Abstract:Passive control of stay cable using nonlinear friction damper was studied. A friction damper can provide higher additional damping to stay cable than that of a common linear viscous damper. The damping performance of a single degree of freedom system with a friction damper was investigated. The equation of motion of a taut cable with a coulomb friction damper was derived and was solved by using Galerkin formulation. The free vibration attenuation characteristics and the damping performance of the cable with a friction damper were theoretically and numerically investigated. The damping mechanism was discussed. A universal estimation curve was proposed that relates the modal damping ratio of a cable with a friction damper when the effect of various parameters on damping was considered. The results of numerical simulation were compared with those of the experiments, they are in good agreement. The value of a maximum available additional damping was analyzed. The results show that the maximum modal damping ratio of cable with a friction damper is not a fixed value, but a range, the lowest value of which is larger than that of an optimal passive linear viscous damper.

Abstract:The seismic action mechanism of the architectural glass curtain wall, including floor acceleration and inter story drift from main structure, was analyzed. Correspondently, a multi modal loading test method with shaking table was proposed to reproduce the multi dimensional seismic actions on the curtain wall simultaneously. To verify its validity and feasibility, an experiment, using a designed multi modal loading device, was conducted to study the seismic performance of zonal hanging glass curtain wall on a complex high rise building, which allowed for the synchronous realization of three direction dynamic acceleration time history actions, step by step loading of horizontal drifts and internal forces of steel sag rods. Finally, the hybrid simulation for the seismic performance of glass curtain walls was discussed.

Abstract:Based on the experimental results of the progressive collapse behavior of beam column structures, which had different structural details or were strengthened with different measures by glass fiber reinforced polymer (GFRP) sheets, numerical analysis on the progressive collapse behavior of reinforced concrete beam column structures was implemented by using commercial finite element software MSC. Marc. The calculated results agree well with the test ones, and the simulation method is proved to be effective and practical. This paper illustrates that the progressive collapse resistance of the reinforced concrete structures can be enhanced by the GFRP sheet strengthening.

Abstract:Tornado vortex simulator (TVS) in Tongji University was constructed to generate translating tornado like vortices for the physical simulation of tornado like vortex and quantifying tornado induced aerodynamic loads on structures. A controlled fan, an annular duct and turning vanes suspended from the overhead crane composed the main parts generating tornado like vortex, which could also be translated as a whole along a ground plane at the maximum speed of 0.4 m·s-1. The tornado like flows with swirl ratios ranging from 0.11 to 0.54 achieved by changing vane angle (θV=20°~60°) were simulated by the simulator and measured with TFI Cobra Probes. The flow structures of the vortices were validated by comparing with the mobile Doppler radar observations of three major tornados happened in Spencer, South Dakota May 30, 1998 and Mulhall, Oklahoma May 3, 1999 and Manchester, South Dakota June 24, 2003 respectively. The structures of the tangential velocity and the surface pressure of the simulated tornado like flow were found to agree well with the measured data of the tornados, indicating that this simulator could generate stable tornado like vortex and be used to simulate tornado like flow physically.

Abstract:A homogenization based two scale finite element method is developed to simulate compactions of visco plastic granular assemblies. The new method is used to develop macro constitutive relationships in light of microscopic behavior. At the microscopic level, governing equations for the motion and deformation of particles, including coupling of rigid body motion and deformation of deformable bodies, are investigated. And an implicit fine scale finite element model for granular media is developed to perform visco plastic analysis for the assemblies. At the global scale level, the homogenized standard continuum is analyzed using a coarse scale finite element model. To verify the accuracy and efficiency of the numerical method, a numerical example is simulated, and the results are in satisfactory agreement with the experimental results in the literature. This method can be used in a variety of problems that can be represented using granular media, such as asphalt, polymers, aluminum, snow, and food products.

