Diagnosis of the load-carrying capacity of pipes containing a longitudinal crack when loaded by an axial force and internal pressure

1994 ◽  
Vol 26 (12) ◽  
pp. 872-878
Author(s):  
V. N. Bastun
Keyword(s):  
Internal Pressure ◽  
Axial Force ◽  
Carrying Capacity ◽  
Longitudinal Crack ◽  
Load Carrying Capacity ◽  
Load Carrying

Investigation on the Post-Ultimate Strength Behaviour of Damaged Stiffened Plate of Ship Structure

2016 ◽  
Author(s):  
Weijun Xu ◽  
Minjie Yuan ◽  
Xiaotian Wang
Keyword(s):  
Ultimate Strength ◽  
Carrying Capacity ◽  
Crack Depth ◽  
Plate Thickness ◽  
Longitudinal Crack ◽  
Load Carrying Capacity ◽  
Stiffened Plate ◽  
Ship Structure ◽  
Plate Length ◽  
Load Carrying

Post-ultimate strength behaviour of ship structure can directly reflect its changing tendency of load carrying capacity. When the external load exerted on the ship structure exceeds the ultimate strength, sharply reduction of load carrying capacity will occur, especially for the damaged ship structure induced from grounding or collision. This paper focuses on the investigation on the post-ultimate strength behaviour of damaged stiffened plate of ship structure by using FEM, a series of stiffened plate modeling with different kinds of cracks are constructed. The parameters of crack includes length, width, depth, plate thickness and distribution direction. The post-ultimate strength behaviour of stiffened plate with cracks and intact ones are compared. Conclusion can be drawn as follows: (1) crack can induce the reduction of ultimate strength of stiffened plate, meanwhile, the stiffness and its load carrying capacity decrease accordingly. (2) in terms of stiffened thin plate, length of crack has a significant influence on the post-ultimate strength behaviour, the width of the crack has a huge influence on ultimate strength while the depth of crack has little influence; in terms of stiffened thick plate, the influence of crack depth on the post-ultimate strength behaviour becomes obvious. The width of the crack influence the post-ultimate strength behaviour a lot. (3) compare to the transverse crack, the influence of longitudinal crack on the post-ultimate strength behaviour is not obvious.

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.

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.

Ultimate Load-Carrying Capacity of Pipe-Plate Vierendeel Truss Joints

2013 ◽  
Vol 838-841 ◽  
pp. 503-509
Author(s):  
Jie Luo ◽  
Jian Chun Xiao ◽  
Zhe Lu ◽  
Xiao Xiao Wei ◽  
Hong Xi Li ◽  
...  
Keyword(s):  
Axial Force ◽  
Carrying Capacity ◽  
Failure Modes ◽  
Ultimate Load ◽  
Plate Thickness ◽  
Load Carrying Capacity ◽  
Plate Height ◽  
Joint Failure ◽  
Load Carrying ◽  
Ultimate Load Carrying Capacity

To study the ultimate load-carrying capacity of pipe-plate Vierendeel truss joints, the analyses of joint failure modes and parameter effects were undertaken using nonlinear finite element method and uniform design approach. The plate instability was included in the failure modes. Factors such as the pipe diameter, the pipe thickness, the plate width, the plate height, and the plate thickness were considered in the joint models. Three kind of loading conditions on the plate, the axial force, the moment, the composed loading of axial force and moment were analyzed. The relationships between the joint failure modes and the factors are achieved. The joint ultimate load-bearing capacity formulas are proposed by regression analysis. The effects of factors on the joint strength are illustrated.

scholarly journals External Strengthening of Corrosion-Defected Beam–Column Members Using a CFRP Sheet

Fibers ◽  
2019 ◽  
Vol 7 (6) ◽  
pp. 53
Author(s):  
Nameer A. Alwash ◽  
Mohammed M. Kadhum ◽  
Ahmed M. Mahdi
Keyword(s):  
Axial Force ◽  
Carrying Capacity ◽  
Reinforced Concrete Beam ◽  
Transverse Load ◽  
Load Carrying Capacity ◽  
Significant Deterioration ◽  
Axial Forces ◽  
Load Carrying ◽  
External Strengthening ◽  
Cfrp Sheet

