Simulation methodology for the assessment of the structural safety of concrete tunnel linings based on CFD fire – FE thermo-mechanical analysis: a case study

2020 ◽  
Vol 225 ◽  
pp. 111193
Author(s):  
Patrizia Bernardi ◽  
Elena Michelini ◽  
Alice Sirico ◽  
Sara Rainieri ◽  
Carlo Corradi
Keyword(s):  
Mechanical Analysis ◽  
Structural Safety ◽  
Simulation Methodology

scholarly journals Coupled Thermo-Hydro-Mechanical Analysis of Valley Narrowing Deformation of High Arch Dam: A Case Study of the Xiluodu Project in China

2020 ◽  
Vol 10 (2) ◽  
pp. 524 ◽  
Author(s):  
Tao Yin ◽  
Qingbin Li ◽  
Yu Hu ◽  
Sanda Yu ◽  
Guohe Liang
Keyword(s):  
Coupling Effect ◽  
Mechanical Analysis ◽  
Arch Dam ◽  
Water Infiltration ◽  
Structural Safety ◽  
Deformation Pattern ◽  
Field Variation ◽  
High Arch Dam ◽  
Key Factor

General studies examining reservoir bank deformation during its impoundment primarily consider the coupling effect between the seepage field and the stress field, but thermal field variation in the bedrock and its effect are rarely considered. In this paper, a case study concerning a 285.5 m high arch dam project, where a valley narrowing deformation occurs after the initial impoundment, is implemented. An analysis of in situ measurement is given to interpret the causes of the unique hydro-thermal phenomenon of the project. Possible reasons for the valley narrowing deformation pattern are discussed. A numerical model based on the thermo-hydro-mechanical (THM) coupling theory of porous medium is used to calculate the evolution processes of the thermal, seepage, and stress fields of the area after impoundment of the reservoir. The simulated deformation trend and pattern of the river valley are consistent with the monitoring data. The results demonstrate that water infiltration after impounding cools the bedrock and the temperature decrease makes the bedrock contract, which induces the narrowing deformation of the valley. Factor analysis of the hydrothermal field shows that temperature variation is the main cause of long-term deformation. Thus, it shall be considered as a key factor in terms of structural safety assessment. Furthermore, sensitivity analysis of the hydraulic conductivities of rock strata suggests that future development of the deformation can be eased off if the anti-seepage method is adopted on the bedrock.

scholarly journals Roof Movement and Failure Behavior When Mining Extra-Thick Coal Seams Using Upward Slicing Longwall-Roadway Cemented Backfill Technology

2020 ◽  
Vol 2020 ◽  
pp. 1-15 ◽  
Author(s):  
Xuejie Deng ◽  
Zongxuan Yuan ◽  
Lixin Lan ◽  
Benjamin de Wit ◽  
Junwen Zhang
Keyword(s):  
Mechanical Analysis ◽  
Movement Behavior ◽  
Failure Behavior ◽  
Mining Method ◽  
Coal Seams ◽  
Flat Bottom ◽  
Final State ◽  
Performance Requirements ◽  
Cemented Backfill

A novel and environmental-friendly backfill mining method known as upward slicing longwall-roadway cemented backfill (USLCB) technology has recently been proposed and successfully applied in mines extracting extra-thick coal seams located under sensitive areas. This paper studies the effects USLCB had on roof movement and failure behavior using the mechanical analysis approach. The application of USLCB in the Gonggeyingzi Mine is taken as a case study with roof movement behavior being monitored over a single mining cycle, as well as over multiple mining cycles of different coal slices. In addition, backfill performance requirements to prevent roof failures where USLCB is implemented are studied. The results show that the deflection curves of the roof at the end of each mining cycle during mining the first and the six slices are symmetrical, but they change from asymmetrical to symmetrical during the mining progresses of the second slice to the fifth slice. The final state of roof movement after the first slice, and through to the fifth slice, displays an obvious “flat bottom” pattern in the middle of the deflection curve. The roof movement during the removal of the top slice is noticeably different from other slices. The results also show that the requirements of the elastic modulus, as well as the strength of the backfill, increase as the number of mined slices increases from 1 to 5, but the requirements drop sharply for mining the top slice.

scholarly journals Further refinement of the Corbelling Theory for the equilibrium analysis of corbelled domes

