Abstract:Bridge health monitoring (BHM) system produces a huge amount of monitored data in the longterm service periods, the proper handling of which for dynamically predicting the structural reliability is one of the main difficulties in the BHM field. To reasonably predict timevariant reliability of inservice bridges, in this paper, the linear dynamic models (monitoring equation and state equation) with optimum discount factors are built based on the longterm everyday monitored extreme stress data of BHM system. Then, the onestep forward prediction distribution parameters of monitored extreme stress and the posteriori distribution parameters of state variable are respectively predicted by using the Gaussian particle filter prediction algorithm with discount factors. Finally, the dynamic reliability indices of bridge are predicted using the first order second moment (FOSM) method, and the monitored data of an actual bridge is provided to illustrate the application and feasibility of the proposed method, which can provide the theoretical foundation for preventive maintenance decision of the actual bridge.

Abstract:In order to investigate the antiblast performance of Hsection steel columns at blast and prefabricated fragments, the damage effect of the combined blast and fragments loads on the Hsection steel column is simulated by arranging the prefabricated fragments around the cylindrical TNT based on the nonlinear finite element software ANSYS / LSDYNA .The difference of dynamic response of Hsection steel columns at blast load, fragments load, and combined blast and fragments load is analyzed. Meanwhile, the influence of axial compression ratio, steel strength, slenderness ratio, and cross section type on the dynamic response of the steel column at combined blast and fragments load is investigated by using the parametric analysis method. The research indicates that the combined effect of blast and prefabricated fragments under adjacent explosion has a superposition enhancement effect and the combined load is bigger than the linear superposition of single load effect. In the antiblast design of steel columns, the value of the axial pressure should be controlled, and when the steel strength grade is Q235 the axial compression ratio should not be bigger than 0.4. It is reasonable to choose steel strength instead of blindly choosing highstrength steel. By changing the column height to change the slenderness has little effect on the steel column. Tubular crosssection steel column has the best antiblast ability, followed by Hsection and box section.

Abstract:In this paper, a simplified analysis method is proposed based on angle bisector to effectively get the internal forces and deformations of the sliding cable structure. First, the cable constraint caused by the pulley is modeled by fixed hinge. The stressfree length adjustment, internal forces, and alignment of subcables are obtained by using the unstressed length adjustment matrix constrained by the reaction forces vertical to the angle bisector direction equaling zero. Next, the angle of bisector is modified according to the deformed structure. The first step will be iterated until the cable forces are equal within tolerance. An analysis package is programmed based on this and numerical results show that the tension continuity and deformation relationship could be achieved by 2 to 4 iterations with high precision. The numerical example and engineering example demonstrate the correctness and efficiency of the proposed method.

Abstract:To investigate the influence of bearing plate position on load bearing properties and mechanism of connections in hybrid towers, tests of reducedscale specimens with front bearing plate or back bearing plate, which are related to two hybrid towers in cablestayed bridges, were conducted. In these studies, strains of both concrete and steel plate and the slip between two materials were measured, and the differences between the specimen with front bearing plate and that with back bearing plate were compared as well. The results show that the existence of a bearing plate, which will bear approximately 40% of the loadings, can lead to a reduction in the shear force taken by shear connectors. Because of the important role played by the bearing plate, the slip between steel and concrete in the joint connection will decrease. In addition, the distribution of shear connectors is highly related to the location of bearing plate. Generally speaking, the joint connection with bearing plate with front bearing plate or back bearing plate can be considered as an excellent construction type in hybrid towers due to their outstanding performance in the cooperation of the bearing plate and shear connectors.

Abstract:Small strain stiffness properties of soil play an important role in predicting the deformation of deep foundation pit and tunnel excavation. This paper used oedometer, stress path triaxial apparatus, and resonant column apparatus to measure the small strain stiffness properties of three typical undisturbed soils in Changzhou, Jiangsu province. The parameters involved in the hardening soil model combined with the small strain model (HSS), including the initial shear modulus, modulus reduction curve, the soil strength parameters, and unloading and reloading modulus, were determined. The influence of effective stress on small strain stiffness properties was also studied, and suggestions were proposed on how to choose suitable small strain model parameters.

