检索结果-南通市图书馆

Numerical Aspects of Isogeometric Boundary Element Methods:(Nearly)Singular Quadrature,Trimmed NURBS and surface crack Modeling

在线全文

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & Sciences 2022年第1期130卷 513-542页

作者： Xuan Peng Haojie Lian Department of Mechanical Engineering Suzhou University of Science and TechnologySuzhou215009China Key Laboratory of In-situ Property-improving Mining of Ministry of Education Taiyuan University of TechnologyTaiyuan030024China

This work presents some numerical aspects of isogeometric boundary element methods(IGABEM).The behavior of hyper-singular and nearly-singular integration is first explored on the distorted NURBS *** numerical treatments are proposed to enhance the quadrature in the framework of isogeometric *** a numerical implementation of IGABEM on the trimmed NURBS is *** on this idea,the surface crack problem is modeled incorporation with the phantom element *** proposed method allows the crack to intersect with the boundary of the body while preserving the original parametrization of the NURBS-based CAD geometry.

关键词： Isogeometric analysis trimmed NURBS singular integration boundary element method surface crack

Monte-Carlo Simulation of surface crack Growth Rate for Offshore Structural Steel E36-Z35

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

China Ocean Engineering 1999年第1期14卷 1-10页

作者： Ding, Keqin Liu, Chuntu Zhao, Junyou Guo, Aiju Chinese Acad Sci Inst Mech Beijing 100080 Peoples R China Petr Univ China Shandong 257012 Peoples R China

The Monte- Carlo method is used to simulate the surface fatigue crack growth rate for offshore structural steel E36-Z35, and to determine the distributions and relevance of the parameters in the Paris equation. By this method, the time and cost of fatigue crack propagation testing can be reduced. The application of the method is demonstrated by use of four sets of fatigue crack propagation data for offshore structural steel E36-Z35. A comparison of the test data with the theoretical prediction for surface crack growth rate shows the application of the simulation method to the fatigue crack propagation tests is successful.

关键词： Monte-Carlo method simulation surface crack crack growth rate offshore structural steel fatigue crack propagation test

SEMI-ELLIPTIC surface crack IN AN ELASTIC SOLID WITH FINITE SIZE UNDER IMPACT LOADING

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2006年第2期19卷 122-127页

作者： Guo Ruiping Liu Guanting Fan Tianyou Academy of Equipment Command and Technology Beijing 101416 China Department of Mathematics Inner Mongolia Normal University Huhhot 010022 China Department of Physics Beijing Institute of Technology Beijing 100081 China

In this paper a semi-elliptic surface crack problem in an elastic solid of finite size under impact loading is investigated. An analysis is performed by means of fracture dynamics and the finite element method, and a three-dimensional finite element program is developed to compute the dynamic stress intensity factor. The results reveal that the effects of the solid＇s boundary surface, crack surface, material inertia and stress wave interactions play significant roles in dynamic fracture.

关键词： surface crack solid of finite size impact loading dynamic stress intensity factor,finite element method

surface crack imaging based on delayed temperature difference at symmetric points by laser spot thermography

在线全文

学校读者我要写书评

暂无评论

Instrumentation 2014年第2期1卷 30-37页

作者： WANG Xiaona WANG Xiaoning HOU Dexin YE Shuliang Institute of Industry and Trade Measurement Technique in China Jiliang University Hangzhou 310018China

Laser spot thermography is a novel technique for the detection of surface cracks with a laser to heat sample locally and with an IR camera to record the surface temperature distribution. Common methods to characterize cracks are only suitable for the situation that the laser scanning path is vertical to the crack. But due to the randomness of cracks,when the scanning path is parallel to the crack,surface cracks cannot be detected by these methods. To tackle this problem,a method is presented which is suitable for the situation that the scanning path is parallel to crack. The main idea is to evaluate the crack-caused asymmetries of the surface temperature distribution. The effect of temperature gradient and the maximum scanning interval are analyzed by a 2D simulation. A new crack imaging technique is presented that is based on delayed temperature difference at symmetric points to characterize the crack in the thermal image. Compared well with those obtained by the spatial first derivative method,experimental results are shown to efficiently prove this method.

