Table of Content

25 August 2017, Volume 45 Issue 8

Previous Issue    Next Issue

Automotive Engineering

Dynamic Response Analysis of a Transmission Housing Under Variable Speed Conditions

ZANG Meng-yan MENG Ning CHU Shu-min CHEN Yong

2017, 45(8):  1-6.  doi:10.3969/j.issn.1000-565X.2017.08.001

Asbtract ( 228 )   PDF (864KB) ( 358 )  

Related Articles | Metrics

Based on the dynamic theory of the multi-body system,a dynamic model of a gear transmission system is constructed by taking into account the effects of the time-varying mesh stiffness，the tooth backlash,the bearing stiffness and damping，and the speed variation.Then，the dynamic meshing forces of gears and the dynamic forces of housing bearing seats are calculated,and after a flexible housing model is constructed，the natural frequency and modal shapes of the transmission housing are obtained.Finally,by taking the dynamic forces of the housing bearing seats as the excitation,the modal superposition method is adopted to calculate the dynamic response,thus acquiring the information relative to the vibration of the nodes on the housing surface.Simulation results show that,when a constant torque is applied,the vibration acceleration amplitude of the housing surface increases with the increase of the rotating speed,which accords well with the experimental results within a margin of error of 10%.

Lightweight Design of Bus Frame Constrained by Static and Dynamic Stiffness

ZUO Wen-jie MA Hong-gang GUI Chun-yang LI Hang

2017, 45(8):  7-12.  doi:10.3969/j.issn.1000-565X.2017.08.002

Asbtract ( 354 )   PDF (678KB) ( 261 )  

Related Articles | Metrics

In order to achieve a lightweight structure of the bus frame consisting of rectangular tubes,first,the cross-sectional properties of the rectangular tubes are calculated,and the responses of static bending stiffness,static torsional stiffness，and dynamic frequency stiffness are respectively defined.Next,a structural optimization model of the bus frame is constructed.In the model，the objective function is the structural mass,the design variables are the cross-sectional breadth,height,and thickness of the rectangular tubes,and the constraints are the bending,torsional and frequency stiffness.Then,the sensitivity information of the responses with respect to the design varia- bles is derived,and the nonlinear optimization model is solved through the sequential linear programming.Finally， by a numerical example,it is proved that the proposed method can efficiently acquire the optimal bus frame that satisfies the constraint conditions.

Investigation into Dynamic Characteristics of Semi-Active Hydraulic Damping Strut

2017, 45(8):  13-20,41.  doi:10.3969/j.issn.1000-565X.2017.08.003

Asbtract ( 241 )   PDF (1182KB) ( 372 )  

Related Articles | Metrics

In this paper,first,a semi-active hydraulic damping strut is made equivalent to a two-DOF model of mass and spring,and a dynamic stiffness expression is derived.Next,a nonlinear rubber bushing model based on the linear elasticity,the fractional derivative and the friction model,is constructed,and the Maxwell model is adopted to describe the stiffness of a general damper.Then,the parameters in the dynamic stiffness model of the rubber bushing and the general damper are identified by means of the least square method.Finally,the dynamic stiffness of the semi-active hydraulic damping strut under power-on conditions is compared with that under power-off condition through experiments and simulations,and the influence of the equivalent spring stiffness,the damping constant and the rubber bushing stiffness on the dynamic stiffness and damping capacity of the semi-active hydraulic damping strut is analyzed.The results show that (1) the dynamic stiffness of the semi-active hydraulic damping strut increases with the increase of the rubber bushing stiffness,the equivalent spring stiffness and the damping constant; (2) increasing the damping constant helps to improve the dynamic stiffness of the semi-active hydraulic damping strut at low frequencies,and decreasing the rubber bushing stiffness and the equivalent spring stiffness helps to reduce the dynamic stiffness of the semi-active hydraulic damping strut at high frequencies; (3) the ru- bber bushing stiffness has a smaller effect on the damping capacity of the semi-active hydraulic damping strut; and (4) the smaller the equivalent spring stiffness and the damping constant are,the better the damping capacity of the semi-active hydraulic damping strut will be.

