Abstract:Based on the research of linear SDOF compound stochastic vibration and Monte Carlo simulation,non-linear improved stochastic perturbation method is adopted to solve single stochastic problem,and bi-linear SDOF stochastic structure is expanded to mean part and variation part.Then, the probability distribution type of stochastic response is assumed as normal distribution or uniform distribution. As a result,bi-linear compound stochastic differential equation is expanded to linear perturbation stochastic differential equations.Stochastic response is obtained with the pseudo excitation method and iteration.A case study shows that the combination of non-linear improved stochastic perturbation method with pseudo excitation method can get relatively accurate result of stochastic response of non-linear compound stochastic vibration system.For more accurate results,precise pre-estimate of the probability distribution type of stochastic response is very important.

Abstract:An analysis was made of the integrated process and characteristics of building information modeling(BIM) data model.The complexity of the modeling and repetitiveness of the information conversion owing to different disciplines were illustrated by various representation of building components.Based on the research,an integrated framework system,namely architectural and structural information model(ASIM),was presented for facilitating collaborative design between architects and structural engineers.The ASIM system is capable of transforming data information from architectural model to structural model by developing an information conversion platform,and has the expansibility,compatibility,phase and other characteristics.The system provides some technical supports for development of the next generation building software based on BIM.

Abstract:Mechanical properties of three kinds of 84 steel bars (HRB335, HRB400, and HRBF400) were studied through tests under low temperature ranging from -180℃ to -80℃.Tensile specimens were prepared according to national code of GB/T 3239—2006.Through tensile tests,the mechanical behaviors of these rebars under low temperature were studied.Analysis of the test results reveals that the shape of the stress-strain curve and the ultimate strain for steel bars may not be changed by the temperature，but the yield plateau,the yield strength,the ultimate strength,and the hardening strain of steel bars will increase with the decrease of the temperature.Based on the test results,regression equations of the characteristic values reflecting mechanical properties of rebars in super-low temperature environment were established,and then the stress-strain relationship of steel bars at super-low temperature was proposed.

Abstract:Based on well-regulated two dimension tensile stress regions at the back of anchorage structures of prestressed concrete bridges,a new method on reinforcement design named “tensile stress region method” is advanced for the lack of reinforcement theories.The blocks can be divided into several tensile stress region slices,then the web reinforcement is raised up to bear the tensile stress orthonormal value for each,and the notion “tensile stress region slice depth” is advanced to control the longitudinal length of reinforcement.An example of external prestressed anchorage reinforcement is analyzed by means of tensile stress region method,thus a finite element model is built up.In addition,the influences of transverse,vertical prestressing are also taken into consideration.The results show that the reinforcement amount is affected obviously by the transverse,vertical prestressing at the anchorages when the tensile stress region method is used,this method can set steel bars according to the stress state,and more exact reinforcement results can be obtained.

Abstract:The wind tunnel tests on rigid models of saddle-shape cable roofs with and without enclosed wall were carried out in exposure categories B and D. The distribution characteristics of the fluctuating wind pressures in the two wind fields and their relationships were investigated based on the wind pressure data obtained from the tests. Besides,the influences of the enclosed walls on fluctuating wind pressure distribution characteristics were also discussed in detail by comparing the power spectra and time series of wind pressures on the saddle roof model with and without the enclosed walls. The results indicate that the wind field category has significant effects on the fluctuating wind coefficients;the fluctuating wind distribution characteristics are similar to mean wind pressure distribution;the fluctuating wind pressure energy of saddle-shape cable roof with enclosed wall mainly distributes in the reduced frequency range lower than 0.3 Hz,but fluctuating wind pressure energy in high frequency range of saddle-shape cable roof without enclosed wall is higher than that of saddle-shape with enclosed wall.

Abstract:In order to determine exact wind loads of the blades and the tower,wind field simulation of wind turbine systems is investigated.Based on the random function description of stochastic processes,the crossrotational Fourier spectrum based on the physical mechanism is proposed to consider the rotating effect and the correlation of two different wind velocities on the blades.Then,wind velocities on blades (or the tower) are generated through the inverse Fourier transformation of the rotational Fourier spectrum (or the random Fourier spectrum).Finally,an example involving simulation of longitudinal turbulent wind field of a 1.25MW wind turbine system is investigated.The result shows that the proposed algorithm is of high accuracy.

Abstract:Based on experimental results and simulations with software Fluent,the interactions between seepage and tangential flow were investigated,and the results of experiments and simulations agreed well.Results show that the flow obviously affects the seepage in the sand soil.For the same tangential flow,the pressure fields and streamlines change with the seepage velocity,and the seepage conductivity increases with the increasing seepage velocity.