2019 ◽  
Vol 6 (1) ◽  
pp. 30-40
Author(s):  
Aguinaldo Fraddosio ◽  
Nicola Lepore ◽  
Mario Daniele Piccioni
Keyword(s):  
Laser Scanner ◽  
Equilibrium Analysis ◽  
Structural Safety ◽  
Structural Behavior ◽  
Thick Shell ◽  
Starting Point ◽  
Further Development ◽  
Load Conditions

Abstract The aim of this paper is to present a further development of the Corbelling Theory [1] for assessing the structural safety of “false domes” constructions like Trulli, and more generally for corbelled domes. In particular, it is well-known that a corbelled dome of a Trullo is a layered thick shell and that only the thin inner layer (candela) has a structural role. The proposed procedure extends the capabilities of the approach proposed in [2] to more general load conditions, including the infill. The effectiveness of the proposed approach is discussed through the analysis of a paradigmatic case study of a Trullo located in Alberobello. Since the geometry of the construction plays a fundamental role in the structural behavior, the starting point of the analysis was an accurate 3D-laser scanner survey of the dome. The obtained results give some interesting insights about the role of the infill load on the equilibrium of such kind of corbelled domes.

scholarly journals As-Built 3D Heritage City Modelling to Support Numerical Structural Analysis: Application to the Assessment of an Archaeological Remain

2019 ◽  
Vol 11 (11) ◽  
pp. 1276 ◽  
Author(s):  
Daniel Antón ◽  
Paloma Pineda ◽  
Benachir Medjdoub ◽  
Alfredo Iranzo
Keyword(s):  
Structural Damage ◽  
Laser Scanning ◽  
Conservation Status ◽  
Geometric Analysis ◽  
Structural Safety ◽  
Cloud Data ◽  
Analysis Application ◽  
Status Analysis ◽  
3D Meshing

Terrestrial laser scanning is a widely used technology to digitise archaeological, architectural and cultural heritage. This allows for modelling the assets’ real condition in comparison with traditional data acquisition methods. This paper, based on the case study of the basilica in the Baelo Claudia archaeological ensemble (Tarifa, Spain), justifies the need of accurate heritage modelling against excessively simplified approaches in order to support structural safety analysis. To do this, after validating the 3D meshing process from point cloud data, the semi-automatic digital reconstitution of the basilica columns is performed. Next, a geometric analysis is conducted to calculate the structural alterations of the columns. In order to determine the structural performance, focusing both on the accuracy and suitability of the geometric models, static and modal analyses are carried out by means of the finite element method (FEM) on three different models for the most unfavourable column in terms of structural damage: (1) as-built (2) simplified and (3) ideal model without deformations. Finally, the outcomes show that the as-built modelling enhances the conservation status analysis of the 3D heritage city (in terms of realistic compliance factor values), although further automation still needs to be implemented in the modelling process.

Case Study of Temperature Analysis Performed on a 45-inch Diameter Heat Exchanger Flange

2005 ◽  
Author(s):  
Warren Brown ◽  
Richard Brodzinski
Keyword(s):  
Heat Exchanger ◽  
Potential Problem ◽  
Mechanical Analysis ◽  
Analytic Method ◽  
Temperature Analysis ◽  
Joint Operation ◽  
Element Analysis ◽  
Methods Of Analysis ◽  
Effects Of Temperature

This paper presents an overview of thermal and mechanical analysis performed on the tubesheet joint of a 45 inch diameter feed/effluent heat exchanger to determine the effects of temperature on the joint operation. Two methods of analysis are used, a new analytical approach and Finite Element Analysis (FEA). The analysis determined a potential problem with the operation of the joint in the intended service and a method of improvement was proposed. Some pitfalls of the methods of analysis, for both the analytic method and FEA, are presented. The comparison between the analytic approach and FEA clearly outlined the advantages of each method in determining the operability of heat exchanger joints.

