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A simplified method for the determination of vertically loaded pile-soil interface parameters in layered

Jiu-jiang WU,Yan LI,Qian-gong CHENG,Hua WEN,Xin LIANG

《结构与土木工程前沿(英文)》 2016年 第10卷 第1期   页码 103-111 doi: 10.1007/s11709-015-0328-4

摘要: The numerical analysis of pile-soil interaction commonly requires a lot of trial works to determine the interface parameters and the accuracy cannot be ensured normally. Considering this, this paper first conducts a sensitivity analysis to figure out the influence of interface parameters on the bearing behavior of a single pile in sand. Then, a simplified method for the determination of pile-soil interface parameters in layered soil is proposed based on the parameter studies. Finally, a filed loading test is used for the validation of the simplified method, and the calculated results agree well with the monitoring data. In general, the simplified method proposed in this paper works with higher accuracy and consumes less time compared with the traditional trial works, especially on the determinations of interfacial cohesive and interfacial friction angle.

关键词: determination of interface parameters     pile-soil interaction     FLAC3D     sensitivity analysis     layered soil    

Intelligent methods for the process parameter determination of plastic injection molding

Huang GAO, Yun ZHANG, Xundao ZHOU, Dequn LI

《机械工程前沿(英文)》 2018年 第13卷 第1期   页码 85-95 doi: 10.1007/s11465-018-0491-0

摘要:

Injection molding is one of the most widely used material processing methods in producing plastic products with complex geometries and high precision. The determination of process parameters is important in obtaining qualified products and maintaining product quality. This article reviews the recent studies and developments of the intelligent methods applied in the process parameter determination of injection molding. These intelligent methods are classified into three categories: Case-based reasoning methods, expert system-based methods, and data fitting and optimization methods. A framework of process parameter determination is proposed after comprehensive discussions. Finally, the conclusions and future research topics are discussed.

关键词: injection molding     intelligent methods     process parameters     optimization    

Using thermodynamic parameters to study self-healing and interface properties of crumb rubber modified

Dongliang HU, Jianzhong PEI, Rui LI, Jiupeng ZHANG, Yanshun JIA, Zepeng FAN

《结构与土木工程前沿(英文)》 2020年 第14卷 第1期   页码 109-122 doi: 10.1007/s11709-019-0579-6

摘要: The thermodynamic property of asphalt binder is changed by the addition of crumb rubber, which in turn influences the self-healing property as well as the cohesion and adhesion within the asphalt-aggregate system. This study investigated the self-healing and interface properties of crumb rubber modified asphalt (CRMA) using thermodynamic parameters based on the molecular simulation approach. The molecular models of CRMA were built with representative structures of the virgin asphalt and the crumb rubber. The aggregate was represented by SiO and Al O crystals. The self-healing capability was evaluated with the thermodynamic parameter wetting time, work of cohesion and diffusivity. The interface properties were evaluated by characterizing the adhesion capability, the debonding potential and the moisture susceptibility of the asphalt-aggregate interface. The self-healing capability of CRMA is found to decrease as the rubber content increases. The asphalt-Al O interface with higher rubber content has stronger adhesion and moisture stability. But the influence of crumb rubber on the interfacial properties of asphalt-SiO interface has no statistical significance. Comparing with the interfacial properties of the asphalt-SiO interface, the asphalt-Al O interface is found to have a stronger adhesion but a worse moisture susceptibility for its enormous thermodynamic potential for water to displace the asphalt binder.

关键词: crumb rubber modified asphalt     surface free energy     self-healing     interface properties     molecular dynamics simulation    

Determination of the feasible setup parameters of a workpiece to maximize the utilization of a five-axis

Aqeel AHMED, Muhammad WASIF, Anis FATIMA, Liming WANG, Syed Amir IQBAL

《机械工程前沿(英文)》 2021年 第16卷 第2期   页码 298-314 doi: 10.1007/s11465-020-0621-3

摘要: The machining industry must maximize the machine tool utilization for its efficient and effective usage. Determining a feasible workpiece location is one of the significant tasks performed in an iterative way via machining simulations. The maximum utilization of five-axis machine tools depends upon the cutting system’s geometry, the configuration of the machine tool, and the workpiece’s location. In this research, a mathematical model has been developed to determine the workpiece’s feasible location in the five-axis machine tool for avoiding the number of iterations, which are usually performed to eliminate the global collision and axis limit errors. In this research, a generic arrangement of the five-axis machine tool has been selected. The mathematical model of post-processor has been developed by using kinematic modeling methods. The machine tool envelopes have been determined using the post-processor and axial limit. The tooltip reachable workspace is determined by incorporating the post-processor, optimal cutting system length, and machining envelope, thereby further developing an algorithm to determine the feasible workpiece setup parameters accurately. The algorithm’s application has been demonstrated using an example. Finally, the algorithm is validated for feasible workpiece setup parameters in a virtual environment. This research is highly applicable in the industry to eliminate the number of iterations performed for the suitable workpiece setup parameters.