Abstract:The main focus of this paper is to study lanechanging decisionmaking characteristics in freeway offramp areas and analyze the mechanism of lanechanging decisionmaking. Using driving behavior samples and vehicle operating data collected from Shanghai Naturalistic Driving Study, the departure samples are selected according to the driving path and specific range of exit with Google Earth. Then lanechanging behaviors can be identified by lane offset position and steering wheel angle. Furthermore, illustrated by the example of the 8lane freeway (four in each direction), this paper comprehensively considers driving route information and traffic flow environment as factors. On this basis, relying on the random utility theory, the binary logic (BL) model is adopted for fitting lanechanging decisionmaking model so that the lane utility function is obtained. After graphing utility of different lanes in offramp areas respectively in free flow, steady flow and congested flow, the homogeneity and heterogeneity analysis are conducted. The result indicates that the accuracy of the model comes to 86.21% and the influence of each factor can be reasonably explained. Besides, according to utility analysis, the lanechanging behavior of leaving vehicles is a consequence of the balance between leaving willingness and requirement for improving driving environment. In other words, it combines the characteristics of mandatory and discretionary incentives. Moreover, in the process of traffic transforming from free flow to heavy flow, the influence of the latter increases: the position at which drivers start to perform right lanechanging gradually approaches the diverging area and left lanechanging behavior is more active in upstream section.

Abstract:In order to investigate drivers’ car following behaviors under hazy weather conditions, by using the high fidelity driving simulator with a motion system of 8 degrees of freedom, two scenarios, namely clear weather conditions and hazy weather conditions, were established to collect and analyze the key variables of car following behaviors including the time/distance headway, delay time and acceleration/deceleration rate at different car following stages under different traffic conditions. Compared to the clear weather conditions, the results indicate that hazy weather conditions have significant effects on drivers’ car following behaviors; the maximum distance headway significantly increases by 8.7%, 19.4%, and 25.6% under car following stages in case of freeflow conditions, congested conditions, and jam conditions, respectively. The minimum distance headway significantly increases by 13.0% under car following stage in case of freeflow conditions. The minimum time headway significantly decreases by 47.9%, and the mean value and the discreteness of the delay time significantly increases by 15.5% and 28.2% respectively, under car following stage in case of jam conditions. Drivers become more cautious in accelerating under hazy weather conditions. There exist significant differences in car following behavior at car following stages under different traffic conditions. With the increasing speeds, both the mean value and the discreteness of the maximum/minimum distance headway and the delay time increase significantly, while the time headway decreases followed by increasing afterwards.

Abstract:This paper aimed to help to provide a more comprehensive evaluation of the intersection taking into account both safety and efficiency. The conflicts during turningright processes in the typical fourphase intersections were studied. The rightturn event chain model was built. And traffic conflicts and delay between rightturn motor vehicles and other motor vehicles, nonmotor vehicles, and pedestrians were analyzed in detail. The reliability method was introduced to quantify the safety from the perspective of probability while traffic delay was used to measure the efficiency. Besides, the Monte Carlo method was used to simulate the intersections to effectively calculate the reliability and delay of event chains. When assessing the intersections, the public psychological tolerance and intersection service level were referred to. This study can provide scientific basis for intersection optimization.

Abstract:This paper proposes a parking demand forecasting method based on consistent feature in parking demand of buildings with similar functions. First, an “influencing factor correction coefficient method” is established based on the parking demand generation rate of different buildings nowadays. The parking demand generation rate of buildings can be forecast with different functions in the planning year. Secondly, the parking demand peak ratio is used to describe the daily distribution of buildings, and “threestep model of parking demand” is established with the concept of shared parking. Finally, the peak parking demand of complex is achieved. This model is applied to a complex project in Shenyang.