Abstract:For investigating the thermal stresses in reinforced concrete structures under the non-linear temperature gradient,an analytical procedure of space structures was presented with the aid of the user-programmable features of ANSYS based on the relaxation-method and the gird-method in sectional analysis.Reinforcing and cracking were also taken into account.In order to study the thermal stresses of the Shanghai south railway station,the temperature variations in the annular girders were measured on site.A simplified formula was proposed to calculate the temperature gradient based on the surveyed data.The forementioned procedure was used to analyze the thermal effect of the main structure.The analytical results show that the temperature load due to solar radiation has a remarkable effect on the concrete structures.

Abstract:An exponential curve model is modified for load transfer function,and matrix displacement method programmed by MATLAB language is used to the analysis of load transfer of pile. With different parameters of pile and soil as well as loading conditions,simulation analysis is made of the influence by changing the parameters of pile on load transfer mechanism of pile.Results show that the major load is transferred by the pile side and the rest is shared by pile tip when the length-diameter ratio is larger.When only enhancing the pile stiffness or increasing the length-diameter ratio,no remarkable improvement appears in the proportion shared by tip and bearing capacity of pile.

Abstract:To investigate the different effectiveness between dredger fill and natural soft soil in the cement-mixed improvement processes of an engineering case,two kinds of micro-experiments on dredger fill and natural soft soil before and after cement-mixed processes were carried out by using X-ray diffraction(XRD)and scanning electron microscope(SEM)tests in the view of chemical and physical microstructures.It is found that the physical microstructures have an important effect on the reinforcement performance of cement-mixed soils.Although the chemical reactions of cement-mixed processes are similar in both dredger fill and nature soft soil,there are significant differences in the microstructures of treated soils,which can affect the macro-scale strength directly.Therefore,in order to optimize the improvement in soft ground engineering,proper construction measures should be taken to improve the microstructures and mechanical properties of the dredger fill.

Abstract:With field monitoring and laboratory GDS test and mercury intrusion test,a quantitative study was conducted on the microstructure of the reinforced soft clay around the tunnel near the Hailun Road Station of Shanghai Metro Line 4.The fractal dimension was calculated by the thermodynamic model,and the relationship between the fractal dimension and the vibrational load was analyzed,and the variation law of residual strain with fractal dimension was obtained.

Abstract:The problem of phase sequencing with the objective of minimizing lost time was modeled based on mixed traffic characteristics.The matrixes of intergreen time,phase sequence,maximum intergreen time and sum of intergreen time were built and the mathematical relationship between matrixes was modeled based on signal groups including motor traffic signal groups (VG),pedestrian and bicycle signal groups (PG).The phase sequence optimization model was built based on the proposed matrixes and four kinds of objectives were considered:minimum total lost time of VG;lost time of VG;minimum total lost time of VG and PG,maximum lost time of VG and PG.A case study of a signalized four-stage intersection of Zhangjiagang City validated the model.The results show that the lost time of intersection paries with different phase sequences.The PG dramatically affects the optimal phase sequence.The proposed model can output optimal solution of phase sequence based on different objectives with the consideration of mixed traffic characteristics.The intergreen modules under different objectives were analyzed and the signal group-based intergreen design method was proposed to minimize lost time of intersection.

Abstract:Based on the uncertainty measurement theory,a safe grade-assessment and order-arrangement model of high-grade highway was established.First,the main factors influencing the safety of high-grade highway were taken into account to construct evaluation index system and appraisal criterion,and then uncertainty measurement functions for the main indexes were achieved according to the field data.Information Entropy theory was adopted to calculate the weight coefficients of these influencing factors,and then safe assessment grade was determined by credible degree recognition criteria.Finally,the results of safety evaluation for high-grade highway were obtained.The evaluation method can not only solve many uncertainty problems affected by various factors in highway safe aspect,but also can rank the order of safe degree.This method was adopted to evaluate safety level of four high-grade highways in Xinjiang Uygur Autonomous Region of China.Compared with the results of fuzzy synthetic evaluation method,the study results show that uncertainty measurement method is reasonable and can be applied to the actual engineering.

Abstract:In order to better describe the fuzzy and uncertain characteristics of drivers when following a leading car on the freeway,the adaptive neuro-fuzzy inference system(ANFIS) was applied to the car-following model.Firstly,the real-time car-following data collected by the five-wheel system were denoised by the wavelet tool in order to eliminate the disturbance from the surrounding and recover the initial information of data.Meanwhile,the driver’s reaction time was caculated by the correlation function in term of signal processing method.Then,the car-following model based on ANFIS was developed with the relative speed,distance headway between leading vehicle and following vehicle and speed of following vehicle as inputs and car-following acceleration as the output.Finally,the model that generated the adaptive rule of drivers’ car-following behavior was simulated and trained to compare with General Motors based car-following models.The car-following model based on ANFIS proves to be able to reflect the driving behavior of real freeway situaton.

