Local Buckling Behavior of 48″, X80 High-Strain Line Pipes

2010 ◽  
Author(s):  
Nobuhisa Suzuki ◽  
Hisakazu Tajika ◽  
Satoshi Igi ◽  
Mitsuru Okatsu ◽  
Joe Kondo ◽  
...  
Keyword(s):  
High Strain ◽  
Compressive Strain ◽  
Local Buckling ◽  
Bending Test ◽  
Test Results ◽  
Geometric Properties ◽  
Pipe Surface ◽  
Bending Tests ◽  
Buckling Behavior ◽  
Post Buckling

Two bending tests of X80-grade, 48″ high-strain line pipes pressurized to 60% SMYS were conducted to investigate local buckling behavior. The thickness and D/t ratio of the line pipes were 22.0 mm and 55.4, respectively. The mean Y/T ratio of the high-strain pipes was 0.82. A full-scale bending test apparatus was constructed to conduct the bending tests. The bending test results clarified that the pipes have the 2D average critical compressive strain of 1.51 and 1.67%, which satisfy the strain demand of 1.35%. Validation of FEA is conducted taking into account geometric properties of the pipes in terms of outside diameter and thickness and longitudinal flatness. The FEA results coincide with the test results with respect to peak load, critical displacement, critical rotation and critical compressive strain. The FEA results about the load and displacement relationship also show good agreement with the test results during post-buckling deformation. One developed wrinkle and some small wrinkles were observed on the pipe surface during post-buckling deformation, whose cross sections were fairly captured considering the geometric properties.

The Initial Post-buckling Behavior of Face-Sheet Delaminations in Sandwich Composites

2003 ◽  
Vol 70 (2) ◽  
pp. 191-199 ◽  
Author(s):  
G. A. Kardomateas ◽  
H. Huang
Keyword(s):  
Interface Crack ◽  
Transverse Shear ◽  
Compressive Strain ◽  
Sandwich Beam ◽  
Local Buckling ◽  
Face Sheet ◽  
Material System ◽  
Buckling Behavior ◽  
Post Buckling ◽  
Composite Face

Should an interface crack between the layers of the composite face-sheet or between the core and the composite face-sheet of a sandwich beam/plate exists, local buckling and possible subsequent growth of this interface crack (delamination) may occur under compression. In this study, the buckling, and initial post-buckling behavior is studied through a perturbation procedure that is based on the nonlinear beam equations with transverse shear included. Closed-form solutions for the load and midpoint delamination deflection versus applied compressive strain during the initial postbuckling phase are derived. Illustrative results are presented for several sandwich construction configurations, in particular with regard to the effect of material system and transverse shear.

Compressive and Tensile Strain Capacities of 48” X80 Line Pipes

2012 ◽  
Author(s):  
Hisakazu Tajika ◽  
Satoshi Igi ◽  
Takahiro Sakimoto ◽  
Shigeru Endo ◽  
Seishi Tsuyama ◽  
...  
Keyword(s):  
Tensile Strain ◽  
High Strain ◽  
Uniform Elongation ◽  
Compressive Strain ◽  
Experimental Studies ◽  
Local Buckling ◽  
Base Material ◽  
Pipe Surface ◽  
Strain Capacity ◽  
Strain Limit

This paper presents the results of experimental studies focused on the strain capacity of X80 linepipe. A full-scale bending tests of X80 grade, 48″ high-strain linepipes pressurized to 60% SMYS were conducted to investigate the compressive strain limit and tensile strain limit. The tensile properties Y/T ratios and uniform elongation of the pipes had variety. Three of four pipes are high strain pipes and these Y/T ratios are intentionally low with manufacturing method. One of these high-strain pipe was girth welded in its longitudinal center to investigate the effect of girth weld to strain capacity. The other was set as a conventional pipe that have higher Y/T ratio to make comparative study. The compressive strain limit focused on the critical strain at the formation of local buckling on the compression side of bending. After pipe reaches its endurable maximum moment, one large developed wrinkle and some small wrinkles on the pipe surface during bending deformation were captured relatively well from observation and strain distribution measurement. The tensile strain limit is discussed from the viewpoint of competition of two fracture phenomena: ductile crack initiation/propagation from an artificial notch at the HAZ of the girth weld, and strain concentration and rupture in the base material at the tension (opposite) side of the local buckling position.