Abstract:Starting from the governing equations of thermoelasticity for the plane strain problem, the analytical solution of the problem is obtained by using the Fourier transform and Laplace transform. And then, the exact stiffness matrix for the multi layered plane strain problem in stable temperature field is established, which is called analytical layer element. The global stiffness matrix is assembled by considering the boundary conditions and the continuity between adjacent layers, and the solution in the transform domain are obtained by solving the equations of the global stiffness matrix. The actual solutions in the physical domain are acquired by inverting the Laplace Fourier transform. Numerical calculation and analysis are carried out by corresponding computer program whose results agree well with those by finite element analysis software, and numerical calculation shows the layered characteristics has a significant effect on the thermal stress and vertical displacement in layered pavement system.

Abstract:As per the problem of loading stresses calculation for road and terminal concrete pavement of port areas under moving vehicle loads and container loads, the configurations of moving vehicle loads and container loads are simplified as single wheel (single container leg) load, single axle single wheel (two container legs) load as well as multiple axle single wheel (four container legs) load. An unequal planar dimension double layered pavement model is adopted, and a set of general loading stress formulas for road and terminal concrete pavement of port areas are put forward. The influences of the side wheel load, adjacent axle load, two and four container legs load, planar size of concrete pavement slab and base extension as well as joint load transfer capacity etc. on the loading stresses in concrete pavement slab and base are thoroughly analyzed. At last, a comparison of results based on the finite element method and obtained with formulas is made to verify the agreement and precision of loading stresses, therefore, the research resultants can be used for the loading stress calculation for road and terminal concrete pavement of port areas under moving vehicle loads and container leg loads.

Abstract:In order to enhance the operation efficiency of the bus rapid transit (BRT) system, the optimal layout of BRT stops at intersections was discussed. Theoretical models were established for estimating the delay and queue length at the end of the green time with the consideration of signal control delay, dwell time and the waiting time for boarding and alighting service. Two scenarios of BRT stop locations, near side and far side bus stops were taken into account. The models were tested by VISSIM simulation. Results of extensive numerical analysis show that the position of the BRT stop has no effect on delay when the volume of BRT vehicles is low and the bus stops should be disposed at the intersection approach when the volume is high.

Abstract:The computational fluid dynamics method was applied to an investigation of the influence of wheel width on vehicle aerodynamic performance for a general sedan car. After a comprehensive analysis and comparison of the changes in flow structure of isolated wheels and full scaled vehicle models with different wheel widths, the conclusion can be drown that the aerodynamic drag of isolated wheel decreases approximately by 9.2% while the aerodynamic drag of whole car model decreases by about 2% when the wheel width reduces by every 5%. This is due to the reason that the reduction of wheel width can effectively decrease the flow separation beside the wheel and then the vortex zone in the wake, besides, it can also lower the turbulence intensity in the rear ended area of the isolated wheel as well as the whole car model, which will help to reduce aerodynamic drag of the given models.

Abstract:An evaluation of the most frequenytly used five turbulence models on the flow around a simplified train model is presented. Based on numerical simulation and test results, a conclusion can be drawn that the most accurate prediction for drag is achieved by Realizable k ε, the minimum error is 2.5%, while shear stress transport(SST) k w is more accurate for lift, 0.5% is the minimum error. In addition, quasi two dimensional separation captured by Standard k w and SST k w approximates oil flow visualization, however, the three dimension separation is more exactly captured by Realizable k ε Model.

Abstract:The fluid structure interaction (FSI) effect was considered in the wind tunnel test and numerical simulation for the improved Ahmed body. The validity of numerical simulation method about FSI was confirmed with body displacement data which was measured by the scaled wind tunnel test. By experimental and numerical methods, the change regulation of aerodynamic force and moment was described when FSI was considered and the internal mechanism of the change of aerodynamic force and moment was revealed. It was concluded that the FSI effect should be considered in vehicle design.

Abstract:The calculation method of fluid structure interaction is used for finite element analysis of the high speed buses’ polyvinyl butyral(PVB) windshield, and the laws of the wind induced vibration characteristics of glass are obtained, also the relationships among the windshield thickness, deformation and stress are obtained. Research results show that the deformation increases significantly while the thickness decreases, but the stress changes irregularly. The results of this study can provide a theoretical scientific basis for the optimal design of the windshield of high speed buses and trains.

