Assessment Procedures for Mechanical Securing Components of LNG Cargo Containment System With Potential Damages

2016 ◽  
Author(s):  
Sung-In Cho ◽  
Jung-Oh Hwang ◽  
Chang-Seon Bang ◽  
Jun-Hong Bae
Keyword(s):  
Visual Inspection ◽  
Structural Integrity ◽  
Time History ◽  
Fem Analysis ◽  
Static Tests ◽  
Vibrational Loading ◽  
Containment System ◽  
Endurance Tests ◽  
Resonance Search ◽  
Loading Tests

This research has been performed to evaluate the structural integrity of the LNG cargo containment system. The structural integrity under vibrational loading and hull deflection was evaluated for damaged and undamaged systems. The test Mock-ups had been constructed for vibrational loading tests and hull deflection tests to compare the system behaviors under the damaged and the undamaged conditions. The damaged Mock-up was constructed with particular damages at the mechanical joints of the top and the bottom boards. The damages of the joints were applied at the designated points, which were selected based on the FEM analysis that compares the stress levels for the various damaged systems. The static tests were performed when the bottom board and the top board was installed, respectively. The visual inspection had been performed to compare the structural integrity of the damaged and the undamaged system during and after the tests. The vibrational loading tests had also been performed to compare the fatigue performance of both the damaged and the undamaged system. Endurance tests were performed for both vertical and lateral directions based on the results of resonance search tests. The specimens were vibrated at the resonant frequencies determined to most seriously affect the structural integrity. Abnormality of the acceleration time history had been monitored during the endurance tests and the acceleration level at the beginning of the test was compared with the level at the end of the test. After the endurance tests, the structural integrity of both systems had been thoroughly investigated by visual inspection.

A Development of the Visco-Elastic Damper for Timber Structure and a Suggestion of the Technological Design Assistance System

2013 ◽  
Vol 778 ◽  
pp. 714-721
Author(s):  
Katsuhiko Kohara ◽  
Takeshi Nomura ◽  
Kazuyoshi Koumoto
Keyword(s):  
Seismic Response ◽  
Elastic Body ◽  
Structural Model ◽  
Time History ◽  
Timber Structure ◽  
Response Analysis ◽  
Frame Design ◽  
Timber Frame ◽  
Loading Tests ◽  
Controlled Structure

Our research team developed a brace type and an angle brace type of the visco-elastic damper on seismic-response controlled structure for timber structure. We performed various dependence evaluations by the materials examination of the styrene olefin-based visco-elastic body which we developed newly. We made a structural model using the performance that loading tests in timber frame. We inspected the validity of the structural model. In addition, we built a technical support system for damper setting by the time history response analysis so that a general design architect was easy to use the damper. We could express dynamics properties of visco-elastic body properties by Voigt model, and the structural model almost accorded with an examination property value. We made a structural model of the whole frame system by Kb of installation rigidity obtained from loading tests in timber frame. Because a design level almost accorded with experimental value, the validity of the frame design on seismic-response controlled structure in consideration of the dependence (distortion, frequency, temperature) of the visco-elastic body was confirmed. This visco-elastic damper on seismic-response controlled structure acquired minister authorization of Ministry of Land, Infrastructure and Transport. In addition, this damper acquired the certification of the Japan Building Disaster Prevention Association.

Investigation on Effect of Analysis Variables on Structural Integrity of the Nuclear Piping Under Beyond Design Basis Earthquake

2017 ◽  
Author(s):  
Jong-Sung Kim ◽  
Suk-Hyun Lee ◽  
Hyeong Do Kweon
Keyword(s):  
Finite Element ◽  
Structural Integrity ◽  
Seismic Analysis ◽  
Time History ◽  
Time History Analysis ◽  
Design Basis ◽  
History Analysis ◽  
Study Results ◽  
Transition Length ◽  
Dynamic Time

In this study, effect of analysis variables on structural integrity of nuclear piping under beyond design basis earthquake was investigated via performing dynamic time history seismic analysis. A finite element model of the piping system such as shut-down cooling line was developed combining solid and beam elements. Dynamic time history analysis was performed via finite element elastic plastic stress analysis. Validity of the dynamic time history analysis procedure was verified via comparing with the previous study results. Finally, the effect of analysis variables such as finite element characteristics, transition length between elbow and straight line, fluid effect, etc. was investigated via performing parametric dynamic time history seismic analysis. As a result, it was found that use of the 1st incompatible element is recommended, the transition length is the same as curvature of the elbow, and fluid has to be considered.