Abstract:Urban mass transit is playing a significant role in supporting and promoting urban development. An important indicator for the planning and design of urban rail transit may be succinctly summarized by passenger flow models within a peak hour; one important feature of the model is the maximum singledirection flow. To determine this feature, it is necessary to forecast passengers’ departure time and route choice during a peak period. As the basis of this process, the peakperiod stationtostation origindestination (OD) matrix reflects passengers’ travel needs. This paper tests the traditional gravity models to find the pattern that forecasts the peakperiod stationtostation OD matrix in urban rail transit. A realworld case study of Chongqing, China, is used as a model performance measure. To alleviate its overestimation when the effect of the deterrence function between two stations is too small, the gravitymodelbased peak period coefficient (PPC) model is introduced. By comparing the PPC and gravity models using the same dataset, the results indicate that the PPC model is superior to the gravity model. The standard deviation of the PPC model is 12.90 passengers, which is 56.02% lower than that of the gravity model, which is 29.33 passengers.

Abstract:Novel online estimation algorithms of train adhesive force were proposed for antiskid control. Since it is difficult to measure the adhesive force, it is of significance to make full use of adhesive force in antiskid control. In this paper, a wheel set dynamic model is established first. Then, using the Calman filter, extended state observer and so on, five online estimation algorithms for train adhesive force were designed, where the axle speed and the equivalent clamping force were the input. Furthermore, with the simulink software platform, signal noise contamination and transmission delay were set, and two conditions of constant adhesive force and variable adhesive force were simulated. Simulation results reveal that the five algorithms could be used to estimate the adhesive force, but when the response time and the maximum error of adhesive force estimation are taken into account, the nonlinear expansion state observation algorithm is the best algorithm for adhesive force estimation. Finally, the accuracy of the estimation algorithm is further validated by using measured data.

Abstract:To solve the problem of multiobjective tool trajectory of painting robot for ruled surface the fitting film thickness data were collected from the planar painting experiment. By using the MATLAB genetic algorithm toolbox, the β distribution was obtained. The paint thickness growth model for ruled surface was established based on the planar paint thickness distribution. The surface was discretized into a set of points, and the tool path was fitted by the cubic B spline curve. A multiobjective optimization model was built aimed to get uniform paint thickness on curved surface and high painting efficiency, and an improved fast and elitist nondominated sorting genetic algorithm(NSGAⅡ) was applied to solve the model. A serial of trajectory optimization schemes were presented. Finally, the trajectory optimization purpose on ruled surface was realized. The case result was compared to verify the effectiveness and practicability of the proposed method.

Abstract:The moving particle semiimplicit (MPS) meshfree particle method was used to analyze the churning loss of gear in the transmission system. The single helical gear was analyzed with such variables as gear width, immersion depth, and rotation speed. The results show rotation speed has the most significant influence on churning loss followed by immersion depth and gear width. Then the churning loss calculation formula was proposed by using the analysis results. The MPS feasibility and accuracy in the domain of churning loss analysis were validated by experiments. This paper provides a new method for gear churning loss research.

Abstract:According to a simplified dynamics model of the linear range extender, the limit cycle of linear range extender was studied in frequency domain by using the describing function method. The nonlinear part of the linear range extender dynamics model was described by using the describing function, and the existence, quantity and stability of the system limit cycle were analyzed by using the image of the describing function and the frequency response function. Then the approximate frequency and approximate amplitude of the limit cycle were obtained. This method can also explore the influence of parameters of the linear range extender on the frequency, amplitude, and relative stability of limit cycles. Finally, the analysis results were verified by the experimental data of a prototype. The results show that when the system parameters are appropriate, the linear range extender has the only stable limit cycle in the physical constraint range, and the fuel injection quantity and the electromagnetic force load have influence on the frequency and amplitude of the limit cycle; the amplitude of the limit cycle is related to its relative stability.

