Structure Mechanics Analysis with Different Construction Schemes in Large-Span Space Grid Structure

2013 ◽  
Vol 788 ◽  
pp. 534-537 ◽  
Author(s):  
Zhen Xing Li
Keyword(s):  
Great Influence ◽  
Construction Method ◽  
Quality And Safety ◽  
Grid Structure ◽  
Large Span ◽  
Construction Scheme ◽  
Space Grid ◽  
Mechanics Analysis ◽  
Practical Engineering ◽  
Selection Of

Different construction schemes in the same construction method have great influence on structure mechanics of grid structure, which is very important for the security and stability in large-span space grid structure. So in order to guarantee the quality and safety of the structure during construction, the selection of construction scheme is particularly important. In this paper, the following practical engineering is adopted to discuss characteristics of different construction schemes in large-span space grid structure and provide a reference for what construction scheme should be selected in the installation of similar space grid structures.

scholarly journals Numerical Simulation on the Response of Adjacent Underground Pipelines to Super Shallow Buried Large Span Double-Arch Tunnel Excavation

2022 ◽  
Vol 12 (2) ◽  
pp. 621
Author(s):  
Jianxiu Wang ◽  
Ansheng Cao ◽  
Zhao Wu ◽  
Zhipeng Sun ◽  
Xiao Lin ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Relative Position ◽  
Great Influence ◽  
Construction Method ◽  
Horizontal Distance ◽  
Large Span ◽  
Underground Pipelines ◽  
Key Factor ◽  
Stress And Deformation ◽  
Pipeline Wall

The excavation of a shallow buried tunnel may cause stress redistribution in surrounding rock, and cause deformation, damage, and even destruction of adjacent underground pipelines. The land part of the Haicang undersea tunnel in Xiamen of China was a super shallow buried large span double-arch tunnel. Its construction was restricted by both underground excavation safe and adjacent pipeline protection. Multiple groups of working conditions were designed considering the relative position of pipe and tunnel, pipeline and tunnel construction parameters. Numerical simulation was used to study the influence of pipeline horizontal distance, buried depth, pipeline diameter, pipeline wall thickness, pipeline shape, pipeline material and excavation method on the response of adjacent underground pipelines. The results show that the relative position of pipe and tunnel, and the construction method of the double-arch tunnel have a great influence on pipeline deformation. Pipeline material, pipeline diameter and excavation method have a great influence on pipeline stress. The construction method was the key factor affecting the stress and deformation of the pipeline. The three-step reserved core soil method can effectively control the stress and deformation of underground pipelines. The research results can provide a reference for similar projects.

scholarly journals Strain Accommodations among Twin Variants in Ti and Mg

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 453
Author(s):  
Ping Zhou ◽  
Guo-Zhen Zhu
Keyword(s):  
Mechanical Property ◽  
Great Influence ◽  
Local Strain ◽  
Deformation Texture ◽  
Variant Selection ◽  
Slip Systems ◽  
Twinning Shear ◽  
Active Variant ◽  
Shed Light ◽  
Selection Of

The selection of twin variants has a great influence on deformation texture and mechanical property in hcp metals where slip systems are limited and twinning types are abundant during deformation. Local strain accommodations among twin variants are considered to shed light on variant selection rules in Ti and Mg alloys. Five kinds of strain accommodations are discussed in terms of different regions that are affected by the twinning shear of primary twin. These regions contain (I) the whole sample, (II) neighboring grain, (III) adjacent primary twin in neighboring grain, (IV) adjoining primary twin within the same parent grain, and (V) multi-generation of twinning inside the primary twin. For a potentially active variant, its operation needs not only relatively higher resolved shear stress but also easily accommodated strain by immediate vicinity. Many of the non-Schmid behaviors could be elucidated by local strain accommodations that variants with relatively higher SFs hard to be accommodated are absent, while those with relatively lower SFs but could be easily accommodated are present.

scholarly journals Evaluation and Selection of Integrated Energy System Construction Scheme Equipped with Smart Energy Management and Control Platform Using Single-Valued Neutrosophic Numbers

2021 ◽  
Vol 13 (5) ◽  
pp. 2615
Author(s):  
Junqing Wang ◽  
Wenhui Zhao ◽  
Lu Qiu ◽  
Puyu Yuan
Keyword(s):  
Energy Management ◽  
Evaluation Criteria ◽  
Energy System ◽  
System Construction ◽  
Interval Numbers ◽  
Construction Scheme ◽  
Smart Energy Management ◽  
Integrated Energy System ◽  
And Control ◽  
Selection Of