Abstract:An experimental study was made of the change characteristics of sensible cooling ratio of the residential temperature humidity independent control air conditioning. The experiment was made in the enthalpy potential laboratory and the parameters value of heat exchange medium that filled in two evaporators were remained unchanged. By changing the compressor speed and the refrigerant distribution ratio, the curves of cooling capacity, sensible cooling ratio SCR and the energy efficiency ratio EER could be obtained. The experimental results indicate that not only the total cooling capacity, but the ratio of the sensible and latent heat handling capacity can be changed. The range of SCR is from 0.6 to 1.0, which is much more than the traditional air conditioning. It means that it can match the room sensible heat ratio (SHR) and control the indoor thermal environment better. Meanwhile, SCR is restricted by the total cooling capacity and EER. For saving energy, EER should be maximized on the basis of the realization of the cooling capacity and SCR.

Abstract:The result data of the mid processing computation of vector form intrinsic finite element analysis has a large size. That is a considerable bottleneck in the speed of the Cloud uploads and program load, which should be highly compressed. The behavior data of the vector form intrinsic finite element is studied. After analyzing the characteristics of high redundancy, invalid data and numerical notation format of the data, a practical compression algorithm is proposed to merge the time information, delete redundant data, round the over precision and use the line element incremental expression. The numerical experiments indicate that, this algorithm highly compresses the behavior data size and accelerate the data load speed. It greatly improves the usage efficiency of the vector form intrinsic finite element behavior analysis software.

Abstract:This paper studies the equivalent reconstruction of the newly proposed skyline query using a group of existing skyline snapshots under the database cache model. We present a novel two phase algorithm for processing skyline query on cache model (APSQCM) to support this reconstruction. In the first phase, the APSQCM algorithm captures the inherent relationship between the newly proposed skyline query and the existing ones, and obtains all the skyline radixes which can be used to equivalently reconstruct the newly proposed skyline query. And in the second phase, the APSQCM algorithm produces the correct result of the newly proposed skyline query from the skyline radixes. Furthermore, we present detailed theoretical analyses and extensive experiments that demonstrate our method is both efficient and effective.

Abstract:In order to increase the power efficiency and operating reliability of cabled seafloor observatory networks (CSONs), the overall structure of the remote power monitoring and control system (PMACS) is designed according to the CSONs’ physical characteristics. The PMACS is divided to three subsystems, which are the data collection subsystem, the load management subsystem, and the network analysis subsystem. The functions and relations of these subsystems are introduced and the time synchronization scheme, load power optimization, and network analysis algorithms are studied. Through theoretical analysis, the weighted least square state estimation of the branching unit voltages is generated and a novel method for the ground fault location of the CSONs’ submarine cable is presented based on the controllability of power switching branching units. The study can be a reference to the construction of national CSONs in future.

Abstract:A least squares plane fitting of repeat tracks method was proposed to estimate the elevation changes of the Lambert Glacier Basin, East Antarctica. Using the latest ICESat (ice, cloud, and land elevation satellite) R633 version GLA12 altimetry products released by the National Snow and Ice Data Center (NSIDC), the elevation changes from 2003 to 2009 were estimated. The terrain slope should be considered when using altimeter repeat observation data determine surface elevation change. We assume that least squares plane fitting along track can separate both the slope of plane and elevation change rate, and consequently the elevation changes can be calculated. The results show that the average elevation rate of lambert glacier basin is (1±0.5) cm·yr-1 from 2003 to 2009, which is consistant with previous research results. The crossover point method was also used to verify the results, which proved that the repeat tracks plane fitting is an effective and feasible method.