Development of Finite Element Model of Impact Injury to Upper Limb of Chinese Human Body

CHEN Ji-qing LIU Chao-yang LAN Feng-chong

2017, 45(8):  21-27.  doi:10.3969/j.issn.1000-565X.2017.08.004

Asbtract ( 246 )   PDF (857KB) ( 452 )  

Related Articles | Metrics

The investigation into injury biomechanics of Chinese human body orients to offer scientific data for im- proved Chinese automobile safety regulations.In order to investigate the injury response and mechanism of Chinese human body,a finite element model of the upper limb for Chinese 50th percentile male occupants is constructed based on the anatomical structures by CT scanning.The model is detailed into the bones and the soft tissue (name- ly the joint,the ligament,the muscle and the skin) of the upper limb.Then,according to the non-uniformity of the long bone section,a numerical model of the cortical bone section is constructed by continuously changing thick- ness and shape.Finally,by experimental data summarized from the past mortal human subjects,the reliability of this model is verified under the quasi-static and dynamic loading,and the response of the shoulder joint in a side collision is also analyzed.The result shows that the constructed the models can fairly reflect the injury characteris- tics of the upper limb.

Effect of Accelerator Pedal on Driver's Lower Extremity Injury

WU Jun LIU Yu-hao YAO Yuan CAO Li-bo

2017, 45(8):  28-34.  doi:10.3969/j.issn.1000-565X.2017.08.005

Asbtract ( 263 )   PDF (878KB) ( 295 )  

Related Articles | Metrics

In frontal crashes,the accelerator pedal has a direct impact on the driver's feet，and its mechanical property is one of the main factors affecting the driver's lower extremity injury.However,in the current simulation researches on the driver's lower extremity injury,the accelerator pedal is often ignored or simulated by using the ri- gid body model,which cannot accurately reflect the effect of the pedal on the driver's lower extremity and cannot be used to analyze the effect of the pedal fracture on the driver's lower extremity injury.In order to solve these prob- lems,a detailed finite element model of the accelerator pedal is constructed,and it is proved to be effective through six groups of pedal component tests.Based on this model,the effects of the pedal friction coefficient,the rotation stiffness,the travel and the intrusion volume,the fracture torque on the driver's lower extremity injury are re- vealed.The results show that the fracture torque of the pedal has a significant effect on the lower extremity injury.Specifically,reducing the fracture torque can greatly decrease the driver's tibia force and tibia index,thus reducing the risk of the lower extremity injury.This research result also highlights the value of the breakable pedal designing on the driver's lower extremity protection,and can be taken as a reference for the structure design of accelerator pedals.

Simulation of PEMFC Based on Non-Uniform Porosity of GDL

ZHANG Zhi-ming SHEN Zhe-min SHANG Ya-peng PAN Tao

2017, 45(8):  35-41.  doi:10.3969/j.issn.1000-565X.2017.08.006

Asbtract ( 359 )   PDF (672KB) ( 544 )  

Related Articles | Metrics

At present,for the numerical simulation of the PEMFC (Proton Exchange Membrane Fuel Cell) perfor- mance,it is assumed that the porous media in the GDL (Gas Diffusion Layer) has a constant porosity.But in fact,the GDL deformation caused by the compression of bipolar plate ribs can lead to the non-uniform porosity of the GDL.In this paper,aiming at the GDL deformation and the non-uniform porosity,which are caused by the assembly pres- sure,based on the finite element theory and the computational fluid dynamics software,a non-uniform porosity func- tion (UDF,User Defined Function) is deduced by introducing the structural mechanics analysis into a FLUENT simu- lation model.Simulation results show that,for the GDL below the rib,the changes of the porosity cause the gas flow rate in the longitudinal section in the Y direction to increase from the middle to the bipolar plates,and that,due to the nonuniformity of the porosity,the gas concentration below the rib is lower than that below the flow chan- nel,and the water content increases leads to a water accumulation phenomenon,which are negative to maintaining the performance of fuel cells.Moreover,the accuracy of the deduced function is verified,meanwhile the change rules of the operating temperature and humidity with the fuel cell voltage are discussed,and the temperature distribution inside the fuel cell is also investigated.It is found that the temperature of the electrochemical region at the cathode side below the flow channel is higher than that at the anode side,which reflects that,for the actual fuel cell,the water accumulation phenomenon at the cathode side causes its heat transfer speed to be slower than that at the anode side.