Axisymmetric Mechanical Behavior of Flexible Risers

2015 ◽  
Author(s):  
Liu Junpeng ◽  
Murilo A. Vaz ◽  
Menglan Duan ◽  
Xiaotian Li
Keyword(s):  
Correspondence Principle ◽  
Mechanical Analysis ◽  
Axial Stiffness ◽  
Prony Series ◽  
Structural Damping ◽  
Flexible Riser ◽  
Damping Behavior ◽  
Polymer Properties ◽  
Flexible Risers

Polymer properties, i.e. viscoelastic characteristics, may pose a non-negligible impact on the axisymmetric analysis, especially on the axial structural damping behavior. An available mechanical model taking viscoelastic into account is established for capturing such parameters as axial strains and forces on each layer, axial stiffness and so on. In this paper, the flexible riser is divided into helical and cylindrical elements to carry out the mechanical analysis due to the complexity of structure and material property. Prony Series is used to describe the creep and relaxation behavior of material viscoelasticity. A viscoelastic solution is obtained using the correspondence principle. Finally, a case study is performed and some interesting results are presented.

scholarly journals Structural Safety Assessment of Marine Operations From a Long-Term Perspective: A Case Study of Offshore Wind Turbine Blade Installation

2019 ◽  
Author(s):  
Amrit Shankar Verma ◽  
Zhen Gao ◽  
Zhiyu Jiang ◽  
Zhengru Ren ◽  
Nils Petter Vedvik
Keyword(s):  
Failure Probability ◽  
Safety Assessment ◽  
Routine Activity ◽  
Structural Safety ◽  
Offshore Wind Turbine ◽  
Structural Failure ◽  
Blade Root ◽  
Extreme Response

Abstract A marine operation is a complex non-routine activity of limited duration carried out in offshore environment. Due to safety reasons, these operations are normally performed within specific sea state limits, which are derived from numerical modelling and analysis of hazardous events. In view of the uncertainties in the assessment of structural responses under stochastic environmental conditions, these limiting curves correspond to a target structural failure probability recommended in offshore standards (for example, 10−4 per operation as specified by DNV-GL). However, one of the main limitations is that these curves do not reflect site-specific safety assessment. The current paper presents a novel methodology for assessing the structural safety level of marine operations from a long-term perspective. The methodology includes estimation of extreme response distribution under all possible operational sea states (i.e. the operational domain under the limiting sea states) for a given offshore site and is compared to the response limit to obtain an average failure probability. A case study is also presented for a blade root mating process onto preassembled hub using a jack-up crane vessel and risk of impact between root and hub is considered critical. Global time-domain simulations are performed using multibody dynamics, and extreme value distributions for impact velocities are derived for different wind-wave conditions. The allowable impact velocity between the blade root and the hub is determined by an explicit finite element analysis of the damage at the blade root. Finally, the average failure probabilities considering the operational domain are obtained for four different European offshore sites and are compared to the target level of structural failure probability considered for the limiting sea states.

Structural Safety and Stability of the Bridge on the Paraopeba River in Moeda, Minas Gerais, Brazil: Case Study

2021 ◽  
Vol 26 (1) ◽  
pp. 05020012
Author(s):  
Elvys Dias Reis ◽  
Diego Luiz Costa e Souza ◽  
Hermes Carvalho ◽  
Pedro A. Montenegro ◽  
Diogo Ribeiro
Keyword(s):  
Minas Gerais ◽  
Structural Safety ◽  
Safety And Stability

A Lifecycle Simulation Method for Global Reuse

2018 ◽  
Vol 12 (6) ◽  
pp. 814-821 ◽  
Author(s):  
Hidenori Murata ◽  
Naoya Yokono ◽  
Shinichi Fukushige ◽  
Hideki Kobayashi ◽  
◽  
...  
Keyword(s):  
Material Flow ◽  
New Products ◽  
Simulation Method ◽  
Environmental Benefits ◽  
Product Lifecycle ◽  
Simulation Methodology ◽  
Control Rules ◽  
Multiple Product ◽  
Over Time

Reuse is an effective method of circulating resources in terms of environmental benefits because it requires fewer resources and less energy than manufacturing new products from virgin materials. In global reuse, a used component or module is reused in a different application. To evaluate a system of multiple product lifecycle systems (PLSs), the lifecycle simulation methodology LCS4SoS has been proposed. LCS4SoS comprises three elements, namely, individual PLSs, interactions among them, and their evolution over time. This paper proposes a lifecycle simulation method for global reuse based on the LCS4SoS framework. Flow control rules are developed for global reuse to control the directions and quantities of material flow among the PLSs. The usefulness of this method is verified by a case study of automobile and stationary battery PLSs.

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