关键词: workpiece setup parameter     five-axis     space utilization     setup parameters     machine tool    

Determination of mechanical parameters for elements in meso-mechanical models of concrete

Xianglin GU, Junyu JIA, Zhuolin WANG, Li HONG, Feng LIN

《结构与土木工程前沿(英文)》 2013年 第7卷 第4期   页码 391-401 doi: 10.1007/s11709-013-0225-7

摘要: The responses of cement mortar specimens of different dimensions under compression and tension were calculated based on the discrete element method with the modified-rigid-body-spring concrete model, in which the mechanical parameters derived from macro-scale material tests were applied directly to the mortar elements. By comparing the calculated results with those predicted by the Carpinteri and Weibull size effects laws, a series of formulas to convert the macro-scale mechanical parameters of mortar and interface to those at the meso-scale were proposed through a fitting analysis. Based on the proposed formulas, numerical simulation of axial compressive and tensile failure processes of concrete and cement mortar materials, respectively were conducted. The calculated results were a good match with the test results.

关键词: concrete     meso-mechanical model     discrete element method     size effect     mechanical parameter    

Effect of interface adhesion factor on the bearing capacity of strip footing placed on cohesive soil

《结构与土木工程前沿(英文)》 2021年 第15卷 第6期   页码 1494-1503 doi: 10.1007/s11709-021-0768-y

摘要: The problem related to bearing capacity of footing either on pure soil or on pure rock mass has been investigated over the years. Currently, no study deals with the bearing capacity of strip footing on a cohesive soil layer overlying rock mass. Therefore, by implementing the lower bound finite element limit analysis in conjunction with the second-order cone programming and the power cone programming, the ultimate bearing capacity of a strip footing located on a cohesive soil overlying rock mass is determined in this study. By considering the different values of interface adhesion factor (αcr) between the cohesive soil and rock mass, the ultimate bearing capacity of strip footing is expressed in terms of influence factor (If) for different values of cohesive soil layer cover ratio (Tcs/B). The failure of cohesive soil is modeled by using Mohr−Coulomb yield criterion, whereas Generalized Hoek−Brown yield criterion is utilized to model the rock mass at failure. The variations ofIf with different magnitudes of αcr are studied by considering the influence of the rock mass strength parameters of beneath rock mass layer. To examine stress distribution at different depths, failure patterns are also plotted.

关键词: bearing capacity     soil-rock interface     Hoek−Brown yield criterion     plasticity     limit analysis    

MGEX轨道与钟差产品的一致性 Article

Peter Steigenberger, Oliver Montenbruck

《工程(英文)》 2020年 第6卷 第8期   页码 898-903 doi: 10.1016/j.eng.2019.12.005

摘要:

国际全球导航卫星系统(GNSS)服务的多GNSS试点项目的分析中心,为全球导航卫星系统,如全球定位系统(GPS)、格洛纳斯卫星导航系统(GLONASS)、伽利略卫星导航系统(Galileo)、北斗卫星导航系统(BeiDou)以及日本区域系统——准天顶卫星导航系统(QZSS)提供轨道和钟差产品。由于改进了太阳辐射压模型和其他更复杂的模型,近年来这些产品的一致性得到了提高。目前,不同分析中心之间GPS轨道一致性为几厘米,GLONASS和Galileo轨道一致性约为1 dm,北斗二号卫星导航系统(BeiDou-2)轨道一致性为几分米,QZSS轨道一致性为数分米。钟差一致性方面,GPS约为2 cm,GLONASS和Galileo约为5 cm,BeiDou-2约为10 cm。在用于精密单点定位的载波相位建模误差方面,各种产品的一致性分别为GPS 2~3 cm、GLONASS 6~14 cm、Galileo 3~10 cm以及BeiDou-2 10~17 cm。