关键词： Laser spot thermography Scanning path parallel to crack Delayed temperature difference at symmetric points surface crack

METHOD FOR CALCULATION AND SIMULATION ON PROPAGATION OF surface crack ON SPHERICAL VESSELS MADE OF STEELS

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 1999年第5期12卷 807-810页

作者： T.J.Bai 1,2) and C.F.Ren 1) 1) Shenyang University, Shenyang 110044, China 2) Institute of Metal Research, The Chinese Academy of Sciences,Shenyang 110015, China

To avoid leaking or bursing by crack on surface of preddure vessels made of streels,a method for analyzing the principle of propagation of a surface crack is established,and used on a spherical vessel with program cal... 详细信息

关键词： spherical vessel surface crack propagation J integral

Study on fracture mechanics parameters of surface crack in overmatched weldments

在线全文

学校读者我要写书评

暂无评论

China Welding 1999年第1期8卷 26-32页

作者：李继红张建勋裴怡

In this paper, the J integral of surface cracks in overmatched weldments with different matching ratio has been investigated using direct evaluation method. The influence of matching ratio of joints on the crack driving forces (J integral, crack mouth opening displacement CMOD) and strain distributions along the contour have been discussed in detail. The results indicate that the comprehensive effects of crack position and the matching ratio of welded joint dominate the distribution of strain along the contour. Moreover, the crack driving force increases with the decrease of the matching ratios in overmatched weldments.

关键词： welded joint surface crack J integral

Development of Correlation Between surface crack Size and Corrosion Pit Size for Service Life Prediction

在线全文

学校读者我要写书评

暂无评论

Development of Correlation Between Surface Crack Size and Co...

Investigation on 3D fatigue crack propagation in surface-cracked specimens

2007国际机械工程与力学会议

作者： Keliang REN Guozhi LV Majd-ud-din MUHAMMAD Youhong ZHANG Department of Aeronautical Structural Engineering Northwestern Polytechnical University Department of Physics & Electrical Information Engineering Ningxia University

In order to set up the relation between corrosion pits and equivalent initial surface crack （EISC）, for quantitative assessment of the residual strength of the aging structure in corrosive environment, a series of pre-corroded samples are prepared at different time and temperature, and subsequent fatigue experiments under uniaxial cyclic load have been performed with LY12-CZ Aluminium alloy. After pre-corrosion and fatigue test, the equivalent initial surface crack size is calculated through reverse integration of the Paris fatigue crack growth law and has solved the non-linear equation using Monte Carlo method from the experiment fatigue life. Finally life predictions are made using the pit sizes measured in experiment and EISC size calculated by reverse integration of the Paris fatigue crack growth law as the initial size of surface crack in computer package AFGROW, and compared with the experimented fatigue life. The results show that the size of equivalent initial surface crack is less than 19.7 to 22.5 percent of surface corrosion pit size which has the same life.

关键词： Corrosion pit surface crack Equivalent initial crack Monte Carlo method Aging structure Residual strength AFGROW

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Theoretical & Applied Mechanics Letters 2013年第4期3卷 18-22页

作者： X.Li H.Yuan J.Y.Sun Department of Mechanical Engineering University of Wuppertal

In the present work the fatigue crack growth in AISI304 specimens is investigated experimentally. In 3D finite element analysis the virtual crack closure technique is applied to calculate distributions and variations of the stress intensity factor along the surface crack front. It is confirmed that the stress intensity factor along the surface crack front varies non-uniformly with crack growth. crack growth rate is proportional to the stress intensity factor distribution in the 3D cracked specimen. The fatigue crack growth in surface cracked specimens can be described by the Forman model identified in conventional compact tension specimens. For crack growth in the free specimen surface the arc length seems more suitable to quantify crack progress. Geometry and loading configuration of the surface cracked specimen seem to not affect the fatigue crack growth substantially.

关键词： surface crack crack front fatigue crack growth 3D stress intensity factor

Influence of surface cracking,anchor head profile,and anchor head size on cast-in headed anchors in geopolymer concrete

在线全文

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil Engineering 2023年第8期17卷 1163-1187页

作者： Trijon KARMOKAR Alireza MOYHEDDIN School of Engineering Edith Cowan UniversityPerth 6027Australia

In this study,the concrete cone capacity,concrete cone angle,and load–displacement response of cast-in headed anchors in geopolymer concrete are explored using numerical *** concrete damaged plasticity(CDP)model in ABAQUS is used to simulate the behavior of concrete *** tensile behavior of anchors in geopolymer concrete is compared with that in normal concrete as well as that predicted by the linear fracture mechanics(LFM)and concrete capacity design(CCD)*** results show that the capacity of the anchors in geopolymer concrete is 30%–40%lower than that in normal *** results also indicate that the CCD model overestimates the capacity of the anchors in geopolymer concrete,whereas the LFM model provides a much more conservative *** extent of the difference between the predictions by the numerical analysis and those of the above prediction models depends on the effective embedment depth of the anchor and the anchor head *** influence of concrete surface cracking on the capacity of the anchor is shown to depend on the location of the crack and the effective embedment *** influence of the anchor head profile on the tensile capacity of the anchors is found to be insignificant.

关键词： cast-in anchor concrete cone capacity geopolymer concrete head size surface crack anchor profile