Allowable Limit and Finite Element Analysis of Pipes With Local Wall Thinning Subjected to Bending Moment

2004 ◽  
Author(s):  
Seok Hwan Ahn ◽  
Ki Woo Nam ◽  
Koji Takahashi ◽  
Kotoji Ando
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Failure Modes ◽  
Bending Test ◽  
Element Analysis ◽  
Allowable Limit ◽  
Pipe Surface ◽  
Wall Thinning ◽  
Plastic Analysis ◽  
Local Wall Thinning

Fracture behaviors of pipes with local wall thinning are very important for the integrity of power plant piping system. In this study, monotonic bending tests without internal pressure are conducted on 1.91-inch diameter Schedule 80 STS370 full-scale carbon steel pipe specimens. Fracture strengths of locally wall thinned pipes were calculated by elasto-plastic analysis using finite element method. The elasto-plastic analysis was performed by FE code ANSYS. We simulated various types of local wall thinning that can be occurred at pipe surface due to coolant flow. Locally wall thinned shapes were machined to be different in size along the circumferential or axial direction of straight pipes. We investigated fracture strengths and failure modes of locally wall thinned pipes by four-point bending test. From the test results, failure modes could be divided three types, ovalization, local buckling and crack initiation. And, the allowable limit of pipes with local wall thinning was investigated. In addition, we compared the simulated results by finite element analysis with experimental data. The failure mode, fracture strength and fracture behavior obtained from the tests showed well agreement with analytic results.

3428 Finite element analysis of failure behavior of elbow pipe with local wall thinning

2006 ◽  
Vol 2006.1 (0) ◽  
pp. 567-568
Author(s):  
Tomohiro UENO ◽  
Koji TAKAHASHI ◽  
Kotoji ANDO ◽  
Akitaka HIDAKA ◽  
Masakazu HISATSUNE ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Failure Behavior ◽  
Element Analysis ◽  
Wall Thinning ◽  
Local Wall Thinning

Finite Element Analysis on the Failure Behavior of Straight Pipe With Wall Thinning

2004 ◽  
Author(s):  
Ken Inoue ◽  
Koji Takahashi ◽  
Kotoji Ando ◽  
Seok Hwan Ahn ◽  
Ki Woo Nam ◽  
...  
Keyword(s):  
Finite Element ◽  
Failure Modes ◽  
Local Buckling ◽  
Metal Loss ◽  
Failure Behavior ◽  
Straight Pipe ◽  
Element Analysis ◽  
Deformation And Failure ◽  
Wall Thinning ◽  
Local Wall Thinning

Monotonic four-point bending tests were conducted using straight pipe specimens 102 mm in diameter with local wall thinning in order to investigate the effects of the depth, shape, and location of wall thinning on the deformation and failure behavior of pipes. The local wall thinning simulated erosion/corrosion metal loss. The deformation and fracture behavior of the straight pipes with local wall thinning was compared with that of non wall-thinning pipes. The failure modes were classified as local buckling, ovalization, or crack initiation depending on the depth, shape, and location of the local wall thinning. Three-dimensional elasto-plastic analyses were carried out using the finite element method. The deformation and failure behavior, simulated by finite element analyses, coincided with the experimental results.

Finite element analysis on fracture behavior of pipe with local wall thinning

2004 ◽  
Vol 2004 (0) ◽  
pp. 81-82
Author(s):  
Kazuomi KAWATO ◽  
Masato ONO ◽  
Koji TAKAHASHI ◽  
Kotoji ANDO ◽  
Ki-Woo Nam
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Fracture Behavior ◽  
Element Analysis ◽  
Wall Thinning ◽  
Local Wall Thinning

Use of built-up H sections as secondary members in topside modules

2018 ◽  
Vol 233 (3) ◽  
pp. 825-843
Author(s):  
Jeong Du Kim ◽  
Beom-Seon Jang ◽  
Sang Woong Han ◽  
Sang Hoon Shim ◽  
Sung Woo Im
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Failure Modes ◽  
Nonlinear Finite Element Analysis ◽  
Nonlinear Finite Element ◽  
Bending Test ◽  
Limit States ◽  
Element Analysis ◽  
Four Point Bending ◽  
Offshore Industry

There have been many attempts to widely utilize built-up H sections to secure flexibility in structural design. Much research into the structural strengths and limit states of built-up H sections, therefore, has been carried out. However, a practical redesign methodology taking advantage of built-up H beams has yet to be introduced into the offshore industry. In this study, a comprehensive investigation into built-up H sections is carried out, based on which, a new redesign procedure for weight reduction herein is suggested. First of all, on the basis of the ANSI/AISC 360-10, the differences between the rolled H and built-up H sections are investigated in terms of their various strengths. Then, a secondary-member redesign procedure is established as a means of reducing structural weight by replacing rolled H sections with built-up H sections. In that procedure, the built-up H section cross-section is modified according to the failure modes of reference rolled H sections. The redesign procedure is verified by a nonlinear finite element analysis and four-point bending test. Through the nonlinear finite element analysis and experiment on the reference rolled H section and built-up H section obtained by the redesign procedure, it is observed that the weight of the built-up H section is reduced by about 15% while a flexural strength similar to that of the reference rolled H section is maintained. The suggested redesign procedure is then applied to three floating production storage offloading (FPSO) topside modules for demonstration purposes. In the results, the total structural weights of the reference topside modules are reduced by approximately 3%–5% by employing built-up H sections in secondary members in lieu of rolled H sections. The results indicate that, in many cases, built-up H sections can be used as secondary members to reduce the structural weight of topside modules.

TTK Chitra tilting disc heart valve model TC2: An assessment of fatigue life and durability

2017 ◽  
Vol 231 (8) ◽  
pp. 758-765 ◽  
Author(s):  
NN Subhash ◽  
Adathala Rajeev ◽  
Sreedharan Sujesh ◽  
CV Muraleedharan
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Fatigue Life ◽  
Heart Valve ◽  
Life Prediction ◽  
Heart Valves ◽  
Failure Modes ◽  
Fatigue Life Prediction ◽  
Element Analysis ◽  
Valve Model

Average age group of heart valve replacement in India and most of the Third World countries is below 30 years. Hence, the valve for such patients need to be designed to have a service life of 50 years or more which corresponds to 2000 million cycles of operation. The purpose of this study was to assess the structural performance of the TTK Chitra tilting disc heart valve model TC2 and thereby address its durability. The TC2 model tilting disc heart valves were assessed to evaluate the risks connected with potential structural failure modes. To be more specific, the studies covered the finite element analysis–based fatigue life prediction and accelerated durability testing of the tilting disc heart valves for nine different valve sizes. First, finite element analysis–based fatigue life prediction showed that all nine valve sizes were in the infinite life region. Second, accelerated durability test showed that all nine valve sizes remained functional for 400 million cycles under experimental conditions. The study ensures the continued function of TC2 model tilting disc heart valves over duration in excess of 50 years. The results imply that the TC2 model valve designs are structurally safe, reliable and durable.

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