High‐Strength Flexible Membrane with Rational Pore Architecture as a Selective Radiator for High‐Efficiency Daytime Radiative Cooling

The monitoring of structures is one of the most difficult challenges of engineering in the 21st century. As a result of changes in conditions of use, as well as design errors, many building structures require strengthening. This article presents research on the development of an externally strengthening carbon-fiber textile with a self-sensing option, which is an idea is based on the pattern of resistive strain gauges, where thread is presented in the form of zig-zagging parallel lines. The first laboratory tests showed the system’s high efficiency in the measurement of strains, but also revealed its sensitivity to environmental conditions. This article also presents studies on the influence of temperature and humidity on the measurement, and to separate the two effects, resistance changes were tested on unloaded concrete and wooden samples. The models were then placed in a climatic chamber, and the daily cycle of temperature and humidity changes was simulated. The research results confirmed preliminary observations of resistivity growths along with temperature. This effect is more visible on concrete samples, presumably due to its greater amount of natural humidity. The strain measurement with carbon fibers is very sensitive to temperature changes, and applications of this method in practice require compensation.

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Transverse Deformations and Structural Phenomenon as Indicators of Steel Fibred High-Strength Concrete Nonlinear Behavior

Advances in Materials Science and Engineering ◽

10.1155/2019/9147849 ◽

2019 ◽

Vol 2019 ◽

pp. 1-9 ◽

Cited By ~ 1

Author(s):

Iakov Iskhakov ◽

Yuri Ribakov

Keyword(s):

High Strength Concrete ◽

High Efficiency ◽

Limit State ◽

Nonlinear Behavior ◽

High Strength ◽

Steel Fibers ◽

Ultimate Limit State ◽

Strength Concrete ◽

Brittle Behavior ◽

Ductile Behavior

As known, high-strength compressed concrete elements have brittle behavior, and elastic-plastic deformations do not appear practically up to their ultimate limit state (ULS). This problem is solved in modern practice by adding fibers that allow development of nonlinear deformations in such elements. As a rule, are applied steel fibers that proved high efficiency and contribute ductile behavior of compressed high-strength concrete (HSC) elements as well as the desired effect at long-term loading (for other types of fibers, the second problem is still not enough investigated). However, accurate prediction of the ULS for abovementioned compression elements is still very important and current. With this aim, it is proposed to use transverse deformations in HSC to analyze compression elements' behavior at stages close to ultimate. It is shown that, until the appearance of nonlinear transverse deformations (cracks formation), these deformations are about 5-6 times lower than the longitudinal ones. When cracks appear, the tensile stress-strain relationship in the transverse direction becomes nonlinear. This fact enables to predict that the longitudinal deformations approach the ultimate value. Laboratory tests were carried out on 21 cylindrical HSC specimens with various steel fibers content (0, 20, 30, 40, and 60 kg/m3). As a result, dependences of transverse deformations on longitudinal ones were obtained. These dependences previously proposed by the authors’ concept of the structural phenomenon allow proper estimation of the compressed HSC state up to failure. Good agreement between experimental and theoretical results forms a basis for further development of modern steel fibered HSC theory and first of all nonlinear behavior of HSC.

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Impact Resistance Study of Three-Dimensional Orthogonal Carbon Fibers/BMI Resin Woven Composites

Materials ◽

10.3390/ma13194376 ◽

2020 ◽

Vol 13 (19) ◽

pp. 4376

Author(s):

Yanqi Hu ◽

Zekan He ◽

Haijun Xuan

Keyword(s):

Carbon Fibers ◽

High Efficiency ◽

Laminated Composites ◽

Impact Resistance ◽

Three Dimensional ◽

High Strength ◽

Woven Composites ◽

Failure Behavior ◽

Bismaleimide Resin ◽

Modeling Strategy

Three-dimensional woven composites have been reported to have superior fracture toughness, fatigue life and damage tolerance compared with laminated composites due to through-thickness reinforcement. These properties make them lighter replacements for traditional high-strength metals and laminated composites. This paper will present impact resistance research on three-dimensional orthogonal woven composites consisting of carbon fibers/bismaleimide resin (BMI). A series of impact tests were conducted using the gas gun technique with the impacted target of 150 mm × 150 mm × 8 mm (length × width × thickness) and the cylindrical titanium projectile. The projectile velocity ranged from 180 m/s to 280 m/s, generating different results from rebound to perforation. This paper also presents a multiscale modeling strategy to investigate the damage and failure behavior of three-dimensional woven composites. The microscale and mesoscale are identified to consider the fiber/matrix scale and the tow architecture scale respectively. The macroscale model was effective with homogenized feature. Then a combined meso-macroscale model was developed with the interface definitions for component analysis in the explicit dynamic software LS-DYNA. The presented results showed reliable interface connection and can be used to study localized composites damage at a relatively high efficiency.