Traffic & Transportation Engineering

Forward Kinematics of Test Bench for Bogie Parameters

WANG Qi-ming SU Jian NIU Zhi-hui LIN Hui-ying XU Guan

2017, 45(8):  42-49.  doi:10.3969/j.issn.1000-565X.2017.08.007

Asbtract ( 197 )   PDF (1056KB) ( 297 )  

Related Articles | Metrics

The existing Newton-Raphson iterative method used for the forward kinematics of parallel mechanisms has a strong dependency on the initial value with a slow iteration convergence speed,and thus the instantaneity can- not be satisfied.In order to solve these problems,a combinatorial method of a new improved BP Neural Network model based on the Levenberg-Marquardt algorithm and the high-order modified Newton-Raphson (HMNR) itera- tion method is proposed to achieve the forward kinematics of Redundancy parallel mechanism.Then,by taking a test bench for bogie parameters (TBBP) as the example,the track spectrum is converted to the displacement of the actuator with the help of the invert kinematics.Hydraulic system received the instruction of displacement to propel the test bench's coupling motion,which is used to simulate the running status of the real vehicle or bogie on real tracks.By using a mass of actual data as the training material,the initial value of the forward kinematics of the test bench is thus determined,which is then compared with those obtained through the neural network models respec- tively based on the quasi-Newton algorithm BFGS and the scaled conjugate gradient (SCG) algorithm.Experimen- tal results show that the L-M algorithm model is obviously superior to the BFGS algorithm model and the SCG algo- rithm model in terms of the error performance analysis,with a predicted angle value of less than 4 ×10 －7 and a dis- placement error of less than 8 ×10 －4 .In addition,the predicted value is taken as the initial value of the HMNR method to perform an iterative calculation,which causes a 41% reduction in the required iterations and a 23% re- duction in the iteration time in comparison with the Newton-Raphson (NR) method.Finally,by applying the hy- brid strategy on the TBBP for testing the relative position and attitude of adjacent vehicles,the effectiveness of the hybrid strategy is further validated.

Driving Fatigue Quantization Based on Entropy Weight Method

LI Shi-wu YIN Yan-na WANG Lin-hong XU Yi

2017, 45(8):  50-56.  doi:10.3969/j.issn.1000-565X.2017.08.008

Asbtract ( 208 )   PDF (322KB) ( 328 )  

Related Articles | Metrics

In order to obtain the judging threshold of the driving fatigue objectively and accurately,the driver's eye movement data,reaction time and execution time under the sober and mental fatigue states are collected from a driving simulator.The driver's eye movement data,reaction time and execution time during continuous driving are used to respectively describe the driver's gaze characteristics,reaction ability and executive ability.Then,a rela- tionship model is constructed by adopting the entropy weight method to obtain the weighted average of the three kinds of data.In the model,the three kinds of data and the quantitative values of the driving fatigue are respec- tively taken as the independent and dependent variables.In order to improve the objectivity of the driving fatigue threshold,the variable threshold determination method is adopted to select the thresholds of the optimal fatigue at the first fatigue threshold and the secondary fatigue threshold.Moreover,the change rules of the driver fatigue un- der the continuous driving condition are revealed,and the quantitative method of the driving fatigue is evaluated.Experimental results show that the proposed method can effectively improve the precision of the driving fatigue quantization,and it has a broad application prospect in the driving safety field based on the prevention of driving fatigue.