Abstract:To study the mechanism of sound radiation induced by vibration of a car side window glass excited by wind turbulent pressure fluctuation, the front side window glass of a test car was considered in this paper. First, based on the equivalent principle, the boundary window seal was set equivalent to series of spring constraints to realize discrete modeling. Then, a MatlabAbaqus joint simulation optimization platform was built to obtain the best equivalent spring stiffness, so that an equivalent model of boundary constrains of side window glass system was established. After that, the power spectral density of the turbulence pressure fluctuation on the side window glass surface was calculated using the Corcos model, which was used as the excitation of the equivalent model to calculate sound radiation in driver’s ear position with FEM. Finally, a laser vibrometer system was applied to obtain the vibration velocity distribution of the side window glass surface, then the radiated interior noise was calculated with BEM method (semisimulation) based on the test data. A comparison of the calculation results of these two methods shows that the frequency spectra characteristics of sound radiation agree well with each other above 200 Hz, which demonstrates the usability of the calculation method of sound radiation based on the equivalent simplified model of side window glass system and the Corcos model as excitation source.

Abstract:In this paper, the welding control arm of a domestic vehicle is designed for lightweight, using a variety of optimization methods to design a new single stamping lower control arm. The new control arm not only meets the various functions of the control arm of the original welding type, but also has a weight loss of 33.3% compared with the original control arm, achieving the purpose of lightweight.

Abstract:Ice surface velocity is one of the essential parameters for evaluating the mass balance and numerical simulation. In this paper, the research is mainly focused on the estimation of the ice surface velocity by combining the differential interferometry method and the multiaperture interferometry method. The twodimensional ice surface velocity of Lambert Drainage was estimated by employing the proposed method. A comparison between the estimated ice surface velocity and those obtained by using the offset tracking method and historical products was performed to analyze the dynamic characters. The results show that the proposed method is superior to the offset tracking method, and the glaciers in Lambert drainage is stable during the past 20 years.

Abstract:This paper presents a practical novel approach for tilt measurement of ancient pagodas and the criterion quality evaluation. Due to the characteristics (multieaves, dougong and vague edges) of ancient pagodas, it is difficult to select measurement points. The coordinates of the central point of each floor of the ancient pagoda structure is estimated by using the method of ellipse fitting. During the process of fitting space axis of the pagoda, the method of total least square is applied to calculate the result. Besides the inclination and twist of each floor is calculated in order to assess the quality of the pagoda in a comprehensive way. This method is more accurate and detailed than the current tilt measurement method which determines the deformation and inclination of tower structures by the ratio of relative displacement of the tower’s base and top and the height of the tower.

Abstract:Biodegradable polymers, such as polylactic acid (PLLA), polyεcaprolactone (PCL), polyvinylpyrrolidone (PVP), polyacrylonitrile (PAN), polyethylene glycol (PEG), etc. with different ratios were intermittent electrospun to obtain nanofibers. The morphologies, structures, and properties of those nanofibers were characterized by SEM, XRD, FTIR, etc. The degradation behavior of nanofibers was investigated in different solution. By analyzing the use of different degradation behaviors, the carrier for different types of DDS was preliminarily discussed for choosing suitable controllabledegradation carrier for different drugs to construct drug composite nanofibers.

Abstract:Mega construction projects (MCPs) with different types of project components have complex schedule interfaces, which increase the risk of delay in construction period. Taking the Phase III expansion project of Shanghai Pudong Airport as an example, the interface division principles of megaproject implementation were summarized for construction headquarters through the interview with project controlling consultants. Under guidance of the division principle, first, three pairs of main interface projects were identified, decomposed, and encoded by using the WBSMatrix. Secondly, the influence indexes of each key interface point (IP) were analyzed by using the interface network algorithm. Finally, based on the IP embedding model for the overall schedule outline, changes of total duration due to interface optimization were compared, which shows that the effectiveness of the optimization model was proved.