The efficiency of external strengthening using CFRP (Carbon Fiber Reinforced Polymer) sheets to rehabilitate corrosion-defected RC (Reinforced Concrete) beam–column members is experimentally studied. ALL specimens were tested under a combined axial force and transverse load until failure. The axial forces were applied with two levels either 25% or 50% of the ultimate design load of control specimen. The accelerated corrosion process was used to get steel reinforcement corrosion inside the concrete at three levels, 0% and approximately 5% and 20%, according to Faraday’s law. External strengthening with a CFRP sheet was used in this study to overcome the effect of deterioration in the mechanical properties of the corroded steel bars. A significant deterioration in the load carrying capacity, stiffness, and serviceability was recorded for corrosion-defected specimens. The increase of the axial force was recorded as a positive effect on the ultimate strength, stiffness, and serviceability of the testing specimens. This effect was clearly evident for the defected specimens, with an increasing corrosion level, by decreasing the adverse effects of corrosion. The external strengthening with a CFRP sheet restored the load-carrying capacity, stiffness, and serviceability to an undamaged state.

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.

Load Carrying Capacity of Steel Arch Reinforcement Taking into Account the Geometrical and Physical Nonlinearity

2016 ◽  
Vol 821 ◽  
pp. 709-716 ◽  
Author(s):  
Petr Janas ◽  
Lenka Koubova ◽  
Martin Krejsa
Keyword(s):  
Numerical Model ◽  
Axial Force ◽  
Carrying Capacity ◽  
Stress Test ◽  
Bending Moment ◽  
Physical Nonlinearity ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Geometrical And Physical Nonlinearity ◽  
Strain Stress

The paper deals with the calculation of the load carrying capacity of the steel arch reinforcements of underground and mine works with respect to the resulting large displacement and physical nonlinearities. Solution is based on the application of the so-called effective bending stiffness, which is defined as a function of the axial force and bending moment. The numerical model was verified using the values of the load carrying capacity, which have been experimentally obtained using strain-stress test, and implemented into the software that allows very effectively calculate load carrying capacity of steel arch reinforcements.

Limit-Load Analysis of Pipe Bends Under Out-of-Plane Moment Loading and Internal Pressure

2001 ◽  
Vol 124 (1) ◽  
pp. 32-37 ◽  
Author(s):  
Hashem M. Mourad ◽  
Maher Y. A. Younan
Keyword(s):  
Internal Pressure ◽  
Carrying Capacity ◽  
Limit Load ◽  
Factor H ◽  
Load Carrying Capacity ◽  
Pipe Bend ◽  
Loading Mode ◽  
Load Carrying ◽  
Out Of Plane ◽  
Plane Direction

The purpose of this work is to study the load-carrying capacity of pipe bends, with different pipe bend factor h values, under out-of-plane moment loading; and to investigate the effect of internal pressure on the limit moments in this loading mode. The finite element method is used to model and analyze a standalone, long-radius pipe bend with a 16-in. nominal diameter, and a 24-in. bend radius. A parametric study is performed in which the bend factor takes ten different values between 0.0632 and 0.4417. Internal pressure is incremented by 100 psi for each model, until the limit pressure of the model is reached. The limit moments were found to increase when the internal pressure is incremented. However, beyond a certain value of pressure, the effect of pressure is reversed due to the additional stresses it engenders. Expectedly, increasing the bend factor leads to an increase in the value of the limit loads. The results are compared to those, available in the literature, of a similar analysis that treats the in-plane loading mode. Pipe bends are found to have the lowest load-carrying capacity when loaded in their own plane, in the closing direction. They can sustain slightly higher loads when loaded in the out-of-plane direction, and considerably higher loads under in-plane bending in the opening direction.

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