Origin Destination Constraint Experience Model of Taxi and Path Planning

PAN Xiao-fang ZHOU Shun-ping YANG Lin WAN Bo

2017, 45(8):  57-64,83.  doi:10.3969/j.issn.1000-565X.2017.08.009

Asbtract ( 259 )   PDF (1494KB) ( 468 )  

Related Articles | Metrics

Extracting the driver's experience from taxi trajectories to guide the public travel is an important applica- tion of trajectory data.In order to avoid the inaccurate results caused by ignoring the origin and destination in the experience extracting process of traditional methods,this paper proposes an origin destination constraint experience model (ODCEM). Then,the traditional experience model,the ODCEM and the shortest path model are com- pared by the experiments in Shenzhen city.The results shows that (1) the ODCEM can successfully simulate the taxi driver's travel experience during the experience extracting and the path planning; (2) in comparison with the other two methods,the ODCEM increases the travel time and the speed respectively by more than 93. 3% and more than 76. 7%; and (3) the travel distance of the ODCEM is between those recommended by the other two methods.Finally,the influence of the constraint scale is discussed.It is found that the desirable constraint size is 2km ×2km.

Design of Detector Location for Priority Control of Modern Streetcar at Intersection

WANG Bao-jie XIANG Yun WANG Wei FU Min LI Ye

2017, 45(8):  65-69.  doi:10.3969/j.issn.1000-565X.2017.08.010

Asbtract ( 230 )   PDF (519KB) ( 282 )  

Related Articles | Metrics

The application of the actuated signal control at urban intersections is an important measure to ensure the advantages of modern streetcars in energy saving,environment protection,comfort and efficiency.Aiming at the problem of the installation site of vehicle arrival detectors at intersections,a design method of the detector position is proposed for the modern streetcars with priority control at intersections.First,according to the priority control strategy of the modern streetcars at intersections and their arrival time at stop lines,the situations of the modern streetcars waiting for green lights are divided into seven types,and the calculation methods for the waiting time of green lights are respectively put forward.Next,by analyzing the displacement relationships among detectors,stops and upstream adjacent intersections,a computing model for the detector position is constructed.Finally,the validi- ty and feasibility of the proposed design method are testified by using the planning data and current traffic real-time data of Nanjing Hexi modern streetcars.The results show that the proposed design method is practical,and it has a good prospect for engineering applications.

Investigation into Pricing Game of Customized City Bus Service

GONG Hua-wei JIN Wen-zhou HAO Xiao-ni LUO Qiang

2017, 45(8):  70-76.  doi:10.3969/j.issn.1000-565X.2017.08.011

Asbtract ( 215 )   PDF (305KB) ( 328 )  

Related Articles | Metrics

The customized city bus service is a new form of public transport,which is a kind of supplement and im- provement to the urban public transport system,and thus it has brought about a change in the urban public transit travel mode.In this paper,by analyzing the travel mode choice probability model of urban residents and by taking the maximum of total passenger ticket revenue of the customized city bus service and the conventional urban bus transportation as the target,a game model of the passenger ticket revenue between the customized city bus service and the conventional urban bus transportation is constructed.Then,the game solution is obtained and an actual case for this model is calculated.The results show that a reasonable fare plan formulation will be able to provide balanced development conditions for the two bus modes and promote the coordinated development of different trans- port modes,which helps to achieve the goal of the public transport priority in the urban traffic development.

Effect of Combination Mode of Traffic Guidance Information on Route Decision-Making

2017, 45(8):  77-83.  doi:10.3969/j.issn.1000-565X.2017.08.012

Asbtract ( 236 )   PDF (502KB) ( 284 )  

Related Articles | Metrics

In order to improve the induction efficiency of the guidance information and reveal the effect of the struc- tured information on the driving decision-making,a traffic guidance information evaluation system is built by intro- ducing a cloud model,and by a simulation in a full-featured car driving simulator,four kinds of traffic guidance information environment are designed to conduct route choice experiments.Then,the effect of the traffic guidance information with different combinations of structured information on the driving decision-making is analyzed,and an optimization scheme of the traffic guidance information release strategy is proposed.The results show that the traffic guidance information including the digital information,the language information and the image information has a significant effect on the driving decision-making.Specifically,a combination of the language information and the digital information is beneficial for drivers to perceive the road environment,and a combination of the digital infor- mation and the image information is beneficial to the route decision of drivers.

