽  
Fiber Orientation ◽  
Buckling Analysis ◽  
Load Carrying Capacity ◽  
Buckling Strength ◽  
Frp Composite ◽  
Load Carrying ◽  
Thin Walled ◽  
Multiple Treatments ◽  
Collapse Behavior

This paper presents a novel way of strengthening thin-walled steel cylindrical shells against buckling during axial compression in which a small amount of fiber-reinforced polymer (FRP) composite, coated from both sides can increase the buckling strength effectively. The effects of the reinforcement and the angle of fiber orientation as well as initial geometric imperfections on the buckling load-carrying capacity have been made clear through the three kinds of analytical procedures; the conventional linear eigen value buckling analysis, the reduced stiffness (RS) buckling analysis and the fully nonlinear numerical experiments. These multiple treatments suggest obtaining valuable information for the design of FRP-based hybrid structural elements and discusses influence of FRP to increase the load-carrying capacity of the thin-walled metallic structures having complex buckling collapse behavior. This paper also discusses how the angle of fiber orientation affects on the buckling strength and the associated buckling modes of the thin-walled shells.

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