Effects of Local Metal Loss on Deformability of Line Pipes Subjected to Compressive Load

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Yoshikazu Hashimoto ◽  
Naoto Hagiwara ◽  
Hiroshi Yatabe ◽  
Noritake Oguchi

In this paper, the deformability of line pipe with local metal loss was examined. A full-scale experiment and a finite element (FE) analysis were carried out for line pipe with local metal loss subjected to an axial compressive load. As a result, a good agreement was obtained between the analytical and experimental results. This indicated that the present analytical method was applicable to evaluate the deformability of line pipes with local metal loss subjected to a large ground movement. Parametric studies were then conducted to clarify the relationship between the geometry of the local metal loss and the deformability using the FE analytical method.

Author(s):  
Yoshikazu Hashimoto ◽  
Hiroshi Yatabe ◽  
Naoto Hagiwara ◽  
Noritake Oguchi

In this paper, the deformability of line pipe with local metal loss was examined. A full-scale experiment and a finite element (FE) analysis were carried out for line pipe with local metal loss subjected to an axial compressive load. As a result, a good agreement was obtained between the analytical and experimental results. This indicated that the present analytical method was applicable to evaluate the deformability of line pipes with local metal loss subjected to a large ground movement. Parametric studies were then conducted to clarify the relationship between the geometry of the local metal loss and the deformability using the FE analytical method.


Author(s):  
Masataka Miwa ◽  
Noritake Oguchi ◽  
Yutaka Okajima ◽  
Takayuki Kurobe

Cyclic deformability of steel pipes with local metal loss was studied. Full-scale tests were conducted using X42 and X52 pipes with diameters of 762.0 to 609.6mm. Each test pipe specimen contained an artificial metal loss of rectangular shape and uniform depth on the external surface, and inner pressure and cyclic axial strains were applied with constant amplitudes up to 7 cycles. Buckling deformation was observed in the metal loss region during compressive loading, and it induced a load reduction. The experimental results were analyzed by cyclic elastoplastic FE analysis. The effectiveness of the FE analysis was validated and parametric studies were performed. Buckling was strongly affected by the dimensions of the defect. Through these experiments and FE analyses, we suggested fitness-for-service criteria for buried pipes with external metal loss, taking into account large ground movement during strong earthquakes. Similarly, we examined the aseismic performance of three repair methods for the metal loss region—patch-welding, full-encirclement hot sleeve and weld deposition—through full-scale tests using X42 and X52 pipes with a 609.6mm diameter. We found that patch-welding and weld deposition performed sufficiently well, while the sleeve on the pipe induced buckling near the circumferential fillet weld due to constraint in the radial direction.


2015 ◽  
Vol 776 ◽  
pp. 313-318
Author(s):  
Muhammad Zubair Muis Alie ◽  
Y.R. Palentek ◽  
D.G. Sesa

One of the most important criterion in the design of fixed offshore platform is to have strength from applied loads which is acting perpendicular to jacket leg section such as axial compression.The axial compressive load acts vertically downward to jacket legs and the deformation on the jacket legs in horizontal direction due to this load is called buckling. In the present study, buckling analysis on pechiko field of fixed offshore platform is performed using Finite Element Analysis (FEA). The fixed jacket platform namely tripod and tetrapod are taken as the object of the analysis. Only the axial compressive load is used in the analysis and the boundary conditions are assumed to be fixed both tripod and tetrapod at the bottom seabed. As a fundamental case, buckling analysis is carried out in plane-section (2D analysis), then the result obtained by FE analysis is compared with the analytical solution.It is found that the result obtained by FE analysis for the critical buckling load is in good agreement with the analytical solution, and the applicability of FE analysis is further used to investigate the deformation of 3D model.


2014 ◽  
Vol 610 ◽  
pp. 35-39
Author(s):  
Kai Cheng Yao ◽  
Dong Hua Zhou ◽  
Wen Yuan Liao ◽  
Long Qi Li ◽  
Guo Fei Li ◽  
...  

Based on the assumption of plane section, ideal elastic-plastic model of steel and the constitutive relations of concrete in Chinese Code for Design of Concrete Structures, numerical method is used to analyze the relationship of the axial force-moment-curvature on RC section. After dividing the normal section into strips, we adopt the secant stiffness iteration method (according to the results of each iteration, modify the secant stiffness through changing the elastic modulus of materials) to compile computer program. The results of the paper show a good agreement with those of the analytical method. Comparing with the analytical method, the numerical method of the paper can be wildly used in the application.


