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      • KCI등재

        Winding strategy of driving cable based on dynamic analysis of deployment for deployable antennas

        Yiqun Zhang,Dongwu Yang,Zihan Sun,Na Li,Jianghua Du 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.11

        An optimization method for the winding strategy of the driving cable is proposed based on a dynamic analysis of the AstroMesh antenna deployment. First, considering the effects of the cable net and friction, the driving force for deployment is deduced according to energy conservation. Thereafter, an optimization model is constructed, with the objective of minimum deployment driving power, using design variables consisting of control parameters of the winding length curve of the driving cable; this curve is described by the Bezier curve. Moreover, corresponding to the winding process of the driving cable before and after optimization, deployment experiments for a 2-m aperture deployable antenna prototype are conducted. Finally, the validity and rationality of the optimization method are verified by comparing the simulation and experimental results.

      • KCI등재

        A novel numerical approach for workspace determination of parallel mechanisms

        Yiqun Zhou,Junchuan Niu,Zhihui Liu,Fuliang Zhang 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.6

        In this paper, a novel numerical approach is proposed for workspace determination of parallel mechanisms. Compared with the classicalnumerical approaches, this presented approach discretizes both location and orientation of the mechanism simultaneously, not onlyone of the two. This technique makes the presented numerical approach applicable in determining almost all types of workspaces, whiletraditional numerical approaches are only applicable in determining the constant orientation workspace and orientation workspace. Thepresented approach and its steps to determine the inclusive orientation workspace and total orientation workspace are described in detail. A lower-mobility parallel mechanism and a six-degrees-of-freedom Stewart platform are set as examples, the workspaces of thesemechanisms are estimated and visualized by the proposed numerical approach. Furthermore, the efficiency of the presented approach isdiscussed. The examples show that the presented approach is applicable in determining the inclusive orientation workspace and totalorientation workspace of parallel mechanisms with high efficiency.

      • SCIESCOPUSKCI등재

        Effects of α-Galactosidase Supplementation on Performance and Energy Metabolism for Broilers Fed Corn-non-dehulled Soybean Meal Diets

        Zhang, Bo,Cao, Yunhe,Chen, Yiqun,Li, Yihang,Qiao, Shiyan,Ma, Yongxi Asian Australasian Association of Animal Productio 2010 Animal Bioscience Vol.23 No.10

        To study the effects of ${\alpha}$-galactosidase (${\alpha}$-Gal) supplementation on performance and energy metabolism, 216 Arbor Acres male broilers were placed in 36 cages of 6 birds each and allotted to 4 diets for 42 d, with 0-21 d as starter period and 22-42 d as grower period. The 4 diets were based on corn non-dehulled soybean meal in a $2{\times}2$ factorial arrangement, with 2 levels of ${\alpha}$-Gal (0 vs. 60 U/kg feed) and 2 levels of ME (normal metabolizable energy (NME) and low metabolizable energy (LME)). Bird performance was obtained at 21 and 42 d of age with samples of feces collected for nutrient digestibility from 19-21 d and 40-42 d. At 21 and 42 d, 1 bird from 6 cages of each treatment was killed to determine liver weight, intestinal pH and chyme viscosity. With the addition of ${\alpha}$-Gal the 42 d body weight (BW) and 0-42 d average daily gain (ADG) were significantly improved (p<0.05). Average daily feed intake (ADFI) of birds fed the LME diet was significantly increased compared to those fed the NME diet during starter (p<0.01) and grower (p<0.05) periods and overall (p<0.01). There was an interaction of ${\alpha}-Gal{\times}ME$ on 0-21 d ADFI (p<0.01). Supplementation of ${\alpha}$-Gal significantly improved (p<0.01) feed efficiency during the grower period and overall. Feed efficiency of birds fed the LME diet was significantly decreased (p<0.05) compared to those fed the NME diet during the starter period and overall. With the addition of ${\alpha}$-Gal apparent metabolizable energy (AME) was improved (p<0.01) by 2.1% and 1.8% during starter and grower periods, respectively. There was a main effect (p<0.05) of ${\alpha}$-Gal on the digestion of neutral detergent fiber (NDF) during the starter period and crude protein (CP), NDF and acid detergent fiber (ADF) during the grower period. With the addition of ${\alpha}$-Gal, the relative weight of liver was reduced (p<0.01) during the two phases. The duodenal and jejunal pH were significantly decreased (p<0.01) with the supplementation of ${\alpha}$at the two phases. ${\alpha}$-Gal addition reduced (p<0.01) chyme viscosity of the ileum during the starter and grower periods. Overall, ${\alpha}$-Gal showed a major effect on nutrient efficiency, improved ADG and feed efficiency, whereas LME decreased feed efficiency. The incorporation of ${\alpha}$-Gal into a LME diet could at least partially offset ME deficiency of non-dehulled soybean meal.

      • KCI등재

        Global sensitivity analysis for cablenetwork antennas by Kriging models with a sensitivity-based accuracy indicator

        Naigang Hu,Yiqun Zhang,Guigeng Yang,Dongwu Yang 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.8

        Various uncertainties existing in the manufacturing process, such as imperfect cable lengths and uncertain boundary node locations, will unavoidably deteriorate the shape precision of cable-network antennas. In this paper, an adaptive Kriging-based method is developed to investigate the global sensitivity of uncertain parameters and discover the influential factors. Existing strategies in literature usually use relative error of function values to measure the metamodel accuracy and then to determine when the sequential sampling process should be stopped. However, these indicators are mostly developed based on function values, not the sensitivity indices. Therefore, it is difficult to determine how small the indicators should be for efficiently defining an accurate metamodel for sensitivity analysis. In this paper, a straightforward sensitivity-based indicator is developed to measure the metamodel accuracy, which is defined as the weighted average of absolute errors of sensitivity values between two successive iterations. A use-controlled threshold, combined with the new indicator, can provide an automatic stopping criterion for the adaptive metamodel building process. The proposed method can provide a uniform framework to detect the convergence status effectively for problems with different uncertainties and dimensions. A numerical example and two cable-network antenna examples considering different manufacturing uncertainties are illustrated to validate the new method.

