Effects of Geometric Imperfection on Bending Capacity of X80 Linepipe

2006 ◽  
Author(s):  
Nobuhisa Suzuki ◽  
Joe Kondo ◽  
Shigeru Endo ◽  
Nobuyuki Ishikawa ◽  
Mitsuhiro Okatsu ◽  
...  
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Finite Element Modeling ◽  
Bending Test ◽  
Moment Capacity ◽  
Geometric Imperfection ◽  
Bending Capacity ◽  
The Moment ◽  
Outside Diameter ◽  
Good Agreement

Validation of finite element modeling to predict bending capacity of linepipes and effects of geometric imperfection on the bending capacity are presented. A bending test of an X80 linepipe was conducted to discuss the validation and investigate the effects. The geometric imperfection of the linepipe about the outside diameter, the wall thickness and the longitudinal blister of the linepipe was measured in the round. Consequently, the results obtained by FEA taking into account the geometric imperfection present good agreement with the experimental data. And the moment capacity is virtually independent of the geometric imperfection however the strain capacity of the linepipe is quite susceptible to the geometric imperfection.

scholarly journals Development of a new test rig for the analysis of hydrodynamic bearings for rotors of microGT

2019 ◽  
Vol 113 ◽  
pp. 03002
Author(s):  
Carlo Alberto Niccolini Marmont Du Haut Champ ◽  
Fabrizio Stefani ◽  
Paolo Silvestri
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Gas Turbines ◽  
Dynamic Interaction ◽  
Journal Bearings ◽  
Radial Clearance ◽  
Test Rig ◽  
Small Clearance ◽  
Stiffness And Damping ◽  
Good Agreement

The aim of the present work is to design a test rig suited to investigate the dynamic interaction between rotor and hydrodynamic journal bearings in micro gas turbines (microGT), i.e. with reference to small bearings (diameter in the order of ten millimeters). Particularly, the device is capable of measuring the journal location. Therefore, the journal motion due to rotor vibrations can be displayed, in order to assess performance as well as stiffness and damping of the bearings. The new test rig is based on Bently Nevada Rotor Kit (RK), but substantial modifications are carried out. Indeed, the relative radial clearance of the original RK bearings is about 2/100, while it is in the order of 1/1000 in industrial bearings. Therefore, the same RK bearings are employed in the new test rig, but a new shaft has been designed in order to reduce the original clearance. The new shaft enables us to study the bearing behaviour for different clearances, as it is equipped with interchangeable journals. The experimental data yielded by the new test rig are compared with numerical results. These are obtained by means of a suitable finite element (FEM) code developed by our research group. It allows the Thermo Elasto-HydroDynamic (TEHD) analysis of the bearing in static and dynamic conditions. In the present paper, bearing static performances are analysed in order to assess the reliability of the journal location predictions by comparing numerical and experimental results. Such comparisons are presented for both large and small clearance bearings of original and modified RK, respectively. Good agreement is found only for the modified RK equipped with small clearance bearings (relative radial clearance equal to 8/1000). Nevertheless, rotor alignment is quite difficult with small clearance bearings and a completely new test rig is designed for future experiments.

Evaluation of Finite Element Calculations in a Cracked Cylinder Under Internal Pressure by Speckle Photography

1983 ◽  
Vol 50 (4a) ◽  
pp. 896-897 ◽  
Author(s):  
G. H. Kaufmann ◽  
A. M. Lopergolo ◽  
S. Idelsohn
Keyword(s):  
Experimental Data ◽  
Stress Intensity Factor ◽  
Finite Element ◽  
Stress Intensity ◽  
Mode I ◽  
Speckle Photography ◽  
Crack Line ◽  
Finite Element Calculations ◽  
Pressurized Cylinder ◽  
Good Agreement

The usefulness of using the speckle photography technique in fracture mechanics to check numerical calculations is demonstrated for an internally pressurized cylinder with a surface flaw. A pointwise technique was utilized to measure the opening displacements along the crack line and the Mode I stress-intensity factor was determined by extrapolating these results to the crack tip. Finite element calculations were performed to be compared with experimental data and good agreement was obtained.

Analysis on the Moment-Curvature Relationship for Prestressed UHPFRC Beams without Stirrup

2011 ◽  
Vol 255-260 ◽  
pp. 236-240
Author(s):  
Sang Mook Han ◽  
Qing Yong Guo
Keyword(s):  
Experimental Data ◽  
Tensile Strength ◽  
Steel Fibre ◽  
Fibre Reinforcement ◽  
Cracking Behavior ◽  
Perfectly Plastic ◽  
History Of ◽  
Elastic Perfectly Plastic ◽  
The Moment ◽  
Good Agreement

To simplify the analysis, an elastic perfectly plastic stress-strain law was presented for UHPFRC. The post-cracking behavior was described by the average constant post-crack tensile strength. A strain parameter μ is proposed to evaluate the performance and efficiency of steel fibre reinforcement. 8 rectangular beams were tested in this investigation. Based on the proposed constitutive model, the full history of their flexural moment-curvature relationship for UHPFRC beams was calculated and compared with experimental data on prestressed UHPFRC beams. Good agreement between calculated strengths and experimental data was obtained.