Virtual Prototype Based Fatigue Life Research on some Missile Erecting System

2013 ◽  
Vol 706-708 ◽  
pp. 1676-1679
Author(s):  
Chang Lin Hu ◽  
Li Yuan Ma ◽  
Hui Li ◽  
Yong Jun Li
Keyword(s):  
Fatigue Life ◽  
Time History ◽  
Fem Analysis ◽  
Virtual Prototype ◽  
Ballistic Missile ◽  
Damage Analysis ◽  
Load Spectrum ◽  
Material Fatigue ◽  
System Components

With some ballistic missile erecting system as subject, a virtual prototype is constructed, for virtual measuring of the load spectrum of the erecting system. By FEM analysis and damage analysis, the dangerous position of is uncovered, and the stress-time history is obtained. By use of material fatigue feature curve in combination with the stress-time history, the fatigue life of system components is studied.

Static Loading Tests of New Type of Bolt Assembly Connection Developed for Perspective Temporary Steel Railway Bridges

2014 ◽  
Vol 590 ◽  
pp. 331-335 ◽  
Author(s):  
Marcela Karmazínová ◽  
Michal Štrba
Keyword(s):  
Numerical Modelling ◽  
Failure Mechanism ◽  
Static Loading ◽  
Fatigue Loading ◽  
Preliminary Evaluation ◽  
Problem Solution ◽  
Static Tests ◽  
Actual Behaviour ◽  
Loading Tests ◽  
Plate Connections

The paper deals with the problems of the actual behaviour, failure mechanism and load-carrying capacity of the special bolt connection developed and intended for the assembly joints of the truss main girders chords of perspective railway steel temporary bridges. Within the framework of this problem solution, several types of structural details of assembly joints have been considered as the conceptual structural design. Based on the preliminary evaluation of advantages or disadvantages of these ones, in principle two basic structural configurations – so-called “tooth” and “splice plate” connections have been selected for the subsequent detailed investigation. This investigation is mainly based on the experimental verification of the actual behaviour, strain and failure mechanism and corresponding strength of the connection, and on its numerical modelling using FEM. This paper is focused only on the static loading tests results of the splice plate connections and their evaluation, which have already been finished. Simultaneously with the static tests, the fatigue loading tests are being realized, too, but they have not been finished so far, as well as the FEM numerical modelling.

Experimental Investigation of Invar Edge Effect in Membrane LNG Tanks

2012 ◽  
Vol 134 (3) ◽  
Author(s):  
Mateusz Graczyk ◽  
Kjetil Berget ◽  
Joachim Allers
Keyword(s):  
Fluid Motion ◽  
Structural Response ◽  
Time History ◽  
Pressure Profile ◽  
Pressure Effects ◽  
Local Pressure ◽  
Temporal And Spatial Distribution ◽  
Containment System ◽  
Time Histories ◽  
Liquid Natural Gas

Sloshing, a violent fluid motion in tanks is of current interest for many branches of the industry, among them gas shipping. Although different methods are commonly combined for analyzing sloshing in liquid natural gas (LNG) carriers, time histories of the pressure in the tanks are most reliably obtained by experiments. Very localized pressures may be important for the structural response of the tank containment system. Moreover, the typical pressure time history duration is similar to the structural natural frequency. Therefore, pressure measurements need to be performed with due account for temporal and spatial distribution. This requires a high sampling resolution both in time and space. Fine spatial resolution becomes especially important when local pressure effects are of interest, such as pressure profile passing a membrane corrugation of Mark III containment or Invar edge of No. 96 containment. In this paper experimental approach applied by MARINTEK for analyzing sloshing phenomenon is presented. The focus is put on investigating effects of Invar edges. A transverse 2D model of a typical LNG carrier is used. Local pressure effects are investigated based on low filling level tests with different wall surfaces: smooth and with horizontal protrusions representing the surface similar to the No. 96 containment system.

Quality Assurance of Laser Welded Axisymmetric Sandwich Structure

2013 ◽  
Vol 549 ◽  
pp. 529-534 ◽  
Author(s):  
Kimmo Illikainen ◽  
Kalle Holappa ◽  
Kari Mäntyjärvi
Keyword(s):  
Quality Assurance ◽  
Working Conditions ◽  
Sandwich Structure ◽  
Visual Inspection ◽  
Experimental Tests ◽  
The Body ◽  
Destructive Testing ◽  
Great Strength ◽  
Static Tests

This study focuses on quality assurance in a laser welded axisymmetric sandwich structure that functions as the body of an electric machine. The manufacturing quality of the structure was measured using destructive testing and visual inspection. The destructive tests included both fatigue and static tests in addition to a macrographic examination. The visual inspection comprised ocular estimates of the laser welded seams as well as their requirements. Compared with the real working conditions of the machine, the experimental tests were exhaustive. Nevertheless, in the tests, the bodies held up very well which shows the great strength of the structure.

