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Soft curvature sensors for measuring the rotational angles of mechanical fingers

Haixiao LIU, Li LI, Zhikang OUYANG, Wei SUN

《机械工程前沿(英文)》 2020年 第15卷 第4期   页码 610-621 doi: 10.1007/s11465-020-0596-0

摘要: The design, fabrication, and testing of soft sensors that measure elastomer curvature and mechanical finger bending are described in this study. The base of the soft sensors is polydimethylsiloxane (PDMS), which is a translucent elastomer. The main body of the soft sensors consists of three layers of silicone rubber plate, and the sensing element is a microchannel filled with gallium-indium-tin (Ga-In-Sn) alloy, which is embedded in the elastomer. First, the working principle of soft sensors is investigated, and their structure is designed. Second, the relationship between curvature and resistance is determined. Third, several sensors with different specifications are built in accordance with the structural design. Experiments show that the sensors exhibit high accuracy when the curvature changes within a certain range. Lastly, the soft sensors are applied to the measurement of mechanical finger bending. Experiments show that soft curvature sensors can effectively reflect mechanical finger bending and can be used to measure the bending of mechanical fingers with high sensitivity within a certain working range.

关键词: soft sensor     Ga-In-Sn alloy     strain sensing     curvature sensing     mechanical finger bending    

采用分布式光纤传感技术的土坝模型渗漏监测分析

朱萍玉,蒋桂林,冷元宝

《中国工程科学》 2011年 第13卷 第3期   页码 82-85

摘要:

建立了采用分布式光纤传感技术的模拟堤坝渗漏监测系统,用来人工模拟土坝渗漏,并得到该种情况下测试光纤长度上的应变图,验证了采用分布式光纤传感技术监测土坝的可行性;运用ANSYS软件建立与试验模型相对应的有限元分析模型,通过选择合适单元,简化边界条件,对一定的工况进行加载分析,得出载荷与应变的关系,以及载荷与塌陷土层重量的关系。文中方法和结论有助于进一步定量研究土坝渗漏大小程度和光纤传感器的合适埋设深度。

关键词: 光纤传感技术     土坝模型     监测     应变     ANSYS    

Concepts and implementation of strain-based criteria in design codes for steel structures

Reidar BJORHOVDE

《结构与土木工程前沿(英文)》 2012年 第6卷 第3期   页码 210-216 doi: 10.1007/s11709-012-0165-7

摘要: A uniaxial tension test is commonly used to determine the mechanical properties of steel, but it has no meaning for the response of the material in a structure. The test was developed as a consensus solution by producers, fabricators, designers and code writers, to have a standard by which similar materials could be compared to a common base. It does not represent the actual behavior of the steel in a structure, and was never intended to do so. To study the true behavior of the structure and how the material responds it would be better to determine the strains and deformations that will take place during actual service condition. Such characteristics reflect the real behavior, whether in the elastic or inelastic range. If stresses or forces are needed, these are easily determined by the value of the strain and the relevant material modulus, along with the type of cross section, whether elastic or inelastic. The paper addresses the properties of a range of structural steels, how these are incorporated into design standards and how the standards define deformation characteristics and demands for bolted and welded connections.

关键词: steel     stress-strain characteristics     tension test     strain design     actual behavior     improved design codes    

Novel sensing techniques for full-scale testing of civil structures

Kaoshan DAI, Zhenhua HUANG

《结构与土木工程前沿(英文)》 2012年 第6卷 第3期   页码 240-256 doi: 10.1007/s11709-012-0172-8

摘要: Performing full-scale structural testing is an important methodology for researchers and engineers in the civil engineering industry. Full scale testing helps the researchers understand civil infrastructures’ loading scenarios, behaviors, and health conditions. It helps the engineers verify, polish, and simplify the structural design and analysis theories. To conduct a full-scale structural testing, sensors are used for data acquisitions. To help structural researchers and engineers get familiar with sensing technologies and select the most effective sensors, this study reviewed and categorized new sensing techniques for full-scale structural testing applications. The researchers of this study categorized sensors used for civil-infrastructure testing into traditional contact sensors and remote sensors based upon their application methodologies, and into cabled sensors and wireless sensors based upon their data communication strategies. The detailed descriptions of wireless sensors and remote sensing techniques and their on-site full-scale applications are presented.