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Anisotropic Cellulose Nanofibers/Polyvinyl Alcohol/Graphene Aerogels Fabricated by Directional Freeze-drying as Effective Oil Adsorbents

Polymers ◽

10.3390/polym11040712 ◽

2019 ◽

Vol 11 (4) ◽

pp. 712 ◽

Cited By ~ 9

Author(s):

Lijie Zhou ◽

Shengcheng Zhai ◽

Yiming Chen ◽

Zhaoyang Xu

Keyword(s):

Polyvinyl Alcohol ◽

Freeze Drying ◽

High Efficiency ◽

Cellulose Nanofibers ◽

High Strength ◽

Dip Coating ◽

High Porosity ◽

Water Contact ◽

Water Separation ◽

Composite Aerogel

Under the current situation of frequent oil spills, the development of green and recyclable high-efficiency oil-absorbing aerogel materials has attracted wide attention from researchers. In this study, we report a high-strength, three-dimensional hydrophobic cellulose nanofiber (CNF)/polyvinyl alcohol (PVA)/graphene oxide (GO) composite aerogel with an anisotropic porous structure, which was fabricated by directional freeze-drying technology using anisotropically grown ice crystals as a template, followed by hydrophobic treatment with a simple dip coating process. The prepared composite aerogel presented anisotropic multi-level pore microstructures, low density (17.95 mg/cm3) and high porosity (98.8%), good hydrophobicity (water contact angle of 142°) and great adsorption capacity (oil absorption reaching 96 times its own weight). More importantly, the oriented aerogel had high strength, whose compressive stress at 80% strain reached 0.22 MPa and could bear more than 22,123 times its own weight without deformation. Therefore, the CNF/PVA/GO composite aerogel prepared by a simple and easy-to-operate directional freeze-drying method is a promising absorbent for oil-water separation.

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The Application of New High-Strength Polyester Fiber Flexible Net for the End Coal Mining Through

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.750-752.2141 ◽

2013 ◽

Vol 750-752 ◽

pp. 2141-2144

Author(s):

Qi Tao Duan ◽

Guo Yin Shang ◽

Zhu He Xu ◽

Xi Wen Zhang

Keyword(s):

High Efficiency ◽

Low Cost ◽

Cutting Speed ◽

High Strength ◽

Mining Area ◽

Polyester Fiber ◽

Construction Technology ◽

Metal Mesh ◽

Working Face ◽

Mesh Material

Shendong mining area hanging nets adopted metal mesh material in the traditional through of fully mechanized coal face. Whose defects were the high cost of materials, process cumbersome, great labor intensity and time consuming. Therefore, new high-strength polyester fiber flexible mesh material was introduced. Its main advantages are: light weight, tensile resistance and drag force strong, flame-retardant and anti-static, low cost, simple process, high efficiency, coal cutting speed. The construction technology process in detail were designed which contained flexible network transported, fixed, dropped and raised. The project was implemented in Shigetai Coal at the end of No.12401 mining face. Results show that from working face mounting network to smoothly through with only 40 hours, compared with the traditional metal net can save 44 hours and cost 480000 yuan.

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Multi-Pass Route Planning for Thick Plate of Low Alloy High Strength Steel by Double-Sided Double Arc Welding

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.590.28 ◽

2012 ◽

Vol 590 ◽

pp. 28-34 ◽

Cited By ~ 2

Author(s):

Cheng Dong Yang ◽

H.Y. Huang ◽

H.J. Zhang ◽

Y.X. Chen ◽

San Ben Chen

Keyword(s):

High Strength Steel ◽

Arc Welding ◽

Thick Plate ◽

High Efficiency ◽

Route Planning ◽

High Strength ◽

Welding Parameters ◽

Welding Torch ◽

Welding System

Double-sided double arc welding (DSDAW), a high efficiency method for welding thick plate of low alloy high strength steel which does not require back chipping is used in this paper, research on multi-pass route planning for thick plate of low alloy high strength plate by double-sided double arc welding. Firstly, establish a double-sided double arc welding system that can realize thick plate of low alloy high strength steel double-sided double arc welding by double robots. Then, Propose the multi-pass route planning for thick plate of low alloy high strength steel by double-sided double arc welding by means of misplaced welding. According to the welding parameters and the geometry size of groove, plan the layers, the number of beads and the concrete position of the welding torch for each bead. Finally, the welding experiment has been done to verify the effectiveness of multi-pass route planning. The results of welding experiment are approximately agreement with the multi-pass route planning results. The backing weld can get better appearance in the front and guarantee fusion penetration in the back simultaneously. On the basis of the multi-pass welding route planning, good fusion and leveling interface can be obtained after filler passes.

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Development of NdFeB Permanent Magnet Generator

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.915-916.327 ◽

2014 ◽

Vol 915-916 ◽

pp. 327-330

Author(s):

Rui Min Tao

Keyword(s):

Permanent Magnet ◽

High Efficiency ◽

Permanent Magnet Synchronous Motor ◽

High Strength ◽

Synchronous Generator ◽

Rotor Core ◽

Central Shaft ◽

Ndfeb Permanent Magnet ◽

Pole Surface ◽

Permanent Magnet Generator

Simple permanent magnet synchronous motor has the structure of reliable operation, small size, light weight, high efficiency, flexible shape and size and other characteristics. The pole surface of the rotor core is composed of several small magnet block arrays, spacing, width, height, and the magnet block arrays of magnetic blocks relationship between modulations. This paper introduces a development of NdFeB permanent magnet generator. Rotor structure of high-strength permanent magnet synchronous generator by the central shaft, attached to the core and its outer surface two pairs of circular arc-shaped magnets. The design of structures of the key components is demonstrated and the experimental results show the good performance of the generator.

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