Author(s):  
Ryou Kurosawa ◽  
Toshiyuki Sawa ◽  
Yuya Omiya ◽  
Takashi Kobayashi ◽  
Kentaro Temma

The bolted connections inserting gasket such as circular flange connections have been widely used in mechanical structures, which is nuclear and chemical industry, and so on. They are usually used under internal pressure. And they are required the high sealing performance. In the circular flange with non-asbestos compressed sheet gaskets, the two flange surfaces, raised-face and flat-face, are used. The raised-face flange on the sealing performance is examined by many researchers and reported. The flat-face is well known that flange rotation is smaller than that in raised-face flange under the internal pressure. However the sealing performance of the flat-face flange connection isn’t examined. Thus, the sealing performance of the flat-face flange connection is not examined. In this paper, the contact gasket stresses of these connections under internal pressure are analyzed using the finite element method (FEM) of each flange surfaces, taking into account a hysteresis in the stress-displacement curve of the gasket. And then, using the contact gasket stress distributions obtained from FE analysis and the relationship between gasket stress and leak rate obtained from a gasket sealing test (JIS B2490), method for estimating an amount of leakage is examined. The leakage tests were also conducted to measure an amount of gas leakage using an actual circular flange connection with a gasket. The estimated results are in a fairly good agreement with the experimental results.


TAPPI Journal ◽  
2009 ◽  
Vol 8 (6) ◽  
pp. 24-28
Author(s):  
CORY JAY WILSON ◽  
BENJAMIN FRANK

TAPPI test T811 is the specified method to ascertain ECT relative to box manufacturer’s certification compliance of corrugated fiberboard under Rule 41/ Alternate Item 222. T811 test sample heights were derived from typical board constructions at the time of the test method’s initial development. New, smaller flute sizes have since been developed, and the use of lighter weight boards has become more common. The T811 test method includes sample specifications for typical A-flute, B-flute, and C-flute singlewall (and doublewall and triplewall) structures, but not for newer thinner E-flute or F-flute structures. This research explores the relationship of ECT sample height to measured compressive load, in an effort to determine valid E-flute and F-flute ECT sample heights for use with the T811 method. Through this process, it identifies challenges present in our use of current ECT test methods as a measure of intrinsic compressive strength for smaller flute structures. The data does not support the use of TAPPI T 811 for ECT measurement for E and F flute structures, and demonstrates inconsistencies with current height specifi-cations for some lightweight B flute.


1997 ◽  
Vol 24 ◽  
pp. 181-185 ◽  
Author(s):  
Katsuhisa Kawashima ◽  
Tomomi Yamada

The densification of water-saturated firn, which had formed just above the firn-ice transition in the wet-snow zone of temperate glaciers, was investigated by compression tests under pressures ranging from 0.036 to 0.173 MPa, with special reference to the relationship between densification rate, time and pressure. At each test, the logarithm of the densification rate was proportional to the logarithm of the time, and its proportionality constant increased exponentially with increasing pressure. The time necessary for ice formation in the firn aquifer was calculated using the empirical formula obtained from the tests. Consequently, the necessary time decreased exponentially as the pressure increased, which shows that the transformation from firn in ice can be completed within the period when the firn aquifer exists, if the overburden pressure acting on the water-saturated firn is above 0.12–0.14 MPa. This critical value of pressure was in good agreement with the overburden pressure obtained from depth–density curves of temperate glaciers. It was concluded that the depth of firn–ice transition was self-balanced by the overburden pressure to result in the concentration between 20 and 30 m.


2011 ◽  
Vol 24 (6) ◽  
pp. 777-788 ◽  
Author(s):  
J.Z. Liang

The structure of the interlayer between matrix and inclusions affect directly the mechanical and physical properties of inorganic particulate-filled polymer composites. The interlayer thickness is an important parameter for characterization of the interfacial structure. The effects of the interlayer between the filler particles and matrix on the mechanical properties of polymer composites were analyzed in this article. On the basis of a simplified model of interlayer, an expression for estimating the interlayer thickness ([Formula: see text]) was proposed. In addition, the relationship between the [Formula: see text] and the particle size and its concentration was discussed. The results showed that the calculations of the [Formula: see text] and thickness/particle diameter ratio ([Formula: see text]) increased nonlinearly with an increase of the volume fraction of the inclusions. Moreover, the predictions of [Formula: see text] and the relevant data reported in literature were compared, and good agreement was found between them.


2015 ◽  
Vol 645-646 ◽  
pp. 70-74 ◽  
Author(s):  
Min Zhong ◽  
Yu Hang Zhao ◽  
Shou Mian Chen ◽  
Ming Li ◽  
Shao Hai Zeng ◽  
...  

An embedded SiGe layer was applied in the source/drain areas (S/D) of a field-effect transistor to boost the performance in the p channels. Raised SiGe S/D plays a critical role in strain engineering. In this study, the relationship between the SiGe overfilling and the enhancement of channel stress was investigated. Systematic technology computer aided design (TCAD) simulations of the SiGe overfill height in a 40 nm PMOS were performed. The simulation results indicate that a moderate SiGe overfilling induces the highest stress in the channel. Corresponding epitaxial growth experiments were done and the obtained experimental data was in good agreement with the simulation results. The effect of the SiGe overfilling is briefly discussed. The results and conclusions presented within this paper might serve as useful references for the optimization of the embedded SiGe stressor for 40 nm logic technology node and beyond.


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