Abstract:Based on single-factor analysis,rutting test and immersion rutting test were made to study the influencing factors on high-temperature performance of asphalt rubber(AR) mixture.Test results show that crumb rubber modifier (CRM) source,CRM content,asphalt content and air voids have great influence on high-temperature performance of AR mixture,while the effect of base asphalt and CRM size/gradation on high-temperature performance is not so obvious.Though the rutting test results under different aggregate gradations do not show much variation,the gap gradation with less mineral filler and less fine aggregate performs better in immersion rutting test,thus the gap gradation with less mineral filler is suitable for application in asphalt rubber mixture.

Abstract:The selective inhibition mechanisms of various pretreatment methods like heat-,acid-,alkali-,chemical inhibitor-,aerate-,as well as the load shock pretreatment are reviewed and their corresponding bio-hydrogen performance are compared and discussed.The disagreement in optimal pretreatment methods should be attributable to the difference in the tested seed sludge,kinds and concentration of substrate,temperature,pH and reactor type.In addition,pure substrates of glucose or sucrose are currently used as substrate for hydrogen production in many studies.Practical organic wastes are recommended to be used as substrate for comparison of the effectiveness of different pretreatment methods.

Abstract:The effect of initial pH(4.0~10.0) on thermophilic fermentative hydrogen production from cassava ethanol wastewater was investigated in batch experiments.Results show maximum hydrogen product (383 mL) is obtained at initial pH 6.0 and the corresponding hydrogen yield is 70 mL·g-1.The total amount of VFA /ethanol and the proportion of acetic acid in the VFA increase with the increase of pH.The distribution of aqueous products is always dominated by butyrate.The heat-pretreatment at 90℃ for 1h cannot completely inhibit the activities of methanogenic bacteria and homoacetogenic bacteria.Hydrogen consumption at different degrees was observed at initial pH 6.0~10.0,and methane was detected at initial pH 9.0~10.0 during the fermentative process.The degradation of substrates in cassava ethanol wastewater and fermentative products further demonstrate that the hydrogen is generated from the production of butyrate,resulted from the carbohydrate degradation.

Abstract:A comparative study of the electrochemical corrosion behavior of Fe78Si13B9 and Fe73.5Si13.5B9Nb3Cu1 amorphous and nanocrystallized alloys was performed with linear polarization method and electrochemical impedance spectroscopy in 1 mol·L-1 H2SO4 solutions.The amorphous ribbons and their crystallization processes were identified by differential scanning calorimeter (DSC) and X-ray diffraction (XRD).The photographs of the samples after potentiodynamic polarization were observed by scanning electron microscope (SEM).The influence of heat treatment on the alloy structure and corrosion resistance in 1 mol·L-1 H2SO4 solutions was investigated.The results show that nanocrystalline alloys have a higher corrosion resistance than amorphous talloys，and the corrosion resistance of amorphous alloys increases as thermal treatment temperature rises with nanocrystallized decreasing.

Abstract:A new type of photosensitive hybrid films based on poly (3-hexylthiophene) (P3HT) and multiwall carbon nanotubes (MWCNTs)was effectively developed,with P3HT as electron donor and the MWCNTs as electron acceptor.The resulting P3HT were characterized and investigated by 1H NMR,FTIR,UV-Vis and TEM.The solubility of polythiophene materials was greatly improved with the introduction of hexyl group.And the MWCNTs were chemically modified to improve its compatibility with P3HT.The UV-Vis spectra show that the conjugate effect of P3HT film is relatively higher than its solution.The conjugate effect in the P3HT film increases as its amount of oxidants increasing.The results show that the red-shift phenomenon of P3HT-MWCNTs hybrid films occurs as its MWCNTs content increases,and the solar energy usage improves with the P3HT-MWCNTs hybrid films than pure P3HT film.

Abstract:Digital image processing was used to measure the characteristics of particle group of lightweight aggregate,and multiple parameters were adapted to characterize the characteristic sizes.The effect of characteristics of particle group of lightweight aggregates on mechanical properties of lightweight concrete was then analyzed with grey correlation analysis method.Lightweight concrete of both high compressive strength and high flexural strength could be made with lightweight aggregates of specific surface area higher than 520 m2·m-3 and aspect of particle group lower than 1.34 as well.The results provide a scientific basis for choosing lightweight aggregates when making lightweight concrete.

Abstract:A pressure-time recession method to measure the gas permeability of the pipe-concrete interface in Plastic-Pipe confined Concrete (PPC) was introduced,and then effects of some improving measures on the gas permeability of the pipe-concrete interface in PPC were investigated by this method.Results indicate that this method is of high repeatability and stability.The gas permeability decreases with the increase of the expansive agent.The Preprufe tape greatly improves the bonding property of the pipe-concrete interface,and therefore,the decay time of gas pressure or the gas impermeability is an order of magnitude higher than that of the controlling PPC.Fitting curves of the gas pressure-time recession were conducted and an empirical formula was proposed.

