Abstract:To study the distribution characteristics and influencing factors of longitudinal welding residual stresses in high strength Urib stiffened steel plates of Q420 grade, the model test of longitudinal residual stresses in Urib stiffened steel plates were measured using the method of sectioning technique. Besides, a 3D solid thermal elastic plastic finite element method (FEM) was developed by using an element birth and death method to simulate the process of weld filler variation and welding, and the residual stress distribution between high strength steel and common strength steel was analyzed. Furthermore, the effects of flange thickness, Urib thickness, space, width and height on welding residual stresses were studied comparatively. The results show that the welding sequence in bilateral rib has no effect on stress distribution. The longitudinal compressive residual stresses out of weld zone is irrelevant to yield strength. Plate thickness, Urib width and height are the main factors affecting welding residual stresses in high strength Urib stiffened steel plates.

Abstract:The response feature of cablestayed bridge with elastoplastic cable pairs and viscous damper adopted in lateral pylon seismic isolation design under near fault ground motions was investigated. Real near fault ground motions were simulated using the equivalent near fault pulse model, and the three sets of synthetic seismic waves with various pulse periods corresponding to II site condition are synthesized. Based on Yongning Yellow River Bridge, nonlinear time history analysis was performed under the synthetic near fault ground motions, and the effects of variation of design parameters of isolation device on the seismic response of the bridge in terms of relative girderpylon displacement were studied. The results show that the responses under synthetic ground motions are comparable to those records with the same pulse characteristics, which can satisfy the need of engineering practice. Near fault ground motions are likely to cause large displacement response. Therefore, it is strongly recommended that the natural period of the structure should be set apart from the pulse period by properly determining the design parameter of the elastoplastic cables. Allowing certain inelastic behavior of cables does not lead to the increase, sometimes even a decrease, of relative girderpylon displacement response when compared with a hypothetic case where the cables behave elastically all along.

Abstract:To reasonably and dynamically predict the extreme stress information of inservice bridge, in this paper, the nonlinear dynamic models were built including monitoring equation and state equation with the longterm everyday monitored extreme stress data of bridge health monitoring (BHM) system. Then the improved Gaussian mixed particle filter (IGMPF) prediction algorithm was introduced which was obtained by using extended Kalman filter (EKF) and GMPF. IGMPF can predict onestep forward prediction distribution parameters of monitored extreme stress and the posteriori distribution parameters of extreme stress state variable. Finally, an actual example was provided to illustrate the application and feasibility of the IGMPF algorithm built. The IGMPF prediction algorithm can not only obtain the reasonable importance functions of monitored extreme stress states, but also solve the problems of shortterm prediction and low precision of the traditional prediction methods. It provides a theoretical foundation for dynamic response prediction of the actual BHM.

Abstract:A novel method was proposed to enhance the ductility of the near surface mounted (NSM) carbon fiber reinforced polymers (CFRP) strengthening system. The principle of the proposed method is to enable stable and controlled slip of CFRP reinforcements in ultimate state, so as to significantly improve the bending ductility and simultaneously fully use the tensile strength of CFRP without rupture. The related design algorithm was introduced, and the bondslip tests on NSMCFRP system and the bending tests on NSMCFRP strengthened reinforced concrete (RC) beams were conducted to verify the effectiveness of the proposed method and the accuracy of the design algorithm.

Abstract:The lateral pressure of very earlyage concrete on the formwork directly affects the formwork design, whose numerical size is controlled by the casting rate, concrete mix，temperature, surface characteristics, size and shape of formwork and the depth of the casting concrete and so on. Therefore, the influencing mechanism is quite complicated. Based on theory analysis, a model test which can obtain the lateral pressure under the condition of different concrete mix was designed, and the measuring results were analyzed. The test results show that the vertical distribution of lateral pressure is similar to the hydrostatic pressure, but significantly less than the hydrostatic pressure. As the concrete watercement ratio increases, the initial template lateral pressure gets closer to the hydrostatic pressure, and the lateral pressure drops faster. The cancellation of lateral pressure occurs after the end of the dormant period of cement hydration. The accelerated rate of formation of hydrates enables the material to become selfbearing, which leads the rapid decrease of lateral interaction towards zero.