Abstract:Slicing technology and morphological operators are employed to extract contour feature from scattered point cloud. Through slicing, unorganized point with high density can be transformed into point sets on a series of plane layers. Raster structure of digital image is utilized to organize sliced point cloud to generate binary images. Then morphological operators are employed to extract contour pixels. The contour pixels are transformed back to contour points, and B spline fitting is done to generate contour feature. The experiment results show that this method can produce high quality result and overcome the multi loop problem.

Abstract:We reprocess conventional gravity data with the method of correlation coefficient imaging of gravity parameters based on wavelet multi resolution technology. Solving correlation coefficients of different points of space characterizes the possibility of anomaly on ground generated by different points , so we can do the interpretation of gravity data from a plane space to a three dimensional space. Characterizing the abnormal distribution by gravity parameters correlation coefficient of different points, and making the contrastive analysis of processing results of the model profile data, we have found that correlation coefficient imaging based on wavelet multi resolution decomposition has higher horizontal and vertical resolution compared with correlation coefficient imaging without decomposition,. Finally, the paper puts forward the model 3d correlation coefficient imaging results, which agree well with model parameters. Imaging results based on this method can reflect more directly and clearly the space distribution and extension of the abnormal body.

Abstract:Following the idea of the quadratic inference function (QIF), a kernel quadratic function method for varying coefficient model with longitudinal data was proposed by using local polynomial smoothing method and approximating the working correlation with a serious of basic matrices in the generalized estimation equation. The asymptotic normality of the estimators of the coefficient functions was proved. This method improved the performance of the estimators by widening the bandwidth in order to plug in the correlation within subjects to the local area, which won’t lead to an “over fitting” phenomenon. An applied method was also proposed to choose QIF bandwidth in the simulation.

Abstract:It is studied how to solve the optimal control problem for a constrained linear system with a non convex cost functional. With Pontryagin’s maximum principle, a non convex quadratic programming is treated by a backward differential flow. Then the optimal control is obtained by solving a nonlinear differential boundary problem. An algorithm is given corresponding to the mathematical process. It follows by a numerical example.

Abstract:The speech transmission index (STI) and speech transmission index for public address system (STIPA) metrics at 12 receivers in 4 rooms, with a total of 48 acoustic conditions, were measured using the direct and indirect method and the measurement results of the two methods were compared, with a particular attention on the influence from the frequency response of the measurement system. The results show that, there is no substantial difference between STI and STIPA metrics; both direct and indirect measurement can be used as an objective rating method for speech intelligibility, as long as the standardised measurement program and measurement system are adopted.

Abstract:We know that investors of financial assets face many types of risks. The main ones are credit risk and liquidity risk. We set up models which are the valuation of credit and liquidity losses for measure of risk respectively. we provide the models which are the valuation of credit and liquidity losses respectively. And we also offer the pricing models of default financial securities with liquidity risk. In terms of liquidity of financial assets, influencing factors of liquidity include markets and its own characteristics. The study adopts the actual data of the financial markets and the loss of the model to an empirical analysis of the liquidity of the bond market.

Abstract:On the premise of outsourcing strategy, the process of selecting outsourcing service providers should be analyzed. By using the method of analytic hierarchy process(AHP), the performance measurement indexes of providers were divided into four parts, namely cooperating, service, just in time (JIT) and cost. These indexes should be quantized, so that corporates could evaluate the comprehensive providers’ performance by calculating the weight of indexes and their evaluation, thereby they could select the provider with the highest score. Finally, an applied case was given to show the feasibility of this method.

Abstract:As a third party, the project manager can be provided with three conflict management styles when dealing with employees’ conflicts, namely resolution, prudence, and avoidance. Based on a questionnaire survey completed by 394 members of a construction project team, a research model is established, taking lead member exchange(LMX) as the intermediate variable, the colleague experience and team type as the moderator. The conclusion shows that resolution and prudence are significantly positive interrelated with LMX, while avoidance is negative interrelated with LMX and can result in an increase in turnover intention. LMX acts partly as an intermediary role between the three conflict management styles and employee’s turnover intention, while the colleague experience will strengthen the influence imposed by the conflict management styles upon LMX.