Abstract:A test was conducted to examine the vehicle interior noise,windscreen vibration and wiper blade vibration induced by wiper friction,under combination conditions with various wiping speed and windscreen wetness.The time-frequency noise characteristics,influence factors and noise source were approached by means of time domain,frequency domain and time-frequency domain analysis.The results indicate that wiper noise can be classified into reversal noise and wiping noise.The reversal noise is characterized by impulsive noise,and wiping noise is featured by wide-band noise with harmonic signals.The nature of both types of noises is strongly affected by the degree of windshield glass wetness,while it is far less affected by the wiping speed.The wiping noise is mainly resulted from lateral and vertical vibration of wiper blades.However,the wiping noise under rain and half-dry conditions is respectively caused by the vibration of driver side and co-driver side wiper blade.

Abstract:The working principle of seal was analyzed and mathematical models of seal and its venting holes were set up by the application of mass and momentum balance equations.Seal consumption energy was calculated and man-machine interface was designed based on software Excel,VBA language,numerical and iterative methods.Through studying consumption energy of seal venting holes,consumption energy of seal venting holes damping force is 20% of seal total consumption energy.So consumption energy of seal venting holes is important influencing factors of seal total consumption energy.The calculation results are compared with the test data in different models that error less than 12% proves the calculation effectiveness.

Abstract:Software AVL-Fire was used to create the dynamic meshes of intake port and cylinder flow area of gasoline engine,in the strokes of intake,compression and expansion.The three-dimensional numerical simulation calculation was processed,and through the analysis of the distribution of air velocity,turbulent kinetic energy,temperature and pressure under different valve strokes,a more detailed flow field information was obtained,which provides a theoretical basis and reference to the design of the gasoline engine.

Abstract:An analysis was made for a parallel hybrid excavator system with ultra capacitor and ISG (Integrated Starter Generator) as auxiliary electrical power source and characterized by motor-driven slewing mechanism.A dual-mode engine torque balancing control strategy was proposed,and the load condition and the SOC(state of charge) of ultra capacitor were employed as decision-making basis to adapt the engine operating point.At a specific point,the torque balancing control strategy was adopted instead of the traditional speed sensing control,thus the system could be more stable. ISG motor can balance the engine torque to make it work in high efficiency area.In addition,the slewing mechanism-driven motor can recycle Potential energy.A simulink simulation model of the parallel hybrid excavator system was set up.Results show that the control strategy is suitable for parallel hybrid power system excavator with significant energy saving.

Abstract:With the goal to achieve the behavior semantic model of product,an analysis was made of the method of describing functional expression,as well as the behavior semantic.Based on the reasonable disassembly of function,along with geometrical character,a new describing scheme for product was described.Combining with XML and semantic network,we get the legible and concrete way to describe product function.Through a profound research with the constitution of functional matrix and the way of using FTML to describe semantic network,we design the algorithm of conversion between FTML and function matrix.On the basis of the research,a new way of case-based reasoning and evolution design is obtained.

Abstract:Based on principal-agent theory,this paper presents a study of the problem of quality control strategy in supply chain under the condition of moral hazard.We set up the expected revenue function of suppliers and buyers to design the qucontract in the following three cases such as the single moral hazard on the part of the supplier(quality prevention probability concealed) and the single moral hazard on the part of the buyer (quality inspection probability concealed),and double moral hazard (both quality prevention probability and quality inspection probability concealed).According to the optimization theory,the supplier’s and buyer’s moral hazard values were solved.A quantitative description of the information rents was presented and a simulation test was made.The simulation results show that when there is a single moral hazard on the part of the supplier,the buyer’s information rents and expected revenues will reduce,supplier’s expected revenues will increase; when there is a single moral hazard on the part of the buyer,the supplier’s information rents and expected revenues will reduce,buyer’s expected revenues will increase; when there is a double moral hazard,the information rents of supplier chain are the sum of supplier’s and buyer’s information rents in single moral hazard,the loss of the jointed expected revenues of the supply chain will be maximum.

Abstract:In a two-asset world a continuous time stochastic dynamic programming model,which involves constant contributions before retirement and constant expense after retirement,is set up to find the optimal investment strategy for defined contributions occupational pension schemes in which the employees with exponential utility function make decisions by themselves.It’s found that the optimal proportion invested in risky asset depends on the speed of pension assets and the risk-free rate.And the proportion decreases with time if the speed of pension assets is higher while the proportion increases if it is lower.In particular,the proportion will be stable if there is the same speed.Furthermore,the proportion decreases with the contribution and increases with the expense.The massive Monte Carlo simulations prove that.