Optimization Model of Airport Bus Line Network Reliability and Algorithm Design

BAO Dan-wen LIU Jian-rong GU Jia-yu

2017, 45(8):  84-91.  doi:10.3969/j.issn.1000-565X.2017.08.013

Asbtract ( 267 )   PDF (634KB) ( 411 )  

Related Articles | Metrics

In order to quantify the reliability of airport bus line networks,a reliability prediction model of the air- port bus travel time is constructed based on the BP neural network.Next,an optimization model of the airport bus line network is constructed,the objective of which is to maximize the reliability,and such constraints as time,sites and services are taken into account.Then,the Hill-climbing algorithm is adopted to achieve the initial solutions for the lines,and a fitness function based on the reliability is established.Finally,a hybrid genetic algorithm with dif- ferent mutation and crossover rates is designed to solve the constructed optimization model.Case study results show that (1) during peak hours,the reliability of the bus line network at Nanjing Lukou International Airport is only 0. 62,the reliability of inner city roads is about 15% lower than that of outer city roads,and the overall reliability is at a low level; (2) the optimization process through the hybrid genetic algorithm is greatly affected by the cross- over and mutation rates,and lower crossover rate and higher mutation rate can increase the instability of the optimi- zation process; and (3) when the crossover rate is 0. 9 and the mutation rate is 0. 05，the objective function value of the constructed optimization model is 0. 79,and the reliability is 11. 5% higher than that before the optimization,which means that the optimization effect is significant.This method provides a scientific basis for the optimization of the bus line network of airports and the corresponding efficiency improvement of the external transport services.

Structural Dynamic Response Analyses of AHTS in Side Collision with Offshore Platform Pile

WU Jia-ming LU Yu-fan LIAO Hua LU Li-hua

2017, 45(8):  92-102.  doi:10.3969/j.issn.1000-565X.2017.08.014

Asbtract ( 243 )   PDF (1174KB) ( 378 )  

Related Articles | Metrics

The side collision is one of the most dangerous working conditions in the AHTS (Anchor Handling To- wing Supply Vessel) collisions at sea.In this paper,the structural dynamic responses in the side collision of the AHTS with the offshore platform pile are numerically simulated in time domain by means of the finite element me- thod.Then,the structural dynamic behaviors of the AHTS hull deformation damage and the transforming processes of the colliding energy are analyzed,and the main reasons for the structural damage of the AHTS hull,the structu- ral failure characteristics and destruction modes,and the anti-impact functions of different kinds of structures in the collision zone are also discussed.Moreover,the mechanical mechanisms of the hull destruction caused by the side collision are investigated.Simulation results indicate that (1) there exists apparent local destruction effects on the collided structures; (2) the structural damage mainly occurs in or near the collision zone,and away from that zone,there exists little collision influence; and (3) when the structural destruction caused by the side collision happens,the kinetic energy of the AHTS motion is mainly transformed to the structural internal energies,which are manifested in the forms of stretching,bending,crushing and rupture in the collision zone,and the horizontal struc- tures in the collision zone bear more colliding loads than the vertical ones.

Architecture & Civil Engineering

Seismic Response of High-Flexible Structure Under Multi-component Ground Motion

WEI Wen-hui HUANG Wei-song XUE Guang-wen ZHANG Di

2017, 45(8):  103-109.  doi:10.3969/j.issn.1000-565X.2017.08.015

Asbtract ( 262 )   PDF (650KB) ( 309 )  

Related Articles | Metrics

In this paper,the seismic response of the high-flexible structure under coupled horizontal,tilting and vertical ground motion is investigated.First,a dynamic equation under the coupled ground motion is derived,in which the additional second-order effects of gravity caused by the foundation tilt under the tilting ground motion is taken into consideration.Then,the influence of the vertical ground motion on the second-order effects of gravity is discussed.Finally,by taking a 210 m television tower as the prototype,the shaking table test of a reduced scale model is carried out under the coupled ground motion.The comparison between the theoretical analysis results and the test ones show that (1) the results of the shaking table test accord well with the theoretical ones obtained through the derived dynamic equation,which testifies the rationality and accuracy of the theoretical analysis; (2) the vertical ground motion can cause the change of the conventional second-order effects of gravity to change,and it has an significant impact on the additional second-order effects of gravity caused by the tilt; and (3) as compared with the single horizontal ground motion,the coupled ground motion causes the geometric rigidity to change with time and results in a larger asymmetric displacement，which means that the structure capable of resisting the hori- zontal ground motion originally may get destroyed.