Abstract:In this paper, the driving simulator was used to realize the roadway scenario for Yongji freeway in Hunan Province, China. The driving scene was reproduced in virtual reality by the exact road design parameters and roadside elements from the design blueprint. The research objects are tangent + horizontal curve combined alignment and continuous horizontal curves combined alignment. The safety evaluation method was introduced based on the driving simulation data in terms of experimental design, data processing, indicator selection and model building. The results indicate that speed differential is positive correlated to the length of tangent segment and operating speed in the model of tangent + horizontal curve combined alignment, and it is also positive correlated to the length of the first horizontal curve and the ratio of curvature radius in the model of continuous horizontal curves combined alignment. The 50th/85th percentile values of the speed differentials are found as the safety thresholds of “GOOD”, “FAIR” and “POOR” according to their distribution.

Abstract:Based on the empirical data collected at six signalized intersections in Shanghai, a drivers’ stop/go decision behavior model was developed by using the risk homeostasis theory (RHT) and the utility theory (UT). The study shows that the drivers’ stop/go decision behavior is significantly affected by the time of the red light and is tradeoff between traffic conflict risk and time saving benefit. The ratio of timetointersection (TTI) and waiting time of red light (R) of passenger car drivers is approximately 180∶1. Truck drivers are more aggressive on stop/go behavior than passenger car drivers, while drivers in urban district are more aggressive than drivers in suburban district. Moreover, the probability of severe traffic conflict is significantly increased by aggressive driving behavior.

Abstract:A fuzzy neural network system was developed to improve urban expressway shortterm speed prediction accuracy on rainy days, taking fuzzy influencing factors such as traffic volume, occupancy and precipitation, as well as their nonlinear interaction into account. Based on the traffic flow and weather data of Shanghai, the best model structure was determined and its performance was evaluated against those of the existing autoregressive integrated moving average model, the back propagation neutral network, and the support vector machines model. The results show that the root mean square error and mean absolute percent error of the fuzzy neural network system are 3.05 km?h-1 and 3.95% respectively, which outperform those of the other three prediction models.

Abstract:Based on the previous work about verification problem projection according to the safety requirements, a variable reduction approach was proposed based on causal relation for the projected subproblems. First, the causal relations among the environment variables of the projected subproblems were defined. Then, the basic causal relation combination of variables and the reduction rules were concluded. Through variable reduction, the state space of the verification problem was reduced. Finally, with configuration of a domestic metro line, an experiment of modeling and verification was demonstrated to show that the variable reduction approach efficiently reduces the verification complexity.

Abstract:A dynamical interaction model of the ballasted track, subgrade and heavy haul train system was developed. The distribution of displacement of the heavy haul railway ballasted Tracksubgrade system under 30 t axle freight vehicle running are solved using the combination of the new rapid explicit integration method and the Newmark integration method. The results show that the dynamical displacement state of each structure layer of the tracksubgrade system is complex, and the load is in the cyclic loading and unloading during heavy haul vehicle passing. The amplitude of vertical dynamic displacement is the largest in three components of the displacement of the tracksubgrade system, while the amplitude of the lateral displacement and longitudinal displacement are less than 6% of the amplitude of the vertical dynamic displacement. The dynamic displacement distribution in lateral direction, of which the amplitude fluctuation is less than 0.2 mm, is relatively moderate and could be approximated as uniform distribution. The changes of the dynamic displacement of the tracksubgrade system in vertical direction could be divided into three phases: for the first part between the rail and the sleeper, the amplitude of dynamic displacement attenuates distinctly; for the second part, the amplitude of dynamic displacement attenuates gently in the sleeper region; and for the third part under the ballast bed, the amplitude of dynamic displacement attenuates continuously along the vertical direction, and the rate of attenuation is continuously decreasing with the increase of the depth.

Abstract:Determination of resilient coefficients of rubber material is essential to the design and optimization of elastomers in most engineering fields. Based on the nonlinear elasticity theory, a set of experiment including uniaxial tension, uniaxial compression and planar tension tests under large deformation was conducted and coefficients of a hyperelastic model were fitted. The testing data and corresponding simulation results can be used, on the one hand, to integrallty define the initial shear modulus, Young’s modulus, bulk modulus and apparent compressive modulus of present material, and on the other hand, to accurately predict the material nonlinearity and strong dependence of compressive modulus under different test conditions. Then a set of material mechanics experiment within small deformations was performed and the corresponding linear modulus were calculated. Finally, several conclusions about small and large material mechanics experiment as well as linear and nonlinear elastic theory were proposed through comparative analysis.