      • KCI등재

        Structural evaluation of a foldable cable-strut structure for kinematic roofs

        Jianguo Cai,Qian Zhang,Yiqun Zhang,Daniel Sang-hoon Lee,Jianfeng Zhao 국제구조공학회 2018 Steel and Composite Structures, An International J Vol.29 No.5

        The rapidly decreasing natural resources and the global variation of the climate push us to find intelligent and efficient structural systems to provide more people with fewer resources. This paper proposed a kinematic cable-strut system to realize sustainable structures in responding to changing environmental conditions. At first, the concept of the kinematic system based on crystal-cell pyramid (CP) cable-strut unit was given. Then the deployment of the structure was studied experimentally. After that, the static behaviors in the fully deployed state under the symmetric and asymmetric load cases were investigated. Moreover, the effects of thermal loading and the initial prestress distribution were also discussed. Comparative studies between the proposed structure and other deployable cable-strut system under three times of design load cases were carried out. Finally, the robustness of the system was studied by removal of one passive cable at one time.

      • KCI등재

        Path Tracking Control of Skid-steered Mobile Robot on the Slope Based on Fuzzy System and Model Predictive Control

        Xiao Yue,Jiankui Chen,Yiqun Li,Rong Zou,Zhihao Sun,Xiaochuan Cao,Song Zhang 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.4

        Skid-steered mobile robots are often used in outdoor exploration due to their robust mechanical structure and high maneuverability. When they track reference path on a slope with boundaries, ensuring the tracking accuracy and stability of the skid-steered mobile robot is the major target. However, the gravity makes the relationship between wheels and ground more complex on the slope, and variational slope angle also makes it difficult for tracking control. The common control methods focus on plane motion, where only the plane forces are taken into account and the gravity is normally ignored. It may lead to some performance limitations such as the accuracy of motion on a slope. To address these problems, a model predictive control strategy combined with a fuzzy system is proposed in this paper, which has considered the dynamics of the body and wheels on the slope. We improved the two dimensional kinematics and dynamics model of the robot, which makes the three dimensional motion control more accurate. And the control method allows the robot to adapt to slopes with different angles and to make the path tracking stable to curvature mutation. Both experiment and simulation results demonstrate the effectiveness and superiority of the proposed model and method.

      • KCI등재

        Experimental and Numerical Analysis of the Ribbed Reinforced Concrete Fracture Behavior Based on the Mesoscale FE Model

        Zhanliang Wang,Wei Zhang,Yiqun Huang 한국콘크리트학회 2023 International Journal of Concrete Structures and M Vol.17 No.5

        This study presented a meso-model for the fracture analysis of the reinforced concrete (RC) structure. A modeling method of RC meso-structure was proposed, and the rebars were allowed to separate from the concrete. The model was built using the cohesive zone model (CZM). The zero-thickness cohesive elements were adopted to characterize the mechanical behavior of potential fracture surfaces and rebar–concrete interfaces. The constitutive model for concrete was developed by considering the damage relation and friction effect, and the corresponding constitutive for the rebar–concrete interface (especially ribbed rebar) was developed by considering the influence of normal separation on the tangential bond–slip relation. To validate the proposed meso-model, a series of ribbed RC beams with an initial notch was designed and tested by four-point bending loading to obtain different fracture patterns. Through comparison, the developed RC meso-model was validated to simulate the RC structure's fracture behavior appropriately. The influence of the rebar–concrete interface constitutive model on the simulation results was investigated. The investigation results indicate that neglecting normal separation would result in an overestimation of the structure's stiffness and bearing capacity (the peak load was overestimated by more than 10%). Finally, an analysis was conducted on the energy consumption during the failure process of the RC beams. It was found that the proportion of energy consumption during tensile failure of the beam decreased from approximately 86% to 89% in the early stage to approximately 43% to 52% in the later stage, indicating a transition in the beam's failure mode from tensile failure to shear failure.

      • KCI등재

        Life Prediction of Hydraulic Concrete Based on Grey Residual Markov Model

        Li Gong,Xuelei Gong,Ying Liang,Bingzong Zhang,Yiqun Yang 한국정보처리학회 2022 Journal of information processing systems Vol.18 No.4

        Hydraulic concrete buildings in the northwest of China are often subject to the combined effects of lowtemperaturefrost damage, during drying and wetting cycles, and salt erosion, so the study of concretedeterioration prediction is of major importance. The prediction model of the relative dynamic elastic modulus(RDEM) of four different kinds of modified concrete under the special environment in the northwest of Chinawas established using Grey residual Markov theory. Based on the available test data, modified values of thedynamic elastic modulus were obtained based on the Grey GM(1,1) model and the residual GM(1,1) model,combined with the Markov sign correction, and the dynamic elastic modulus of concrete was predicted. Thecomputational analysis showed that the maximum relative error of the corrected dynamic elastic modulus wassignificantly reduced, from 1.599% to 0.270% for the BS2 group. The analysis error showed that the modelwas more adjusted to the concrete mixed with fly ash and mineral powder, and its calculation error wassignificantly lower than that of the rest of the groups. The analysis of the data for each group proved that themodel could predict the loss of dynamic elastic modulus of the deterioration of the concrete effectively, as wellas the number of cycles when the concrete reached the damaged state.

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