Since application of integrated energy systems (IESs) has formed a markedly increasing trend recently, selecting an appropriate integrated energy system construction scheme becomes essential to the energy supplier. This paper aims to develop a multi-criteria decision-making model for the evaluation and selection of an IES construction scheme equipped with smart energy management and control platform. Firstly, a comprehensive evaluation criteria system including economy, energy, environment, technology and service is established. The evaluation criteria system is divided into quantitative criteria denoted by interval numbers and qualitative criteria. Secondly, single-valued neutrosophic numbers are adopted to denote the qualitative criteria in the evaluation criteria system. Thirdly, in order to accommodate mixed data types consisting of both interval numbers and single-valued neutrosophic numbers, the TOPSIS (Technique for Order Preference by Similarity to an Ideal Solution) method is extended into a three-stage technique by introducing a fusion coefficient μ. Then, a real case in China is evaluated through applying the proposed method. Furthermore, a comprehensive discussion is made to analyze the evaluation result and verify the reliability and stability of the method. In short, this study provides a useful tool for the energy supplier to evaluate and select a preferred IES construction scheme.

The Seismic Damage Investigation and Phenomenon Analysis of Space Grid Structures in Lushan Ms 7.0 Earthquake

2014 ◽  
Vol 501-504 ◽  
pp. 1535-1541 ◽  
Author(s):  
Jue Hui Xing ◽  
Ming Lu ◽  
Hai Wang Li ◽  
Ya Min Zhao ◽  
Yan Yu
Keyword(s):  
Seismic Design ◽  
Shell Structure ◽  
Historical Earthquakes ◽  
Seismic Damage ◽  
Grid Structure ◽  
Paper Briefly ◽  
Space Grid ◽  
Reticulated Shell Structure ◽  
Ball Joints ◽  
Damage Investigation

People remained optimistic about the safety of the space grid structures, because the seismic damages of space grid structures were quite rare and rather light. However, two space grid structures got damaged in 2013 Lushan Ms 7.0 earthquake. The two structures are the double-layer reticulated shell structure and flatbed grid structure, namely Lushan Gymnasium and Lushan Middle School Gymnasium respectively. This paper briefly reviews the seismic damage phenomena of grid structures in historical earthquakes, and then focuses on the two damaged space grid structures in Lushan earthquake. The reason why the two space grid structures got damaged are derived from the force state analysis of the rods, ball joints and bearings. Finally, we come up with the effective advice for the seismic design and construction of the space grid structure.

The Optimal Selection of Extrusion Parameters of As-Cast TC27 Titanium Alloy Based on Processing-Map

2017 ◽  
Vol 898 ◽  
pp. 1134-1139
Author(s):  
Xue Fei Li ◽  
Ai Xue Sha ◽  
Xu Huang ◽  
Li Jun Huang
Keyword(s):  
Titanium Alloy ◽  
Flow Stress ◽  
Strain Rate ◽  
Processing Map ◽  
True Strain ◽  
Great Influence ◽  
Stable Condition ◽  
Dynamic Materials ◽  
Dynamic Materials Model ◽  
Selection Of

The hot deformation behavior of TC27 titanium alloy at the temperatures of 900-1150 °C and the strain rate of 0.01-10 s-1, the height reduction of 70%, was investigated in the isothermal compression test to identify the optimal extrusion parameters. The processing-map of TC27 titanium alloy was constructed based on dynamic materials model (DMM) and principle of Prasad*s instability. The conclusion shows that temperature and strain rate of deformation had a great influence on flow stress. At the beginning of deformation, the flow stress increased quickly with the augment of true strain and decreased slowly after flow stress reaching to the maximum value. Finally, flow stress tended to relatively stable condition. The flow stress decreased with the increase of temperature and increased with the increase of strain rate. The TC27 titanium alloy was sensitive to temperature and strain rate. Processing-map exhibited two peak efficiencies of power dissipation; one peak was 49% at 900°C/0.01 s-1, which dynamic recovery occured. The other peak was also 49% at 1050 °C /0.01s-1, which dynamic recrystallization occured in the domain. Besides, there were two instability areas in the processing-map which should be avoided during the extrusion. Therefore, in order to obtain the satisfactory properties, the parameters that 1050 °C and 0.01 s-1 were selected in the extrusion.

Superior Research for Selection of Bracing Structure of Deep Pit Foundation Based on Fussy Theory

2013 ◽  
Vol 838-841 ◽  
pp. 214-218
Author(s):  
Dong Li
Keyword(s):  
General Model ◽  
Engineering Application ◽  
Hard Work ◽  
Deep Foundation ◽  
Scientific Methods ◽  
Deep Pit ◽  
Practical Engineering ◽  
Fuzzy Math ◽  
Selection Of

Before the construction of the deep pit foundation, we must choose a project. Although there aren't many projects to be chosen as usual, we often feel that it's a very complex and hard work. Actually there is no a mature and general model to use. In this paper, the author attempted to use the theory of fuzzy math to establish a former to select the best project, meanwhile provided two ways to solve how to quantify the qualitative targets and how to determine the weights of the targets. Finally they were confirmed to be useful and successful by a practical engineering application. It is worthily to popularize these scientific methods in construction and management in deep foundation pits.

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