Abstract:To satisfy the safety properties of the organic anchorage adhesive used in engineering field after heating from elevated temperatures, a series of pullout tests for three anchorage adhesives were conducted after heating at temperatures of 25, 60, 100, 160 and 260 °C. The glass transition temperatures of three adhesives were tested. The heating process was found to follow a fixed curve. Three commonly used anchorage adhesives were adopted. The forceslip relationships of the adhesives after heating, the ultimate strengths and their change regulation with the temperature were obtained. A threestage or fourstage model for the forceslip relationship was obtained by curvefitting. The results show that the bond strength of anchorage adhesive is strongly dependent on temperature, and the rigid and heat tolerance of thermoplastic adhesive is weak than thermosetting adhesive. The results also show that glass transition temperature is the turning point for behaviors of adhesive after heating, which can be used to determine the upper limit temperature for continuous application.

Abstract:A monocoque chassis for racing car was designed with the carbon fiber and aluminum honeycomb as the main materials. Different materials were studied and chosen. The direction, sequence and thickness of each constituent layer were sequently optimized with freesize optimization, size optimization and shuffle optimization. The torsion strength and bending stiffness of the monocoque car body were mechanically and experimently checked. The results show that the mass of the body is 24.3 kg, which is 34% lower than the orignal steel frame, and the torsional stiffness of the designed carbon fiber monocoque car body can reach the same degree with the reference steel frame body. With optimized match of direction, the thickness and sequence of each layer, and carbon fiber composites products can provide more strength and stiffness than steel products.

Abstract:In order to study the new electric wheel vibration problems caused by torque ripple, the electric wheel vibrations under working conditions were measured in bench experiment, and order features and highfrequency characteristics of tire horizontal vibration were revealed. Based on analytical model of electromagnetic torque, and considering nonsinusoidal magnetic field distribution and current harmonics, torque ripple features were analyzed from the point of view of magnetic field interaction. Then, the order features of tire vibration were explained by source analysis of torque ripple. The 6th order vibration arises from nonsinusoidal magnetic field distribution while the first order vibration arises from current harmonics, and the 5.0th, 5.5th and 6.5th order vibrations arise from the interaction of nonsinusoidal magnetic field distribution and current harmonics. Based on the rigid ring tire assumption, the dynamics model of electric wheel system was established and modal analysis was conducted.

Abstract:The limit of drivers’ capacity of collision avoidance by braking and steering were analyzed in this paper based on the charateristics of drivers’ collision avoidance manervers and vehicle dynamics. The critical values of timetocollision(TTC) of these two different collision avoidance manervers were obtained and compared. The influences of road coefficient and overlap rate were also analyzed. The results quantitatively show that under certain conditions such as high relative speed, low friction coefficient, and small lateral overlap, the collision avoidance by steering is easier than by braking.

Abstract:The energy consumption of plugin hybrid electric vehicles (PHEVs) was simulated using forwardfacing stream of calculations, and the user influence factors of the economy of PHEVs were discussed. Then, the model of powertrain and longitudinal dynamics system of PHEVs were built based on Modelica language and utilized to simulate the fuel consumption of Chargesustaining (CS) mode and electric consumption of Chargedepleting (CD) mode under the standard driving cycle. Finally, the influencing mechanism of average driving speed and driving aggressiveness on CS fuel and CD electrical consumption was obtained by analyzing the energy consumption of each consuming component and the engine thermal efficiency.

Abstract:Aimed at the floating ring bearings(FRBs), the heat transferred between the inner film and outer film was calculated based on the floating ring balance model, the fluid lubrication model, and the heat dissipation model, which was considered as one of the conditions for lubrication analysis. The method to find the outer film eccentricity ratio without heat transfer through the floating ring was proposed. The lubrication performance of FRBs at different outer film eccentricity ratios and rotate speeds was analyzed. The results show that at different outer film eccentricity ratios, the heat transfer is totally different. There exists an outer film eccentricity ratio where there is no heat transfers between the inner film and outer film. The rotation speed affects the quantity of heat transfer between two films. As the rotate speed increases, the quantity of heat increare, too. The heat transfer has an effect on ring speed ratio. When considering the floating ring heat transfer, the temperature rise, the ring speed ratio, and the frictional power consumption change apparently.

