Abstract:The static pushover analysis (SPA) procedure has been widely applied to the estimate of the nonlinear seismic performance of the multistory structure subjected to horizontal earthquakes. However, SPA could hardly obtain a satisfying result in accuracy when applied to the evaluation of seismic responses of the largespan latticed arch under vertical earthquake ground motions, whose lateral and vertical displacements were coupled. Accordingly, an improved modal pushover analysis (IMPA) procedure was proposed, based on the eigenstiffness, introduced from the static stability analysis of structures. Firstly, equivalent single degree of freedom (ESDOF) system was established based on eigenstiffness by modal pushover analysis for each mode selected. Secondly, the seismic responses of the ESDOFs were solved respectively and combined. Finally, the seismic responses of the structure were obtained by pushover analysis once more according to the load formula derived. The seismic responses of a latticed arch under a series of vertical earthquake waves on firm and soft sites, were obtained by IMPA. Compared with the results given by response history analysis, the node vertical displacements and the most unfavorable stresses of the arch were consistent in distribution, with errors about 10.5% and 33.2% respectively, and 25% computing consumption. Along with the increase in the number of the vertical modes selected of the arch, the accuracy of IMPA could improve.

Abstract:A static experiment test and finite element numerical simulation method were carried out to investigate the failure modes and bending performance of multiplanar steel tubular connection with annular ribbed plate. Local axial buckling and transverse plastic deformation failures on such connections were observed from these studies. The local buckling depended on the stress on the chord and the plastic deformation was related to the annular ribbed platetochord model comprised by the annular ribbed plate and a section of chord. For the two failure modes, plastic theory, finite element parametric study and regression analysis were used to develop the proposed formulas of ultimate bending moments for such connections. The proposed formulas were compared with that from experimentations and the results show that the formulas have practical significance and could provide references for the design of similar connections.

Abstract:In order to study the aseismic performance of the precast column connected with the new type of slurry anchor connection, a cast-in-place columns and two prefabricated column specimens, in which longitudinal reinforcement were connected by type I and III grouted sleeve lapping connector respectively, were designed for quasi-static test on the basis of the type I and III sleeve joint connection. The test phenomena show that the initial horizontal cracks of the cast-in-place column appear at the root. Because the vertical strain of the concrete is restrained by the sleeve, the initial horizontal cracks of the precast column appear on the top of the sleeve. In the limit state, the crushed part of the cast-in-place columns is long and the crushed part of the precast columns is short. The test results show that the cracking load and yield load of the precast column are slightly larger than the cast-in-place column, and the ultimate load of the precast column is higher. The cracking load, yield load of the two different types are almost the same, but the displacement under the ultimate load, ultimate displacement and ductility coefficient of the precast column are larger. Due to the stirrup encryption in the range of the sleeve of the precast column, the energy dissipation of the precast column is slightly better than the cast-in-place column. The strain of steel bar on the upper and lower parts of type I and type III sleeve is basically the same, so both of them can perform well in transferring the stress.

Abstract:To investigate the seismic performance of reinforced concrete (RC) frames after high temperature, two strong-beam-weak-column frames and two strong-column-weak-beam frames were designed. Two of the frames were subjected to fire test, then low-frequency cyclic loading tests were conducted for all the specimens. The variation of failure modes, bearing capacities, load-displacement relationship, deformability, stiffness, and energy dissipation as the endured greatest temperature and the beam-column size relation was analyzed. The test results show that the bearing capacities and energy dissipation capacities of the RC frames were reduced after fire, and the reduction of those of the strong-beam-weak-column frames was more serious. The yield displacement increased and the ultimate displacement decreased. After fire, the plastic hinge first occurred at the bottom of the column, then the beam end, and then the top of the column, which indicates the plastic hinge tended to appear at the column ends. The RC frames designed according to strong-column-weak-beam criterion (in which plastic hinges first appear at the beam-ends) may fail in the form of strong-beam-weak-column after fire.

