Stress distribution analysis of composite repair with Carbon Nanotubes reinforced putty for damaged steel pipeline

Carbon fiber reinforced polymer (CFRP) matrix composite overwrap repair systems have been introduced and accepted as an alternative repair system for steel pipeline. This paper aimed to evaluate the mechanical behavior of damaged steel pipeline with CFRP repair using finite element (FE) analysis. Two different repair strategies, namely wrap repair and patch repair, were considered. The mechanical responses of pipeline with the composite repair system under the maximum allowable operating pressure (MAOP) was analyzed using the validated FE models. The design parameters of the CFRP repair system were analyzed, including patch/wrap size and thickness, defect size, interface bonding, and the material properties of the infill material. The results show that both the stress in the pipe wall and CFRP could be reduced by using a thicker CFRP. With the increase in patch size in the hoop direction, the maximum von Mises stress in the pipe wall generally decreased as the maximum hoop stress in the CFRP increased. The reinforcement of the CFRP repair system could be enhanced by using infill material with a higher elastic modulus. The CFRP patch tended to cause higher interface shear stress than CFRP wrap, but the shear stress could be reduced by using a thicker CFRP. Compared with the fully bonded condition, the frictional interface causes a decrease in hoop stress in the CFRP but an increase in von Mises stress in the steel. The study results indicate the feasibility of composite repair for damaged steel pipeline.

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Stress Distribution Analysis of Different Types of Blade for a Fermentation System

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.479-480.319 ◽

2013 ◽

Vol 479-480 ◽

pp. 319-323

Author(s):

Cheng Chi Wang ◽

Po Jen Cheng ◽

Kuo Chi Liu

Keyword(s):

Stress Distribution ◽

Maximum Stress ◽

Effective Means ◽

Materials Processing ◽

Distribution Analysis ◽

Stress Distributions ◽

Fermentation System ◽

Different Types ◽

Inclined Angle ◽

Key Parameter

Fermentation system is widely used for food manufacturing, materials processing and chemical reaction etc. Different types of blade in the tank for fermentation cause distinct stress distributions on the surface between fluid and blade, and appear various flow fields in the tank. So, this paper is mainly focused on analyzing the stress field of blades under different scales of blade with fixing rotational speed. The results show that the ratio of blade length to width influences stress distribution on the blades. At the same time, the inclined angle of blade is also the key parameter for the consideration of design and appropriate design will decrease the maximum stress. The results provide an effective means of gaining insights into the stress distribution of fermentation system.

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Evaluation of the response of fibre reinforced composite repair of steel pipeline subjected to puncture from excavator tooth

Composite Structures ◽

10.1016/j.compstruct.2018.05.065 ◽

2018 ◽

Vol 202 ◽

pp. 1126-1135 ◽

Cited By ~ 4

Author(s):

Łukasz Mazurkiewicz ◽

Jerzy Małachowski ◽

Krzysztof Damaziak ◽

Michał Tomaszewski

Keyword(s):

Composite Repair ◽

Steel Pipeline ◽

Reinforced Composite ◽

Excavator Tooth

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Residual Stress Prediction by Means of 3D FEM Simulation

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.223.431 ◽

2011 ◽

Vol 223 ◽

pp. 431-438 ◽

Cited By ~ 1

Author(s):

Aldo Attanasio ◽

Elisabetta Ceretti ◽

Cristian Cappellini ◽

Claudio Giardini

Keyword(s):

Residual Stress ◽

Stress Distribution ◽

Stress Measurement ◽

Numerical Models ◽

Orthogonal Cutting ◽

Residual Stress Distribution ◽

Tool Geometry ◽

Distribution Analysis ◽

3D Fem ◽

Workpiece Material

In cutting field, residual stress distribution analysis on the workpiece is a very interesting topic. Indeed, the residual stress distribution affects fatigue life, corrosion resistance and other functional aspects of the workpiece. Recent studies showed that the development of residual stresses is influenced by the cutting parameters, tool geometry and workpiece material. For reducing the costs of experimental tests and residual stress measurement, analytical and numerical models have been developed. The aim of these models is the possibility of forecasting the residual stress distribution into the workpiece as a function of the selected process parameters. In this work the residual stress distributions obtained simulating cutting operations using a 3D FEM software and the corresponding simulation procedure are reported. In particular, orthogonal cutting operations of AISI 1045 and AISI 316L steels were performed. The FEM results were compared with the experimental residual stress distribution in order to validate the model effectiveness.