关键词: 全球导航卫星系统     国际GNSS服务     多GNSS试点项目     精密轨道确定     卫星钟差参数    

Experimental verification of the interface wave method to detect interlaminar damage of a metal multilayer

Bing LI,Xu GENG,Tong LU,Lei QIANG,Minghang LI

《机械工程前沿(英文)》 2015年 第10卷 第4期   页码 380-391 doi: 10.1007/s11465-015-0365-7

摘要:

The interface wave traveling along the boundary of two materials has been studied for nearly a century. However, experiments, engineering applications, and interface wave applications to the non-destructive inspection of interlaminar composite have developed slowly. In this research, an experiment that applies Stoneley waves (a type of interfacial wave between two solid half-spaces) is implemented to detect the damage in a multilayer structure. The feasibility of this method is also verified. First, the wave velocity and wave structure of Stoneley waves at a perfectly bonded aluminum-steel interface are obtained by solving the Stoneley wave dispersion equation of two elastic half-spaces. Thereafter, an experiment is conducted to measure the Stoneley wave velocity of an aluminum-steel laminated beam and to locate interlaminar cracks by referring to the Stoneley wave velocity and echo wave time. Results indicate that the location error is less than 2%. Therefore, Stoneley waves show great potential as a non-destructive inspection method of a multilayer structure.

关键词: crack localization     interface waves     Stoneley waves     interlaminar damage     multilayer structure    

Progress in studies of sex determination mechanisms and sex control techniques in

Qian ZHOU,Songlin CHEN

《农业科学与工程前沿(英文)》 2016年 第3卷 第2期   页码 113-123 doi: 10.15302/J-FASE-2016093

摘要: The (half-smooth tongue sole) is a marine flatfish of great commercial value for fisheries and aquaculture in China. It has a female heterogametic sex determination system (ZW/ZZ) and environmental factors can induce sex-reversal of females to phenotypic males, suggesting that it is a promising model for the study of sex determination mechanisms. Additionally, females grow much faster than males and it is feasible to improve the aquaculture production through sex control techniques. This paper reviews the progress in research on sex determination mechanisms research in our laboratory. We have completed whole-genome sequencing and revealed the genome organization and sex chromosome evolution of . A putative male determining gene was identified and DNA methylation was verified as having a crucial role in the sex reversal process. Genetic maps and sex-specific biomarkers have been used in a marker-assisted selection breeding program and for differentiation of the fish sex. Development and improvement of sex control technologies, including artificial gynogenesis and production of breeding fry with high proportion of females, is also reviewed. These research advances have provided insight into the regulation of sex determination and enabled efficient sex management in artificial culturing of .

关键词: Cynoglossus semilaevis     sex determination     sex control technique    

Multi-objective optimization of surface texture for the slipperswash plate interface in EHA pumps

《机械工程前沿(英文)》 2022年 第17卷 第4期 doi: 10.1007/s11465-022-0704-4

摘要: Well-designed surface textures can improve the tribological properties and the efficiency of the electro-hydrostatic actuator (EHA) pump under high-speed and high-pressure conditions. This study proposes a multi-objective optimization model to obtain the arbitrarily surface textures design of the slipper/swash plate interface for improving the mechanical and volumetric efficiency of the EHA pump. The model is composed of the lubrication film model, the component dynamic model considering the spinning motion, and the multi-objective optimization model. In this way, the arbitrary-shaped surface texture with the best comprehensive effect in the EHA pump is achieved and its positive effects in the EHA pump prototype are verified. Experimental results show a reduction in wear and an improvement in mechanical and volumetric efficiency by 1.4% and 0.8%, respectively, with the textured swash plate compared with the untextured one.

关键词: electro-hydrostatic actuator     axial piston pump     slipper/swash plate interface     multi-objective optimization     surface texture    

Thermal analysis of lubricated three-dimensional contact bodies considering interface roughness

