Study on the Key Technology of Membrane Roof Structure of Expo Axis in 2010 Shanghai World Expo

The large scale cable-membrane structure is widely used in the Expo Axis. The structure is composed of continuous triangle shaped membrane unit. The representative local part of membrane structure is selected to carry out double-layer membrane strength experiment and reduced-scale experiment to test its mechanical performance and strength index during tension. The results show that the bearing capacity of double-layer membrane structure is more than 1.8 times of single-layer membrane. Material strength and joint strength are all in agreement with the design. Through the analysis of membrane shape decision and membrane processing key technology, it is concluded that form-finding must be considered in membrane self-weight, and the reinforcement membrane and ontology membrane should be at the same direction.

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Biphasic Calcium Phosphate Sphere Graft Combined with a Double-Layer Non-Crosslinked Collagen Membrane Technique for Ridge Preservation: A Randomized Controlled Animal Study

Materials ◽

10.3390/ma13010018 ◽

2019 ◽

Vol 13 (1) ◽

pp. 18 ◽

Cited By ~ 1

Author(s):

Jungwon Lee ◽

Young-Jun Lim ◽

Bongju Kim ◽

Ki-Tae Koo ◽

Yong-Moo Lee

Keyword(s):

Bone Graft ◽

Double Layer ◽

Single Layer ◽

Test Group ◽

Control Group ◽

Collagen Membrane ◽

Ridge Preservation ◽

Graft Material ◽

Membrane Technique ◽

Layer Membrane

The purpose of this study was to compare the histologic and radiologic differences between single- and double-layer collagen membrane techniques in flapless ridge preservation. The mandibular fourth premolar and first molar of four beagle dogs were used in the experiment. Mesial roots of the teeth were extracted and root canal treatment was performed at the distal roots. Ridge preservation was performed at the extraction sites using synthetic bone graft material. A single layer (control group) or double layer (test group) of non-crosslinked collagen membrane was applied following bone graft application. Three months later, the animals were sacrificed and micro-computed tomography (micro-CT) and histomorphometric analyses were conducted. Nonparametric Mann–Whitney test was performed to compare between the control and test groups. The vertical difference between buccal and lingual crests of control and test groups was 1.28 ± 0.41 and 0.53 ± 0.37 mm, respectively (p = 0.026). The mineralized bone area in control and test groups was 31.48% ± 7.41% and 42.25% ± 9.73%, respectively (p = 0.041). Within the limit of this study, ridge preservation using the double-layer membrane technique showed a reduced buccal bone resorption and improved new-bone formation in the ridge compared to that using the single-layer membrane technique.

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Experimental and Theoretical Analysis on the Load Capacity of the Membrane Structure

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.44-47.3092 ◽

2010 ◽

Vol 44-47 ◽

pp. 3092-3095

Author(s):

Ying Ying Zhang ◽

Lu Chen ◽

Qi Lin Zhang

Keyword(s):

Double Layer ◽

Load Capacity ◽

Single Layer ◽

Biaxial Stress ◽

Constitutive Relationship ◽

Material Strength ◽

Ultimate Capacity ◽

Layer Model ◽

Experiment Data ◽

Double Layer Model

In this paper, the representative local part of the membrane roof in 2010 Shanghai EXPO central axis is chosen to carry out the full-size experiment. First, the mechanical properties of PTFE coated fabrics are studied according to the biaxial stress-strain curves under five stress-ratios. The ultimate capacity of single-layer model and double-layer model are got by piling sandbags. The numerical simulations are presented to compare with the experiment data. Results show the material strength, joint strength, and tension protocols agree well with the design. The failure of two models can be considered as material failure. The ultimate capacity of double-layer model is about 1.8 times the single-layer one. The differences between experiment data and numerical simulation are large, because the constitutive relationship used in numerical calculation differs with the practice.

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Comparison of Four Structural Schemes for the Roof Design of Qinyang Stadium

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.438-439.819 ◽

2013 ◽

Vol 438-439 ◽

pp. 819-823 ◽

Cited By ~ 1

Author(s):

Wen Feng Du ◽

Zheng Hao Zhu ◽

Li Ming Zhu

Keyword(s):

Double Layer ◽

Structural Design ◽

Mechanical Performance ◽

Single Layer ◽

Final Decision ◽

Elliptic Paraboloid ◽

Advantages And Disadvantages ◽

Practical Engineering ◽

Roof Design

Basing on the practical engineering of elliptic paraboloid roof structural design in Qinyang Stadium, four structural schemes such as suspend-dome, single-layer latticed shell, double-layer latticed shell and rigid suspend-dome, are calculated and designed respectively. After satisfying the requirements of strength, stiffness and stability, the quantity of steel is compared. The advantages and disadvantages on mechanical performance, construction and cost of four schemes are discussed. Results of comparison provide the accordance for the final decision of structural schemes of Qinyang Stadium and can be referenced by other similar practical engineers.