Failure of Thin-Walled Pipes With D/T up to 140 and Conclusions for the Design Codes

2016 ◽  
Author(s):  
Henry Schau ◽  
Lilit Mkrtchyan ◽  
Michael Johannes
Keyword(s):  
Yield Stress ◽  
Bending Moment ◽  
Bending Stress ◽  
Dynamic Analyses ◽  
Asme Code ◽  
Stress Intensification Factor ◽  
Thin Walled ◽  
The Moment ◽  
Outside Diameter ◽  
Good Agreement

The influence of imperfections on the instability bending moment of thin-walled straight pipes with D/t-ratios (D - outside diameter, t - wall thickness) up to 140 is determined using nonlinear Finite Element (FE) analyses. The analyses show that the type and size of the imperfection, the D/t ratio and the material properties have significant influences on the instability moment. The nominal bending stress of pipes (yield stress 500 MPa) with D/t > 70 and an ovality of 0.5% is smaller than the yield stress at the instability point. That means, the failure occurs by buckling in the elastic range of the nominal bending stress. In static analyses the moment decreases abruptly after reaching the instability moment. In the dynamic analyses the pipe jumps abruptly to the state with smaller moment. The obtained results are applied to calculate the B2 index for pipes with D/t ≤ 140. The B2 indices for thin-walled straight pipes with D/t > 40 are considerably higher than 1.0. In general, there is a good agreement between the calculated B2 values and the values of the ASME Code. A correction factor for higher temperatures is not necessary. The allowable moments calculated with the B2 index and the stress intensification factor i are compared. The bending moments from disabled thermal expansion and anchor movements have the same effect on the failure due to (plastic) buckling as the primary moments and must be taken into account.

A reaction-force-validated soccer ball finite element model

2016 ◽  
Vol 231 (1) ◽  
pp. 43-49 ◽  
Author(s):  
Zahari Taha ◽  
Mohd Hasnun Arif Hassan
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Finite Element Model ◽  
Reaction Force ◽  
Element Model ◽  
Optimal Number ◽  
Ball Impact ◽  
Soccer Ball ◽  
Mesh Density ◽  
Good Agreement

The soccer ball is one of the important pieces of equipment in the game of soccer. It undergoes various forms of impact during the game. In order to numerically investigate the occasions of ball impact such as soccer heading, a validated finite element model of a soccer ball is required. Therefore, a model was developed incorporating material properties obtained from literature. To ensure the accuracy of the model, it was validated against an established soccer ball model and experimental data of the coefficient of restitution, contact time, longitudinal deformation and reaction force. In addition, a parametric study of the mesh density was also performed to determine the optimal number of elements. The developed soccer ball model was found to be in a good agreement with the literature and experimental data. This suggests that, the soccer ball model is capable of replicating the impacts of interest. This article details the development of the model and the validation processes.

Bending Capacity Analyses of Corroded Pipeline

2011 ◽  
Vol 134 (2) ◽  
Author(s):  
Weiwei Yu ◽  
Pedro M. Vargas ◽  
Dale G. Karr
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Carrying Capacity ◽  
Nonlinear Finite Element ◽  
Secondary Effects ◽  
Element Analysis ◽  
Moment Capacity ◽  
Bend Testing ◽  
Bending Capacity ◽  
Point Bend

Appendix G of the ASME B31 pipeline and piping codes addresses the pressure containment capacity of pipelines and vessels with locally corroded sections. However, the ability of corroded sections to carry moment, for example, in thermal loops, is not addressed in fitness-for-service codes today. This paper presents nonlinear Finite Element Analysis (FEA) and full-scale 4-point-bend testing of pipes with locally-thinned-areas (LTAs) to simulate corrosion. The LTAs are loaded in compression, and the buckle moment is used as the carrying capacity of the corroded section. The nonlinear FEA is found to match the experimental results, validating this methodology for computing moment capacity in corroded sections. Significant secondary effects were found to affect the testing results. This paper identifies and quantifies these effects. Also, somewhat contrary to intuition, internal pressure is demonstrated to adversely affect the bending capacity for the intermediate-low D/t ratio (17.25) pipe tested.

scholarly journals Moment redistribution in continuous prestressed concrete box girder with corrugated steel webs

2019 ◽  
Author(s):  
Jin-Sheng Du ◽  
Pui-Lam Ng ◽  
Xiang Ma ◽  
Jian Wang
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Prestressed Concrete ◽  
Concrete Strength ◽  
Bending Moment ◽  
Element Model ◽  
Box Girder ◽  
Moment Redistribution ◽  
Calculation Results ◽  
The Moment

A fibre-finite-element model of continuous prestressed concrete (PC) composite box girder with corrugated steel webs is established with force-based elements using OpenSees. After the model is validated with existing experimental data, the effects of reinforcement index in upper and lower flanges, effective prestress and concrete strength on the moment redistribution behaviour is analysed. It is shown that increasing the reinforcement index in lower flange or effective prestress can increase the amount of bending moment redistribution, whereas increasing the concrete strength or reinforcement index in upper flange can decrease the amount of bending moment redistribution. By inspecting the sensitivity of parameters, it is found that the reinforcement index in lower flange has the most significant influence on the moment redistribution, followed by the concrete strength and then by the effective prestress, while the reinforcement index in upper flange has only little impact on the moment redistribution. The calculation results are compared with the existing formulas. Finally, a moment redistribution formula is proposed for continuous PC box girder with corrugated steel webs.

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