《机械工程前沿(英文)》 2022年 第17卷 第2期 doi: 10.1007/s11465-022-0672-8

摘要: Surface roughness and thermal action are of remarkable importance in the lubrication performance of mechanical components, especially in extreme conditions. However, available studies mainly focus on the full-film lubrication conditions without considering temperature rise and real 3D surface roughness due to the complexity of surface topography and temperature characteristics. Moreover, studies on the interfacial thermal behaviors of 3D rough surface lubricated contact in an extended range of working conditions remain limited. In this paper, a deterministic mixed thermal elastohydrodynamic lubrication model considering real 3D surface roughness and thermal effects is proposed. In this model, pressure and temperature are coupled with each other, the computation of elastic deformation is accelerated through the discrete convolution and fast Fourier transform method, the temperature field is calculated with the column sweeping technique, and the semi-system method is introduced to improve convergence and numerical stability under severe conditions. The model is validated by comparing its results with available published numerical and experimental results. The thermal behaviors of the contact interface are studied in a wide range of working conditions. The influences of surface roughness and thermal effect on lubrication performance are revealed. The results show that the proposed model can be used as a powerful analysis tool for lubrication performance and temperature prediction in various heavy-load, high-speed lubricated components over a wide range of lubrication conditions.

关键词: thermal elastohydrodynamic lubrication     surface roughness effect     thermal effect     temperature characteristics     severe conditions    

决定晶体硅太阳电池工作状态的独立参量的确定

丁金磊,程晓舫,翟载腾,查,茆美琴

《中国工程科学》 2007年 第9卷 第4期   页码 94-98

摘要:

从晶体硅太阳电池功率全微分方程出发,结合开路电压和功率随温度、日照变化的实验事实,研究 影响晶体硅太阳电池工作状态的各参量的独立性。从数学上确定出其独立变量为日照强度、电池温度和负载, 并得出了串联内阻是温度的函数的结论。串联内阻的实验数据验证了理论分析结果的正确性。

关键词: 晶体硅太阳电池     功率全微分     参量独立性     串联内阻    

Rapid method for on-site determination of phenolic contaminants in water using a disposable biosensor

Yuanting LI, Dawei LI, Wei SONG, Meng LI, Jie ZOU, Yitao LONG

《环境科学与工程前沿(英文)》 2012年 第6卷 第6期   页码 831-838 doi: 10.1007/s11783-012-0393-z

摘要: A disposable biosensor was fabricated using single-walled carbon nanotubes, gold nanoparticles and tyrosinase (SWCNTs-AuNPs-Tyr) modified screen-printed electrodes. The prepared biosensor was applied to the rapid determination of phenolic contaminants within 15 minutes. The SWCNTs-AuNPs-Tyr bionanocomposite sensing layer was characterized with scanning electron microscopy, electrochemical impedance spectroscopy and cyclic voltammetry methods. The characterization results revealed that SWCNTs could lead to a high loading of tyrosinase (Tyr) with the large surface area and the porous morphology, while AuNPs could retain the bioactivity of Tyr and enhance the sensitivity. The detection conditions, including working potential, pH of supporting electrolyte and the amount of Tyr were optimumed. As an example, the biosensor for catechol determination displayed a linear range of 8.0 × 10 to 2.0 × 10 mol·L with a detection limit of 4.5 × 10 mol·L (S/ = 3). This method has a rapid response time within 10 s, and shows excellent repeatability and stability. Moreover, the resulting biosensor could be disposable, low-cost, reliable and easy to carry. This kind of new Tyr biosensor provides great potential for rapid, on-site and cost-effective analysis of phenolic contaminants in environmental water samples.

关键词: on-site determination     tyrosinase biosensor     phenolic contaminants     single-walled carbon nanotubes     gold nanoparticles     screen-printed electrodes    

Winner determination problem with loss-averse buyers in reverse auctions

Xiaohu QIAN, Min HUANG, Yangyang YU, Xingwei WANG

《工程管理前沿(英文)》 2017年 第4卷 第2期   页码 212-220 doi: 10.15302/J-FEM-2017019

摘要: Reverse auctions have been widely adopted for purchasing goods and services. This paper considers a novel winner determination problem in a multiple-object reverse auction in which the buyer involves loss-averse behavior due to uncertain attributes. A corresponding winner determination model based on cumulative prospect theory is proposed. Due to the NP-hard characteristic, a loaded route strategy is proposed to ensure the feasibility of the model. Then, an improved ant colony algorithm that consists of a dynamic transition strategy and a Max-Min pheromone strategy is designed. Numerical experiments are conducted to illustrate the effectiveness of the proposed model and algorithm. We find that under the loaded route strategy, the improved ant colony algorithm performs better than the basic ant colony algorithm. In addition, the proposed model can effectively characterize the buyer’s loss-averse behavior.