关键词: sensing technique     full-scale testing     wireless sensor     remote sensing     LiDAR     laser vibrometer    

Full-field dynamic strain reconstruction of an aero-engine blade from limited displacement responses

《机械工程前沿(英文)》 2023年 第18卷 第1期 doi: 10.1007/s11465-022-0731-1

摘要: Blade strain distribution and its change with time are crucial for reliability analysis and residual life evaluation in blade vibration tests. Traditional strain measurements are achieved by strain gauges (SGs) in a contact manner at discrete positions on the blades. This study proposes a method of full-field and real-time strain reconstruction of an aero-engine blade based on limited displacement responses. Limited optical measured displacement responses are utilized to reconstruct the full-field strain. The full-field strain distribution is in-time visualized. A displacement-to-strain transformation matrix is derived on the basis of the blade mode shapes in the modal coordinate. The proposed method is validated on an aero-engine blade in numerical and experimental cases. Three discrete vibrational displacement responses measured by laser triangulation sensors are used to reconstruct the full-field strain over the whole operating time. The reconstructed strain responses are compared with the results measured by SGs and numerical simulation. The high consistency between the reconstructed and measured results demonstrates the accurate strain reconstructed by the method. This paper provides a low-cost, real-time, and visualized measurement of blade full-field dynamic strain using displacement response, where the traditional SGs would fail.

关键词: aero-engine blade     displacement response     dynamic strain reconstruction     mode shape     strain gauge    

An Ultracompact Spoof Surface Plasmon Sensing System for Adaptive and Accurate Detection of Gas Using

Xuanru Zhang,Jia Wen Zhu,Tie Jun Cui,

《工程(英文)》 doi: 10.1016/j.eng.2023.05.013

摘要: Resonantly enhanced dielectric sensing has superior sensitivity and accuracy because the signal is measured from relative resonance shifts that are immune to signal fluctuations. For applications in the Internet of Things (IoT), accurate detection of resonance frequency shifts using a compact circuit is in high demand. We proposed an ultracompact integrated sensing system that merges a spoof surface plasmon resonance sensor with signal detection, processing, and wireless communication. A software-defined scheme was developed to track the resonance shift, which minimized the hardware circuit and made the detection adaptive to the target resonance. A microwave spoof surface plasmon resonator was designed to enhance sensitivity and resonance intensity. The integrated sensing system was constructed on a printed circuit board with dimensions of 1.8 cm × 1.2 cm and connected to a smartphone wirelessly through Bluetooth, working in both frequency scanning mode and resonance tracking mode and achieving a signal-to-noise ratio of 69 dB in acetone vapor sensing. This study provides an ultracompact, accurate, adaptive, sensitive, and wireless solution for resonant sensors in the IoT.

关键词: Spoof surface plasmons     Internet of Things     Integrated sensing     Resonance tracking     Microwave sensing    

Strain and process engineering toward continuous industrial fermentation

《化学科学与工程前沿(英文)》 2023年 第17卷 第10期   页码 1336-1353 doi: 10.1007/s11705-022-2284-6

摘要: Most current biotechnology industries are based on batch or fed-batch fermentation processes, which often show low productivity and high production costs compared to chemical processes. To increase the economic competitiveness of biological processes, continuous fermentation technologies are being developed that offer significant advantages in comparison with batch/fed-batch fermentation processes, including: (1) removal of potential substrates and product inhibition, (2) prolonging the microbial exponential growth phase and enhancing productivity, and (3) avoiding repeated fermentation preparation and lowering operation and installation costs. However, several key challenges should be addressed for the industrial application of continuous fermentation processes, including (1) contamination of the fermentation system, (2) degeneration of strains, and (3) relatively low product titer. In this study, we reviewed and discussed metabolic engineering and synthetic biology strategies to address these issues.

关键词: continuous fermentation     productivity     contamination     strain degeneration     metabolic engineering    

Behavior of steel fiber–reinforced high-strength concrete at medium strain rate

Chujie JIAO, Wei SUN, Shi HUAN, Guoping JIANG

《结构与土木工程前沿(英文)》 2009年 第3卷 第2期   页码 131-136 doi: 10.1007/s11709-009-0027-0

摘要: Impact compression experiments for the steel fiber–reinforced high-strength concrete (SFRHSC) at medium strain rate were conducted using the split Hopkinson press bar (SHPB) testing method. The volume fractions of steel fibers of SFRHSC were between 0 and 3%. The experimental results showed that, when the strain rate increased from threshold value to 90 s , the maximum stress of SFRHSC increased about 30%, the elastic modulus of SFRHSC increased about 50%, and the increase in the peak strain of SFRHSC was 2-3 times of that in the matrix specimen. The strength and toughness of the matrix were improved remarkably because of the superposition effect of the aggregate high-strength matrix and steel fiber high-strength matrix. As a result, under impact loading, cracks developed in the SFRHSC specimen, but the overall shape of the specimen remained virtually unchanged. However, under similar impact loading, the matrix specimens were almost broken into small pieces.