Abstract:In this paper, an attempt was made to identify and optimize the rattle noise signals by relative approach based on the hearing characteristics of human ear. In the first step, the noise signals at the driver’s right ear were filtered by the transfer functions of the outer, middle and inner ear, and the steady noise signals were extracted by the regression and smoothing processes. In the second step, the gear rattle noise relative approaches were obtained by subtracting the steady noise signals from all of the filtered noise signals. The gear rattle noise relative approaches were the transient noise signals of the unloaded gear pairs which caused the gear rattle noise. In the last step, the occurrence time, frequency and level of the gear rattle noise were obtained from the relative approaches. The result of the gear rattle noise identification was consistent with that of the subjective perception and identified accurately. The rattle noise contribution of all the unloaded gear pairs was obtained by using the gear rattle noise relative approaches. The results show that the reverse gear pairs were the main source of the gear rattle noise. The rattle noise level was decreased by 17.4% with the backlash of the reverse gear pairs being reduced by about 50.0% by enhancing the gears process precision, and the rattle performance was effectively improved.

Abstract:Taking a hatchback car as the research object to optimize its aerodynamic performance on styling stage, this paper was devoted to improve the efficient of optimization and reduce the blindness in aerodynamic drag reduction and optimization. By applying morphing software, optimization software, and fluid analysis software, an automatic optimizing process was developed, which could optimize different variables and levels at the same time even when there are no people involved, and finally bring up the best drag reduction scheme in combination.

Abstract:The colored point clouds can be acquired by terrestrial light detection and ranging (LiDAR). The refined texture can be rapidly and automatically generated by colored point clouds. However, these original colored point clouds of different measurement stations have difference in colors which can lead to an unsatisfied display result of generated texture. According to the approximation between color components and spatial coordinate, a dodging based color coordinate conversion method was proposed for dodging the original colored point clouds. The proposed method was verified by experiments and the results show that the color variation of different measurement stations can be modified and a refined texture can be achieved. In addition to terrestrial LiDAR point clouds, this method can be applied to other kinds of terrestrial LiDAR point clouds with colors.

Abstract:The influence of wavelength and Fourier amplitude spectra of the body wave (P and SV wave), together with its interference surface waves (Rayleigh wave) on the the rocking components of earthquake motions was explored, and the synthetic formula of rocking components of earthquake motions was obtained. The dispersion curve of surface wave in given crustal model was obtained based on the elasticwavetheory and the fast δmatrix algorithm. Meanwhile the synthetic process of the rocking components of earthquake motions involving incident body and surface waves was explored based on Trifunac’s research. The Trifunac’s composite formula was modified to generate translational components of earthquake motions, relevant to earthquake magnitude M, epicentral distance R, and site condition s. Then rocking components of earthquake motions of a spot of ground surface were generated according to the differential frequency of body and surface waves, and corresponding tripartite response spectrum was given.

Abstract:A moderated mediation model was constructed, consisting of independent variable of project manager servant leadership, dependent variable of project performance, mediating variable of team affective commitment, and moderating variable of leadership team representative, to study the mechanism of project manager servant leadership on project performance. The study of 316 valid survey samples of 64 project teams indicates that project manager servant leadership has a positive impact on team affective commitment and project performance, Besides, team affective commitment has a full mediating effect on the relationship between project manager servant leadership and project performance. In addition, leadership team representative moderates the mediating role of team affective commitment on the relationship of project manager servant leadership and project performance.

Abstract:A model was built to test the effects of new type of urbanization on both rural and urban consumption in China considering the characterristics of the new economic normality, and an empirical research was conducted with the panel data of China’s provinces ranging from 2012 to 2014. It is found that under new economic normality, urbanization rather than urban consumption increases rural consumption. Moreover, the robust tests show that urbanization can improve rural consumption of both the coastal and inland provinces. Furthermore, it can also increase rural consumption of different income provinces. However, it has both positive and negative effects on rural and urban consumptions if adding lags.