Abstract:Based on the beach nourishment project between the Yanghe Estuary and the Daihe Estuary, the numerical simulation method is adopted to study wave-current coupled hydrodynamic responses to artificial island and beach nourishment projects. It can be found that changes in tidal current caused by the combination of artificial island and beach nourishment projects are not linear superposition of differences induced by artificial island project and beach nourishment project respectively, however, the changes in wave field have a linear superposition relationship. Reserving tidal channel in beach nourishment project is necessary for good water exchange, which benefits alleviating its influence to surrounding environment. The findings can provide a reference for beach nourishment under similar conditions.

Abstract:The Nested Logit Model was used to analyze the questionnaire investigation based on users’ travel modes choices. The factors influencing on users’ travel modes choices were researched. Users’ selection probability and sensitivity of travel modes were computed. The results show that cost, station distance, trip distance, driving-age, ownership of private cars and users’ age make a difference on selection probability of electric car sharing. Selection probability of electric car sharing based on RP(revealed preference) data is 2.36% while based on SP(stated preference) data is 3.30%. If cost of electric car sharing increase 1 yuan/kilometer, based on RP data selection probability of electric car sharing will decrease by 8.6% while based on SP data decrease by 8.9%. If station distance of electric car sharing increase 1 kilometer, based on RP data selection probability of electric car sharing will decrease by 43.7% while based on SP data decrease by 21.1%.

Abstract:The route choice set plays an important role in estimating passenger route choice and consequently calculating passenger flow distribution on an urban rail transit (URT) network. In terms of the problem of the route choice set in the existing assignment model and the cluster characteristics of actual travel times of URT passengers, a URT route choice set validation method based on travel time cluster analysis was proposed. It was developed on the basis of RodriguezLaio cluster algorithm. Taking the Beijing subway network for example, it is found that the proposed method can make rapid identification and rolling validation for abnormal OD on the whole network level, and provide important references for the passenger flow survey of causeanalysis oriented as well as model modification.

Abstract:For the fact of the modern tram’s potential safety risks in different environments, we proposed a millimeter-wave radar as the optimized method for modern tram obstacles detection and designed auxiliary safety protection function. Then, a new auxiliary safety protection algorithm was established. A modern tram auxiliary safety protection technology based on obstacles detection was also proposed with the information of anterior obstacles by the detector, and the location of obstacles and relative location of tram rail by coordinate matching. For the obstacles in the range of tram rail, this research could calculate the distance between tram and obstacles and compute train protection curve dynamically, therefore, the warning information could be delievered to the driver. Finally, the results of simulation experiments proved the research, which could provide the dynamic protection information based on the detective data. Key words： tram; obstacle detection; auxiliary safety protection; train protection algorithm

Abstract:A numerical prediction model was established for wheel wear development of heavy-haul vehicle under complex operating conditions, and the corresponding calculating program was written. According to Archard’s material wear theory, the wear distributions were calculated based on the vehicle-track dynamics simulation and wheelrail rolling contact analysis. Simulations were made respectively for every possible case and weight factors were introduced, in order to model the complex operating conditions. An adaptive step algorithm was adopted to update the wheel profile, which could improve the stability and reliability of numerical model. The wheel wear developing processes of heavy haul vehicle of Da-Qin railway under actual operating conditions were predicted based on the established model. The results show that the wear grows continuously with running distance increasing for every wheel, but the wear development shows a slowdown trend. The wear is mainly distributed in the contact area near nominal rolling circle, and the distribution range is wider for guiding wheel. The wear develops faster near the flange, which is more obvious for guiding wheel. The calculated results verified the rationality of the established model.

Abstract:Micro-polluted water was treated by micro-coagulation filtration with metallic membranes. The operation and fouling mechanism of micro-coagulation filtration with metallic membranes were investigated by electronic differential system(EDS), scanning transmission electro (SEM) and membrane fouling model. The highest removal rates in turbidity, UV254 and CODMn were 97.4%、80.9% and 64.6% respectively by using 0.3 μm metallic film. The specific flux (S) was increased gradually from 44.44 L?(m2?h?kPa)-1 to 58.33 L?(m2?h?kPa)-1 with constant flux operation and S was decreased from 47.91 L?(m2?h?kPa)-1 to 17.63 L?(m2?h?kPa)-1 with constant pressure operation. The result shows S of constant flux operation is higher than that of the constant pressure operation, indicating lower membrane fouling in constant flux operation. O, Al and Si increase obviously in polluted metallic membrane, suggesting that the main component of the contaminant may be aluminum silicate. The main fouling is cake layer pollution in metallic membrane by SEM and fouling model.