Girth Weld Strength Matching Effect on Tensile Strain Capacity of Grade X70 High Strain Line Pipe

2018 ◽  
Author(s):  
Hisakazu Tajika ◽  
Takahiro Sakimoto ◽  
Tsunehisa Handa ◽  
Rinsei Ikeda ◽  
Joe Kondo
Keyword(s):  
High Strain ◽  
Limit State ◽  
Full Scale ◽  
Bending Test ◽  
High Grade ◽  
Line Pipe ◽  
Bending Tests ◽  
Strain Capacity ◽  
Pipeline Project ◽  
Pipe Bending

Recently high grade pipeline project have been planned in hostile environment like landslide in mountain area, liquefaction in reclaimed land or the frost heave in Polar Regions. Geohazards bring large scale ground deformation and effect on the varied pipeline to cause large deformation. Therefore, strain capacity is important for the pipeline and strain based design is also needed to keep gas transportation project in safe. High grade steel pipe for linepipe tends to have higher yield to tensile (Y/T) ratio and it has been investigated that the lower Y/T ratio of the material improves strain capacity in buckling and tensile limit state. In onshore pipeline project, pipe usually transported in 12 or 18m each and jointed in the field. Girth weld (GW) is indispensable so strength matching of girth weld towards pipe body is important. In this study strain capacity of Grade X70 high strain pipes with size of 36″ OD and 23mm WT was investigated with two types of experiments, which are full scale pipe bending tests and curved wide plate tests. The length of the specimen of full scale bending tests were approximately 8m and girth weld was made in the middle of joint length. A fixed internal pressure was applied during the bending test. Actual pipe situation in work was simulated and both circumferential and longitudinal stress occurred in this test. Test pipes were cut and welded, GTAW in first two layer and then finished by GMAW. In one pipe, YS-TS over-matching girth weld (OVM) joint was prepared considering the pipe body grade. For the other pipe, intentionally under-matching girth weld (UDM) joint was prepared. After the girth welding, elliptical EDM notch were installed in the GW HAZ as simulated weld defect. In both pipe bending tests, the buckling occurred in the pipe body at approximately 300mm apart from the GW and after that, deformation concentrated to buckling wrinkle. Test pipe breaking locations were different in the two tests. In OVM, tensile rupture occurred in pipe body on the backside of buckling wrinkle. In UDM, tensile rupture occurred from notch in the HAZ. In CWP test, breaking location was the HAZ notch. There were significant differences in CTOD growth in HAZ notch in these tests.

Aspects of Testing and Material Properties of Fiber Concrete

2019 ◽  
Vol 292 ◽  
pp. 9-14 ◽  
Author(s):  
Oldrich Sucharda ◽  
Vlastimil Bilek
Keyword(s):  
Tensile Strength ◽  
Material Properties ◽  
Bending Test ◽  
Test Results ◽  
Functional Dependencies ◽  
Split Tensile Strength ◽  
Bending Tests ◽  
Fibre Concrete ◽  
Fiber Concrete ◽  
Concrete Mixer

Concrete is typical composite material and its properties can be very variable. Material properties are also influenced with the technology of processing, manufacturing and treatment after concreting. Reinforcement in form of fibers is often added for improving tensile strength. This paper deals with specific testing of fibre concrete. Test results of series of specimens are presented for selected transport concrete composition, which is reinforced with amount of fibers 25, 50, 75 kg / m3. Fibers were added directly into the into the concrete mixer in the factory. Each series includes more than 25 test samples. The tests include the compressive strength of a cube and cylindrical, testing of modulus of elasticity, and the split tensile strength in the direction perpendicular to and parallel to the filling. Within the research project also a few types of bending tests were performed. Four variants of bending test that vary in span of 500 or 600 mm, samples with and without a notch, and in a three- / four-point configuration. As a summary, broader evaluation and functional dependencies are derived.

scholarly journals Cyclic fatigue behaviour of hydrothermally aged 3Y-TZP ceramics in 4-point bending tests