Analysis and Monitoring of Unloading Process of High-Rise Suspended Structure

SHI Kai-rong Lü Jun-feng JIANG Zheng-rong PAN Wen-zhi

2017, 45(8):  110-119.  doi:10.3969/j.issn.1000-565X.2017.08.016

Asbtract ( 253 )   PDF (1300KB) ( 342 )  

Related Articles | Metrics

Due to the fact that the high-rise suspended structure is of a long cantilever span and the construction of the structure is very difficult,when the forward construction method is adopted,the temporary support should be set under the suspended structure,and it can't be removed until the suspended structure is integrated with the main structure.The unloading process of the temporary support is very important,because the structural bearing system is converted during the process.In order to verify the reliability of the unloading technology and ensure the struc- tural safety,by taking a complex high-rise suspended structure of Zhuhai Renheng Marine Center as the example,the unloading process is analyzed respectively by means of the displacement control and the support reaction force control,and the stress of the key members and the vertical deformation of the key nodes are monitored during the unloading process.The comparison between the unloading analysis results and the monitoring data shows that the results of the displacement control unloading and the supporting reaction force unloading are close to each other,and that they accord well with the monitoring data,and that,after the unloading,a whole structural bearing sys- tem forms and it tends to be stable.On this basis,the unloading sensitivity of the suspension structure is investiga- ted.By analyzing the most unfavorable supporting reaction force and the supporting point deformation,it is con- cluded that the failure of one support point in the unloading process can cause the reaction forces of the adjacent support points as well as the vertical deformation and the member stresses of the upper truss to change greatly.Therefore,effective measures should be taken to avoid such unexpected problems in the unloading process.

Attack Angle Effects of Flutter Optimization of a Steel Truss Bridge and Corresponding Isolated Improvement

CHEN Xing-yu WANG Bin LI Yong-le LIAO Hai-li CHEN Ke-yu

2017, 45(8):  120-125,138.  doi:10.3969/j.issn.1000-565X.2017.08.017

Asbtract ( 195 )   PDF (529KB) ( 331 )  

Related Articles | Metrics

Steel truss girders are a common structure type for long-span suspension bridges.The flutter stability of this structure type is poor.Therefore,aerodynamic optimization measures are usually adopted to increase the criti- cal wind speed of the flutter.In this investigation,based on a long-span steel truss girder bridge located at a mountain area,the wind tunnel tests of the section model were conducted to detect the critical wind speed of the flutter,and the influences of the general aerodynamic measures including the central stabilizer,the horizontal sta- bilizer and the stabilizer under the top lateral bracing on the critical wind speed of the flutter were discussed.It is found that the general aerodynamic measures have attack angle effects on the critical wind speed of the flutter.Therefore,isolated aerodynamic measures are proposed,which include the isolated horizontal stabilizer,the grat- ing horizontal stabilizer and the isolated stabilizer under the top lateral bracing.The results show that these isolated aerodynamic measures can improve the attack angle effects to a certain degree,thus increasing the critical wind speed of the flutter.

Theoretical Analysis and Numerical Simulation of Large-Diameter and Thin-Wall Pipelines During Ultra-Deep J-Lay Installation

ZHANG Yong-qiang

2017, 45(8):  126-131.  doi:10.3969/j.issn.1000-565X.2017.08.018

Asbtract ( 183 )   PDF (521KB) ( 158 )  

Related Articles | Metrics

In this paper,a nonlinear differential equation of pipelines is established by considering the BRAZIER effect.Then,the analytical solution to the J-Lay pipeline configuration is obtained through the singular perturbation theory,and such key parameters as the bending moment and the axial force of the pipeline are solved by means of the iterative method.Meanwhile,the analytical solution of the pipeline is proved to be correct by means of the finite element method.Finally,the influences of the tension,the water depth and the ocean currents on the configuration and bending moment of the J-Lay pipeline are investigated.Theoretical results show that (1) in the laying process of the J-Lay pipeline,the peak of the bending moment is always present in the pipeline section near the touch down point; (2) when the tension is increased in a certain range,the more smooth the pipeline configuration is,the smaller the peak value of the bending moment will be,which is beneficial to the pipeline laying; (3) when the other parameters are constant and the water depth increases,the increase of the bending moment peak value of the pipeline is not monotonous; and (4) when the current force is in the opposite direction of the pipe laying,the ben- ding moment peak value of the pipeline increases,which is detrimental to the pipeline laying.