Experimental Investigation of Invar Edge Effect in Membrane LNG Tanks

2010 ◽  
Author(s):  
Mateusz Graczyk ◽  
Kjetil Berget ◽  
Joachim Allers
Keyword(s):  
Fluid Motion ◽  
Structural Response ◽  
Time History ◽  
Pressure Profile ◽  
Pressure Effects ◽  
Local Pressure ◽  
Temporal And Spatial Distribution ◽  
Containment System ◽  
Pressure Time ◽  
Time Histories

Sloshing, a violent fluid motion in tanks is of current interest for many branches of the industry, among them gas shipping. Although different methods are commonly combined for analyzing sloshing in LNG carriers, time histories of the pressure in the tanks are most reliably obtained by experiments. Very localized pressures may be important for the structural response of the tank containment system. Moreover, the typical pressure time history duration is similar to the structural natural frequency. Therefore, pressure measurements need to be performed with due account for temporal and spatial distribution. This requires a high sampling resolution both in time and space. Fine spatial resolution becomes especially important when local pressure effects are of interest, such as pressure profile passing a membrane corrugation of Mark III containment or Invar edge of No.96 containment. In this paper experimental approach applied by MARIN-TEK for analyzing sloshing phenomenon is presented. The focus is put on investigating effects of Invar edges. A transverse 2D model of a typical LNG carrier is used. Local pressure effects are investigated based on low filling level tests with different wall surfaces: smooth and with horizontal protrusions representing the surface similar to the No.96 containment system.

scholarly journals Structural Reliability Estimation with Participatory Sensing and Mobile Cyber-Physical Structural Health Monitoring Systems

2019 ◽  
Vol 9 (14) ◽  
pp. 2840 ◽  
Author(s):  
Ekin Ozer ◽  
Maria Q. Feng
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Structural Reliability ◽  
Time History ◽  
Fem Analysis ◽  
Modal Identification ◽  
Performance Criteria ◽  
Participatory Sensing ◽  
Structural Health ◽  
Demand Distribution

With the help of community participants, smartphones can become useful wireless sensor network (WSN) components, form a self-governing structural health monitoring (SHM) system, and merge structural mechanics with participatory sensing and server computing. This paper presents a methodology and framework of such a cyber-physical system (CPS) that generates a bridge finite element model (FEM) integrated with vibration measurements from smartphone WSNs and centralized/distributed computational facilities, then assesses structural reliability based on updated FEMs. Structural vibration data obtained from smartphones are processed on a server to identify modal frequencies of an existing bridge. Without design drawings and supportive documentation but field measurements and observations, FEM of the bridge is drafted with uncertainties in the structural mass, stiffness, and boundary conditions (BCs). Then, 2700 FEMs are autonomously generated, and the baseline FEM is updated by minimizing the error between the crowdsourcing-based modal identification results and the FEM analysis. Furthermore, using 151 strong ground motion records from databases, the bridge response time history simulations are conducted to obtain displacement demand distribution. Finally, based on reference performance criteria, structural reliability of the bridge is estimated. Integrating the cyber (FEM analysis) and the physical (the bridge structure and measured vibration characteristics) worlds, this crowdsourcing-based CPS can provide a powerful tool for supporting rapid, remote, autonomous, and objective infrastructure-related decision-making. This study presents a new example of the emerging fourth industrial revolution from structural engineering and SHM perspective.

FEM Analysis on Concrete Column Confined by Straps of BFRP Sheets

2013 ◽  
Vol 639-640 ◽  
pp. 1083-1086
Author(s):  
Xiao Kun Wang ◽  
Hua Xin Liu ◽  
Xue Zhi Wang ◽  
Cheng Zhai
Keyword(s):  
Compressive Strength ◽  
Axial Loading ◽  
Fem Analysis ◽  
High Strength ◽  
Confined Concrete ◽  
Concrete Column ◽  
Good Resistance ◽  
Axial Compressive Strength ◽  
Loading Tests ◽  
Strength And Ductility

More attention has been paid on the technology of BFRP in civil engineering due to it’s unique properties, such as high strength-to-weight radio, good resistance to corrosion and convenient to construction. In order to study the properties of BFRP sheets confined concrete column ,we did it through three groups of columns subjected to axial loading tests and FEM analyses, mainly considering the effect of spacing of straps of BFRP sheets confining concrete column.The results shows that the axial compressive strength and ductility of concrete column winded by BFRP straps have all increased and the process of destruction of concrete column wrapped by BFRP is longer than that of the unconfined concrete column.

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