关键词: steel fiber–reinforced high-strength concrete (SFRHSC)     high strain rates     split Hopkinson press bar (SHPB)     strain rate hardening effects    

Vibration analysis of nano-structure multilayered graphene sheets using modified strain gradient theory

Amir ALLAHBAKHSHI,Masih ALLAHBAKHSHI

《机械工程前沿(英文)》 2015年 第10卷 第2期   页码 187-197 doi: 10.1007/s11465-015-0339-9

摘要:

In this paper, for the first time, the modified strain gradient theory is used as a new size-dependent Kirchhoff micro-plate model to study the effect of interlayer van der Waals (vdW) force for the vibration analysis of multilayered graphene sheets (MLGSs). The model contains three material length scale parameters, which may effectively capture the size effect. The model can also degenerate into the modified couple stress plate model or the classical plate model, if two or all of the material length scale parameters are taken to be zero. After obtaining the governing equations based on modified strain gradient theory via principle of minimum potential energy, as only infinitesimal vibration is considered, the net pressure due to the vdW interaction is assumed to be linearly proportional to the deflection between two layers. To solve the governing equation subjected to the boundary conditions, the Fourier series is assumed for w=w(xy). To show the accuracy of the formulations, present results in specific cases are compared with available results in literature and a good agreement can be seen. The results indicate that the present model can predict prominent natural frequency with the reduction of structural size, especially when the plate thickness is on the same order of the material length scale parameter.

关键词: graphene     van der Waals (vdW) force     modi- fied strain gradient elasticity theory     size effect parameter    

Quorum sensing regulation methods and their effects on biofilm in biological waste treatment systems:

《环境科学与工程前沿(英文)》 2022年 第16卷 第7期 doi: 10.1007/s11783-021-1495-2

摘要:

• Quorum sensing enhancement and inhibition methods are summarized.

关键词: Quorum sensing     Biological waste treatment     Biofilm formation    

Plasma-enabled sensing of urea and related amides on polyaniline

Harinarayanan Puliyalil,Petr Slobodian,Michal Sedlacik,Ruhan Benlikaya,Pavel Riha,Kostya (Ken) Ostrikov,Uroš Cvelbar

《化学科学与工程前沿(英文)》 2016年 第10卷 第2期   页码 265-272 doi: 10.1007/s11705-016-1570-6

摘要: The atmospheric pressure plasma jet (APPJ) was used to enhance the sensitivity of industrially important polyaniline (PANI) for detection of organic vapors from amides. The gas sensing mechanism of PANI is operating on the basis of reversible protonation or deprotonation, whereas the driving force to improve the sensitivity after plasma modifications is unknown. Herein we manage to solve this problem and investigate the sensing mechanism of atmospheric plasma treated PANI for vapor detection of amides using urea as a model. The results from various analytical techniques indicate that the plausible mechanism responsible for the improved sensitivity after plasma treatment is operating through a cyclic transition state formed between the functional groups introduced by plasma treatment and urea. This transition state improved the sensitivity of PANI towards 15 ppm of urea by a factor of 2.4 times compared to the non-treated PANI. This plasma treated PANI is promising for the improvement of the sensitivity and selectivity towards other toxic and carcinogenic amide analytes for gas sensing applications such as improving material processing and controlling food quality.

关键词: gas sensing     urea     PANI     amides     plasma    

FEM-based strain analysis study for multilayer sheet forming process

Rongjing ZHANG,Lihui LANG,Rizwan ZAFAR

《机械工程前沿(英文)》 2015年 第10卷 第4期   页码 373-379 doi: 10.1007/s11465-015-0371-9

摘要:

Fiber metal laminates have many advantages over traditional laminates (e.g., any type of fiber and resin material can be placed anywhere between the metallic layers without risk of failure of the composite fabric sheets). Furthermore, the process requirements to strictly control the temperature and punch force in fiber metal laminates are also less stringent than those in traditional laminates. To further explore the novel method, this study conducts a finite element method-based (FEM-based) strain analysis on multilayer blanks by using the 3A method. Different forming modes such as wrinkling and fracture are discussed by using experimental and numerical studies. Hydroforming is used for multilayer forming. The Barlat 2000 yield criteria and DYNAFORM/LS-DYNA are used for the simulations. Optimal process parameters are determined on the basis of fixed die-binder gap and variable cavity pressure. The results of this study will enhance the knowledge on the mechanics of multilayer structures formed by using the 3A method and expand its commercial applications.