Self-Monitoring Performance of Cracking Development of Multiphase Conductive Concrete Subjected to Bending

DING Yi-ning HENG Zhen HAN Zhi-bo

2017, 45(8):  132-138.  doi:10.3969/j.issn.1000-565X.2017.08.019

Asbtract ( 222 )   PDF (701KB) ( 311 )  

Related Articles | Metrics

By adding the macro steel fiber (SF),the carbon fiber (CF) and the nano-carbon black (NCB) into the concrete as the multiphase conductive materials,the influences of the SF,the CF and the NCB on the mechani- cal properties and conductivity of the cracked concrete as well as on the self-monitoring performance of the crack development are investigated.Then,a relationship between the fractional change of the surface resistance (FCR) and the crack opening displacement (COD) of the conductive concrete beams is established.The results show that (1) the addition of the conductive materials can greatly enhance the flexural strength and toughness of the con- crete; (2) the hybrid use of the NCB,the CF and the SF shows a clear positive hybrid effect on the flexural beha- vior and the self-monitoring performance of the crack development; and (3) there is a linear relationship between the FCRand the COD.

Prediction of Pedestrian Flow in Commercial Buildings Based on an Integration Technology of Space Syntax and Arc GIS

DENG Meng-ren GUO Hao-xu ZHOU Wei-qiang

2017, 45(8):  139-145,152.  doi:10.3969/j.issn.1000-565X.2017.08.020

Asbtract ( 148 )   PDF (1050KB) ( 397 )  

Related Articles | Metrics

In order to effectively predict the space using value and the pedestrian flow,the effect of the architectu- ral spatial organization on the pedestrian flow is investigated.In the investigation,by taking the commercial build- ing as the objective and based on two typical samples,an integrated technology of Space Syntax and Arc GIS is used to quantitatively analyze various inner circulation spaces in the commercial space.This technology has its own advantage in the purpose of making the feedback mechanism between theory and reality.The research data indicate that (1) for a commercial space with a stable tenant combination,the pedestrian flow can be effectively predicted by considering the main entrance location, commercial space; space syntax; geographic information systems; spatial organization; pedestrian
flowthe vertical transportation and the spatial integration; (2) reasonable vertical transportation and tenant combination can help various pedestrian flows to arrive at their destination more conveniently; and (3) the interior space of the commercial space has a strong symmetry,and a clearer spatial or- ganization and a more integrated form help to achieve an equilibrium pedestrian flow.

Effects of Modular Ecological Wall on Exterior Light-Thermal Environment of a Building

CHANG Na LI Deng-wu

2017, 45(8):  146-152.  doi:10.3969/j.issn.1000-565X.2017.08.021

Asbtract ( 249 )   PDF (626KB) ( 349 )  

Related Articles | Metrics

By taking a built square in Guangdong as the objective,the temperature,humidity and illuminance of the exterior of the modular ecological wall are quantitatively compared with those based on the bare wall,so as to reveal the effects of the modular ecological wall on the exterior light-thermal environment of the building.The re- sults show that (1) as compared with the bare wall,the modular ecological wall can significantly increase the hu- midity and decrease the temperature，and it causes a lower illuminance; (2) in comparison with the bare wall,the modular ecological wall reduces the exterior temperature by up to 5. 1℃ in a day,and it can significantly re- duce the energy consumption of the building; (3) the relative humidity of the exterior of the modular ecological wall is at most 23% higher than that based on the bare wall; and (4) the modular ecological wall has a better shading effect than the bare wall; specifically,the former can reduce the illuminance by 99. 4% at most.There- fore,the modular ecological wall is an effective,active way of thermal insulation and energy saving,which can produce good comprehensive benefits in energy saving.