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Mechanical design of flywheels for energy storage: A review with state-of-the-art developments

Proceedings of the Institution of Mechanical Engineers Part L Journal of Materials Design and Applications ◽

10.1177/1464420717729415 ◽

2017 ◽

Vol 233 (5) ◽

pp. 995-1004 ◽

Cited By ~ 1

Author(s):

Eugenio Dragoni

Keyword(s):

Energy Storage ◽

Large Scale ◽

Mechanical Performance ◽

Mechanical Design ◽

High Strength ◽

Multilayered Structure ◽

Pressure Vessels ◽

Material Strength ◽

Attractive Alternative ◽

Simple Relationship

For years, engineers and designers have capitalized on electrochemical batteries for long-term energy storage, which can only last for a finite number of charge–discharge cycles. More recently, compressed hydrogen is being scrutinized as a large-scale storage medium but this poses the risk of spreading high-pressure vessels with inflammable content. Historically, flywheels have provided an effective way to smooth out speed fluctuations in irregular machines and mechanisms. With advancements in composite materials, magnetic bearings, and mechatronic drives, flywheels have become the subject of extensive research as power storage devices for mobile or fixed installations. Flywheel energy storage systems are considered to be an attractive alternative to electrochemical batteries due to higher stored energy density, higher life term, deterministic state of charge and ecological operation. The mechanical performance of a flywheel can be attributed to three factors: material strength, geometry, and rotational speed. Focusing on the simple relationship between these variables, this paper reviews the literature of flywheel technology and explores the merits of four simple but unconventional flywheel configurations that have not been examined so far. Two geometries assume the use of monolithic isotropic materials two solutions are based on the use of high-strength strips or tapes wound up to form a multilayered structure.

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Dimensional, Mechanical and LCA Characterization of Terrazzo Tiles along with Glass and Construction and Demolition Waste (CDW)

10.21926/rpm.2101006 ◽

2021 ◽

Vol 3 (1) ◽

Author(s):

Paola Stabile ◽

Francesco Radica ◽

Luigi Ranza ◽

Michael R. Carroll ◽

Carlo Santulli ◽

...

Keyword(s):

Double Layer ◽

Mechanical Performance ◽

Raw Materials ◽

Central Italy ◽

Single Layer ◽

Resource Depletion ◽

Construction And Demolition Waste ◽

Demolition Waste ◽

Aesthetic Aspect

In this work, two types of wastes were introduced, namely, glass from municipal waste and Construction and Demolition Waste (CDW). The latter, which was obtained from rubble generated by the seismic events occurred in Central Italy in 2016, was introduced in two configurations, the single-layer and the double-layer of the cement-based Terrazzo tiles. A maximum of 77% of waste introduction was proven to be possible, therefore creating the possibility of obtaining construction products including high quantities of secondary raw materials, coupled with a valuable aesthetic aspect. The tiles represent a novel CDW upcycling application and follow the EU recommendations to improve the circular economy in the building sector. In particular, the products obtained showed dimensional conformity in the specifications and mechanical performance in the case of double-layer tiles as required by the envisaged use in the flooring (EN 13748-1). A life cycle analysis (LCA) clarified the possible advantages in terms of reduced resource depletion (RD) and global warming potential (GWP). The evaluation at the aggregate/glass matrix interface indicated good performance of the tiles, demonstrating the readiness for industrial production and market introduction.

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Study on the Key Technology of Membrane Structure Design in Shanghai Norwegian Pavilion

Sustainable Development of Critical Infrastructure ◽

10.1061/9780784413470.018 ◽

2014 ◽

Author(s):

Hao Song ◽

Zefeng Bi

Keyword(s):

Membrane Structure ◽

Structure Design ◽

Key Technology

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Cracking at the fold in double layer coated paper: the influence of latex and starch composition

TAPPI Journal ◽

10.32964/tj18.2.93 ◽

2019 ◽

Vol 18 (2) ◽

pp. 93-99

Author(s):

SEYYED MOHAMMAD HASHEMI NAJAFI ◽

DOUGLAS BOUSFIELD, ◽

MEHDI TAJVIDI

Keyword(s):

Mechanical Properties ◽

Double Layer ◽

Starch Content ◽

Single Layer ◽

Double Layers ◽

Coated Paper ◽

Coated Papers ◽

Coating Layers ◽

Scanned Images ◽

Packaging Paper

Cracking at the fold of publication and packaging paper grades is a serious problem that can lead to rejection of product. Recent work has revealed some basic mechanisms and the influence of various parameters on the extent of crack area, but no studies are reported using coating layers with known mechanical properties, especially for double-coated systems. In this study, coating layers with different and known mechanical properties were used to characterize crack formation during folding. The coating formulations were applied on two different basis weight papers, and the coated papers were folded. The binder systems in these formulations were different combinations of a styrene-butadiene latex and mixtures of latex and starch for two different pigment volume concentrations (PVC). Both types of papers were coated with single and double layers. The folded area was scanned with a high-resolution scanner while the samples were kept at their folded angle. The scanned images were analyzed within a constant area. The crack areas were reported for different types of papers, binder system and PVC values. As PVC, starch content, and paper basis weight increased, the crack area increased. Double layer coated papers with high PVC and high starch content at the top layer had more cracks in comparison with a single layer coated paper, but when the PVC of the top layer was low, cracking area decreased. No measurable cracking was observed when the top layer was formulated with a 100% latex layer.

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