2021 ◽  
Vol 15 (2) ◽  
pp. 184-194
Author(s):  
Renato Souza ◽  
Roberto Duarte ◽  
Manuel Alves ◽  
Juliana Daguano ◽  
Santos dos ◽  
...  
Keyword(s):  
Bending Strength ◽  
Ceramic Materials ◽  
Cyclic Fatigue ◽  
Fatigue Behaviour ◽  
Fatigue Tests ◽  
Bending Test ◽  
Test Results ◽  
Transformation Toughening ◽  
Bending Tests ◽  
M Phase

Fatigue is one of the most important properties to be considered in ceramic dental implants due to cyclic mechanical stresses arising from the chewing process. In this work, the fatigue behaviour of hydrothermally degraded ZrO2-based ceramics stabilized with 3mol% Y2O3 (3Y-TZP) was studied in 4-point bending tests. Samples of 3Y-TZP were compacted (100MPa), sintered at 1475 ?C for 2 h, polished and hydrothermally degraded in an autoclave as described in the ISO-13356 standard. The samples were characterized by their relative density, crystalline phase composition, microstructure and surface roughness. The highly dense (>99.6%TD) sintered 3Y-TZP ceramics has only tetragonal t-ZrO2 phase, even after hydrothermal ageing. Furthermore, the ceramic materials presented a Vickers hardness of 12.7?0.2GPa, a fracture toughness of 7.1?0.3MPa?m1/2 and a 4-point bending strength of 940.1?67MPa. Based on the bending test results 5 different stress levels for the fatigue tests were selected and conducted by cyclic 4-point bending obtaining the S-N curve. Weibull statistics was used for the statistical analysis. The fatigue tests indicate that the limit of fatigue resistance of this 3Y-TZP ceramics is around 550MPa, i.e. higher than the limits established in the ISO-13356 standard for the use of Y-TZP ceramics for the manufacture of implants. The fatigue behaviour of the investigated 3Y-TZP ceramics was related to the toughening mechanisms acting in Y-TZP ceramics, such as transformation toughening related to t?m phase transformation and microcracking.

Pure Bending Test on a Box Girder With Low Panel’s Slenderness

2018 ◽  
Author(s):  
José Manuel Gordo ◽  
Carlos Guedes Soares
Keyword(s):  
Residual Stresses ◽  
Progressive Collapse ◽  
Bending Moment ◽  
Bending Test ◽  
Box Girder ◽  
Buckling Behavior ◽  
Linear Characteristic ◽  
Collapse Mode ◽  
Post Buckling ◽  
The Moment

The results of a four points bending test on a box girder are presented. The experiment is part of series of tests with similar configuration but different thickness, spacing between longitudinal stiffeners and span between frames. The present work refers to the stockiest plate box girder with a plate’s thickness of 4 mm and a span between frames of 800 mm. The experiment includes initial loading cycles allowing for residual stresses relief. It also includes a series of cycles close to collapse load allowing the analysis of linear characteristic at high levels of load. The moment curvature relationship is established for a large range of curvatures. The ultimate bending moment of the box is evaluated and compared with the first yield moment and the plastic moment allowing the evaluation of the efficiency of the structure. The post buckling behavior and collapse mode are characterized. Comparison of the experiment with a progressive collapse method is made taking into consideration the effect of residual stresses on envelop of the moment curvature curve of the structure.

Buckling and Tensile Strain Capacity of Girth Welded 48″ X80 Pipeline

2013 ◽  
Author(s):  
Satoshi Igi ◽  
Mitsuru Ohata ◽  
Takahiro Sakimoto ◽  
Junji Shimamura ◽  
Kenji Oi
Keyword(s):  
Crack Growth ◽  
Tensile Strain ◽  
Compressive Strain ◽  
Bending Test ◽  
Ductile Crack ◽  
Pipe Surface ◽  
Strain Capacity ◽  
Ductile Crack Growth ◽  
Strain Limit ◽  
Tensile Strain Capacity