关键词: finite element method (FEM)     strain analysis     multilayer sheet forming    

Stress-strain relationship of concrete in freeze-thaw environment

ZOU Chaoying, ZHAO Juan, LIANG Feng

《结构与土木工程前沿(英文)》 2008年 第2卷 第2期   页码 184-188 doi: 10.1007/s11709-008-0029-3

摘要: Adopting the ASTM C666 quick freeze-thaw method, freeze-thaw tests with the number of freeze-thaw cycles being 0, 100, 150, 200, 250, and 300, were carried out on eighteen concrete prism specimens, the frost-resistant level of which, reaches D300 grade. The internal micro-structures of these specimens were observed by means of scanning electron microscopy (SEM) in order to detect damages caused by the freeze-thaw action. Afterwards these frozen-thawed specimens were tested on monotonic axial load; stress-strain testing curves after the freeze-thaw action were obtained. The testing results show that with the increasing time of freeze-thaw cycles, both the internal micro-structures and the basic mechanical parameters, including the ultimate bearing capacity, the Poisson ratio and the modulus of elasticity, degenerate in various degrees. Finally, stress-strain theoretical curvilinear equations and correlated parameters relating to the loss of relative dynamic modulus of elasticity were proposed. These results provide great reference for further research on the behavior and the calculation model of concrete structures in a freeze-thaw environment.

关键词: stress-strain theoretical     freeze-thaw     capacity     reference     eighteen concrete    

Fictitious soil pile model for dynamic analysis of pipe piles under high-strain conditions

《结构与土木工程前沿(英文)》   页码 915-934 doi: 10.1007/s11709-023-0907-8

摘要: A fictitious soil pile (FSP) model is developed to simulate the behavior of pipe piles with soil plugs undergoing high-strain dynamic impact loading. The developed model simulates the base soil with a fictitious hollow pile fully filled with a soil plug extending at a cone angle from the pile toe to the bedrock. The friction on the outside and inside of the pile walls is distinguished using different shaft models, and the propagation of stress waves in the base soil and soil plug is considered. The motions of the pile−soil system are solved by discretizing them into spring-mass model based on the finite difference method. Comparisons of the predictions of the proposed model and conventional numerical models, as well as measurements for pipe piles in field tests subjected to impact loading, validate the accuracy of the proposed model. A parametric analysis is conducted to illustrate the influence of the model parameters on the pile dynamic response. Finally, the effective length of the FSP is proposed to approximate the affected soil zone below the pipe pile toe, and some guidance is provided for the selection of the model parameters.

关键词: fictitious soil pile     soil plug     pipe piles     high-strain dynamic analysis     one-dimensional wave theory     pile dynamics    

Influence of freeze–thaw damage gradient on stress–strain relationship of stressed concrete

《结构与土木工程前沿(英文)》   页码 1326-1340 doi: 10.1007/s11709-023-0014-x

摘要: Influence of freeze–thaw damage gradient on stress–strain relationship of stressed concrete

关键词: strain relationship concrete    

标题 作者 时间 类型 操作

Soft curvature sensors for measuring the rotational angles of mechanical fingers

Haixiao LIU, Li LI, Zhikang OUYANG, Wei SUN

期刊论文

采用分布式光纤传感技术的土坝模型渗漏监测分析

朱萍玉,蒋桂林,冷元宝

期刊论文

Concepts and implementation of strain-based criteria in design codes for steel structures

Reidar BJORHOVDE

期刊论文

Novel sensing techniques for full-scale testing of civil structures

Kaoshan DAI, Zhenhua HUANG

期刊论文

Full-field dynamic strain reconstruction of an aero-engine blade from limited displacement responses

期刊论文

An Ultracompact Spoof Surface Plasmon Sensing System for Adaptive and Accurate Detection of Gas Using

Xuanru Zhang,Jia Wen Zhu,Tie Jun Cui,

期刊论文

Strain and process engineering toward continuous industrial fermentation

期刊论文

Behavior of steel fiber–reinforced high-strength concrete at medium strain rate

Chujie JIAO, Wei SUN, Shi HUAN, Guoping JIANG

期刊论文

Vibration analysis of nano-structure multilayered graphene sheets using modified strain gradient theory

Amir ALLAHBAKHSHI,Masih ALLAHBAKHSHI

期刊论文

Quorum sensing regulation methods and their effects on biofilm in biological waste treatment systems:

期刊论文

Plasma-enabled sensing of urea and related amides on polyaniline

Harinarayanan Puliyalil,Petr Slobodian,Michal Sedlacik,Ruhan Benlikaya,Pavel Riha,Kostya (Ken) Ostrikov,Uroš Cvelbar

期刊论文

FEM-based strain analysis study for multilayer sheet forming process

Rongjing ZHANG,Lihui LANG,Rizwan ZAFAR

期刊论文

Stress-strain relationship of concrete in freeze-thaw environment

ZOU Chaoying, ZHAO Juan, LIANG Feng

期刊论文

Fictitious soil pile model for dynamic analysis of pipe piles under high-strain conditions

期刊论文

Influence of freeze–thaw damage gradient on stress–strain relationship of stressed concrete

期刊论文