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Microstructural Evolution and Fracture Mechanism for Scar Defect Formation on Advanced High Strength Steel during a Shearing Process

Journal of Manufacturing Science and Engineering ◽

10.1115/1.4048857 ◽

2020 ◽

pp. 1-22

Author(s):

Onnjira Diewwanit ◽

Paranee Keawcha-um ◽

Thanita Keawcha-um ◽

Weesuda Petchhan ◽

Sutasn Thipprakmas

Keyword(s):

Stress Distribution ◽

Tensile Test ◽

Fracture Mechanism ◽

Defect Formation ◽

Flow Direction ◽

High Strength ◽

Distribution Analysis ◽

Dp Steel ◽

Tensile Test Specimen ◽

Cut Edge

Abstract To form a required shape of the advanced high strength steels especially DP steel sheets, shearing process being one of major processes is commonly used. In general, although the good cut-edge with small fracture could be achieved by setting small shearing clearance, the tearing being a major defect commonly occurred on the cut-edge. Therefore, in the present research, a tearing mechanism on the DP steel sheet, grade SPFC980Y (JIS) during shearing process is investigated and clearly clarified based on the microstructure evolution, fracture mechanism, and stress distribution analysis. The microstructure evolutions on both tensile test specimen and sheared workpiece were performed to clarify the fracture mechanism. The angle between shear band and elongated grain flow direction is examined based on tensile test and it is used to predict an angle of initial fracture and its propagation on the shearing process as well. By associated with stress distribution analysis generated in shearing zone during shearing phase, the results revealed that the fracture propagated out of shearing zone and the fracture could be easily delayed. This resulted in that the tearing could be generated in the case of SPFC980Y. Vice versa, the fracture propagation is all in shearing zone, the fracture could not be delayed and the fracture completely generated on the cut-edge in the case of SPCC. In the present resents, the tearing mechanism on the DP steels in shearing process is clearly characterized.

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Dopant Distribution Analysis in Carbon Nanotubes By Z-Contrast Imaging

Microscopy and Microanalysis ◽

10.1017/s1431927600027112 ◽

2001 ◽

Vol 7 (S2) ◽

pp. 208-209

Author(s):

E.C. Dickey

Keyword(s):

Carbon Nanotubes ◽

Ex Situ ◽

Distribution Analysis ◽

Contrast Imaging ◽

New Class ◽

Transmission Electron ◽

Structural Applications ◽

Donor Type ◽

Scanning Transmission ◽

Z Contrast

Similar to graphite and carbon fullerenes, the physical properties of carbon nanotubes (NTs) can be altered by ex-situ doping or by functionalizing the nanotube walls. Such mechanisms for tailoring the properties of carbon NTs expand their potential utility in electronic, optical and structural applications. Both acceptor (e.g. I2, Br) and donor-type (e.g. K, Rb) dopants have been successfully intercalated into single-wall NT (SWNT) bundles, and the transport properties of these doped species are greatly altered. For example, iodine-doped SWNTs exhibit a 40% decrease in DC conductivity. Doped SWNTs are a completely new class of nanostructured materials, and there is a large demand for understanding the structure of the various doped-compounds as well as the ramifications for the electronic properties of the material.In this paper we demonstrate the utility of Z-contrast scanning transmission electron microscopy (STEM) for elucidating the structure of doped nanotubes.

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