This paper presents the experimental and analytical results focused on the compressive and tensile strain capacity of X80 linepipe. A full-scale bending test of girth welded 48″ OD X80 linepipes was conducted to investigate the compressive strain limit regarding to the local buckling and tensile strain limit regarding to the girth weld fracture. As for the compressive buckling behavior, one large developing wrinkle and some small wrinkles on the pipe surface were captured relatively well from observation and strain distribution measurement after pipe reaches its endurable maximum bending moment. The tensile strain limit is discussed from the viewpoint of competition of two fracture phenomena: ductile crack initiation / propagation from an artificial notch at the HAZ of the girth weld, and strain concentration and necking / rupture in the base material. The ductile crack growth behavior from the girth weld notch is simulated by FE-analysis based on the proposed damage model, and compared with the experimental results. In this report, it is also demonstrated that the simulation model can be applicable to predicting ductile crack growth behaviors from a circumferentially notched girth welded pipe with internal high pressure subjected to post-buckling loading.

Investigations on the Local Buckling Response of High Strength Linepipe

2008 ◽  
Author(s):  
Ali Fatemi ◽  
Shawn Kenny ◽  
Millan Sen ◽  
Joe Zhou ◽  
Farid Taheri ◽  
...  
Keyword(s):  
Large Scale ◽  
Local Buckling ◽  
High Strength ◽  
Order Effects ◽  
Geometric Imperfections ◽  
Mesh Topology ◽  
Buckling Behavior ◽  
Post Buckling ◽  
Element Simulator ◽  
Experimental Response

A numerical modeling procedure was developed, using the finite-element simulator ABAQUS/Standard, to predict the local buckling and post-buckling response of high strength pipelines subject to combined state of loading. The numerical procedures were calibrated using test data from large-scale experiments examining the local buckling of high strength linepipe. The numerical model’s response was consistent with the measured experimental response for predicting the local buckling behavior well into the post-yield range. A parametric study was conducted that examined element selection, mesh topology, second-order effects, geometric imperfections and material properties. The results from this study are presented.

scholarly journals PENIPISAN PIPA KETEL AKIBAT ELEMEN KOROSIF AIR

2016 ◽  
Vol 16 (1) ◽  
Author(s):  
M. N. Setia Nusa ◽  
Hernadi .
Keyword(s):  
Tensile Test ◽  
Structure Analysis ◽  
Pitting Corrosion ◽  
Hardness Test ◽  
Bending Test ◽  
Test Results ◽  
Analysis Method ◽  
Micro Structure ◽  
Bending Tests ◽  
Normal Standard

Inspection and testing is done to determine the metallurgical phenomena that occur on the boiler pipes that have been operating several years continuously at a temperature of 560 ° C. The study is also intended to determine the operational feasibility of the pipeline and to avoid undetected damage.Investigation of these pipes is also carried out in the laboratory with micro-structure analysis method, inspection crust, tensile test, bending test, hardness and thickness test.From the analysis of the microstructure, boiler pipes are in condition ferrite pearlite spheroidization with a crust that is thick and contains graphite. In addition, The pipes are attacked by uniform and pitting corrosion. The results of tensile and bending tests are still normal (standard). The hardness test results show significant values compared to the standard, as well as the thickness of the pipe thinning as a result of the corrosion process.AbstrakInspeksi dan pengujian dilakukan untuk mengetahui fenomena metalurgis yang terjadi terhadap pipa ketel uap yang sudah beroperasi beberapa tahun secara terus menerus pada suhu 560°C. Penelitian juga dimaksudkan untuk mengetahui kelayakan operasional pipa tersebut dan untuk menghindari terjadinya kerusakan yang tidak terdeteksiInvestigasi pipa-pipa tersebut juga dilakukan di laboratorium dengan metode analisa struktur mikro, pemeriksaan kerak, uji tarik, uji bending, uji kekerasan dan ketebalan.Dari analisa struktur mikro, pipa ketel berada pada kondisi ferrit spheroidisasi perlit dengan lapisan kerak yang cukup tebal serta mengandung grafit. Selain itu juga terjadi serangan korosi merata dan korosi sumuran. Hasil uji tarik dan hasil uji bengkok masih normal (memenuhi standar). Hasil uji kekerasan terjadi penurunan nilai yang signifikan dibanding standar, demikian juga pada ketebalan pipa terjadi penipisan akibat dari adanya proses korosi.Keywords: Boiler pipe, spheroidization, corrosion, thinning.

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