关键词: reverse auction     loss aversion     winner determination     improved ant colony algorithm    

Tribological mechanism of carbon group nanofluids on grinding interface under minimum quantity lubrication

《机械工程前沿(英文)》 2023年 第18卷 第1期 doi: 10.1007/s11465-022-0733-z

摘要: Carbon group nanofluids can further improve the friction-reducing and anti-wear properties of minimum quantity lubrication (MQL). However, the formation mechanism of lubrication films generated by carbon group nanofluids on MQL grinding interfaces is not fully revealed due to lack of sufficient evidence. Here, molecular dynamic simulations for the abrasive grain/workpiece interface were conducted under nanofluid MQL, MQL, and dry grinding conditions. Three kinds of carbon group nanoparticles, i.e., nanodiamond (ND), carbon nanotube (CNT), and graphene nanosheet (GN), were taken as representative specimens. The [BMIM]BF4 ionic liquid was used as base fluid. The materials used as workpiece and abrasive grain were the single-crystal Ni–Fe–Cr series of Ni-based alloy and single-crystal cubic boron nitride (CBN), respectively. Tangential grinding force was used to evaluate the lubrication performance under the grinding conditions. The abrasive grain/workpiece contact states under the different grinding conditions were compared to reveal the formation mechanism of the lubrication film. Investigations showed the formation of a boundary lubrication film on the abrasive grain/workpiece interface under the MQL condition, with the ionic liquid molecules absorbing in the groove-like fractures on the grain wear’s flat face. The boundary lubrication film underwent a friction-reducing effect by reducing the abrasive grain/workpiece contact area. Under the nanofluid MQL condition, the carbon group nanoparticles further enhanced the tribological performance of the MQL technique that had benefited from their corresponding tribological behaviors on the abrasive grain/workpiece interface. The behaviors involved the rolling effect of ND, the rolling and sliding effects of CNT, and the interlayer shear effect of GN. Compared with the findings under the MQL condition, the tangential grinding forces could be further reduced by 8.5%, 12.0%, and 14.1% under the diamond, CNT, and graphene nanofluid MQL conditions, respectively.

关键词: grinding     minimum quantity lubrication     carbon group nanofluid     tribological mechanism    

标题 作者 时间 类型 操作

A simplified method for the determination of vertically loaded pile-soil interface parameters in layered

Jiu-jiang WU,Yan LI,Qian-gong CHENG,Hua WEN,Xin LIANG

期刊论文

Intelligent methods for the process parameter determination of plastic injection molding

Huang GAO, Yun ZHANG, Xundao ZHOU, Dequn LI

期刊论文

Using thermodynamic parameters to study self-healing and interface properties of crumb rubber modified

Dongliang HU, Jianzhong PEI, Rui LI, Jiupeng ZHANG, Yanshun JIA, Zepeng FAN

期刊论文

Determination of the feasible setup parameters of a workpiece to maximize the utilization of a five-axis

Aqeel AHMED, Muhammad WASIF, Anis FATIMA, Liming WANG, Syed Amir IQBAL

期刊论文

Determination of mechanical parameters for elements in meso-mechanical models of concrete

Xianglin GU, Junyu JIA, Zhuolin WANG, Li HONG, Feng LIN

期刊论文

Effect of interface adhesion factor on the bearing capacity of strip footing placed on cohesive soil

期刊论文

MGEX轨道与钟差产品的一致性

Peter Steigenberger, Oliver Montenbruck

期刊论文

Experimental verification of the interface wave method to detect interlaminar damage of a metal multilayer

Bing LI,Xu GENG,Tong LU,Lei QIANG,Minghang LI

期刊论文

Progress in studies of sex determination mechanisms and sex control techniques in

Qian ZHOU,Songlin CHEN

期刊论文

Multi-objective optimization of surface texture for the slipperswash plate interface in EHA pumps

期刊论文

Thermal analysis of lubricated three-dimensional contact bodies considering interface roughness

期刊论文

决定晶体硅太阳电池工作状态的独立参量的确定

丁金磊,程晓舫,翟载腾,查,茆美琴

期刊论文

Rapid method for on-site determination of phenolic contaminants in water using a disposable biosensor

Yuanting LI, Dawei LI, Wei SONG, Meng LI, Jie ZOU, Yitao LONG

期刊论文

Winner determination problem with loss-averse buyers in reverse auctions

Xiaohu QIAN, Min HUANG, Yangyang YU, Xingwei WANG

期刊论文

Tribological mechanism of carbon group nanofluids on grinding interface under minimum quantity lubrication

期刊论文