Abstract:Porous zeolite particles were prepared by adding adhensive and pore former with modified zeolite powder as raw material. The type and addition of adhensive, type and addition of pore-forming agent, water addition on the loss efficiency of the zeolite particle and the effect of the adsorption of nitrogen and phosphorus were focused on. The results show that polyvinyl alcohol (PVA) was better than cement and sodium carboxymethyl cellulose. The effect of sodiumon bicarbonate was better than that of activated carbon, and the micro-morphology of the porous zeolite particles were observed by scanning electron microscopy (SEM) and the results showed that the pore diameter and pore structure of the zeolite particles were significantly improved after adding sodium bicarbonate. The loss efficiency of porous zeolite particles at 0 was made by adding in the modified zeolite powder 1.2% PVA, 4% sodium bicarbonate, 40% water. The results showed a high adsorption of nitrogen and phosphorus, and the removal efficiency of nitrogen and that of the phosphorus in wastewater were 88.55% and 83.11% respectively. The adsorption kinetic of nitrogen, phosphorus on porous zeolite particles was following the pseudo-second-order.

Abstract:In order to reduce the economic cost effectively and maximize the effect of low-impact development technology in the low-impact development technology design, the total cost of low impact development program is taken as the objective function of economic judgment, and with the volume capture ratio of annual rainfall as the control target, the area of low-impact development as a constraint, the multi-objective optimization mathematical model of low-impact development was established, and the non-dominated sorting genetic algorithms-Ⅱ(NSGA-Ⅱ) was used to solve the multi-objective mathematical model analysis. Finally, a case study was made of a low-impact development project and the Pareto optimal curves of the total cost and the volume capture ratio of annual rainfall was obtained, which could provide decision-makers with multiple sets of different optimization schemes. The combination of low-impact development technologies was more scientific for a clear and reasonable decision-making.

Abstract:A forward simulation model of a fuel cell bus was established based on ADVISOR. A fuzzy energy management strategy was also formulated. In order to improve the fuel cell durability, an improved fuzzy control energy management strategy was proposed. The simulation results under the typical urban operating conditions in China show that the proposed energy management strategy is better than the traditional power-following energy management strategy in terms of vehicle economy and fuel cell durability.

Abstract:In terms of complex physical and chemical phenomenon of proton exchange membrane fuel cell (PEMFC) in cold start, a novel numerical model of PEMFC in cold start was developed. The model comprehensively considered electrochemical reaction, thermal and water and phase change mechanism in cold start. Three factors, ionomer volume fraction in catalyst layer, porosity and membrane thickness, were investigated. The indicator of water storage capacity(WSC) was finally introduced to evaluate the cold start capability of PEMFC.

Abstract:Compared with the published data, the validity of the large eddy simulation method is verified. The large eddy simulation method is applied to the study of the flow field around slanted surface and rear vertical base of the Ahmed body with a slant angle of 25°at high Reynolds number. This work aims to gain a relatively thorough understanding of the transient features of the predominant coherent structures around the Ahmed body by sampling flow field information and spectrum analyses of a recirculation bubble over the slanted surface, one pair of counter-rotating longitudinal C-pillar vortices originating from the two side edges of the rear window, and a recirculation torus behind the vertical base. In different regions of flow field, the transient features of the wake are different. The flapping motion of the recirculation bubble over the slanted surface corresponds to an absolute unsteadiness while the activity of the coherent structures is convective. The pair of C-pillar vortices coupled with the spanwise vortices over the slanted surface are symmetric. However, they only mix with the recirculation torus behind the vertical base resulting in asymmetric characteristic. The rolling up and shedding of the recirculation torus behind the vertical base are similar to Karman vortex street. At high Reynolds numbers, the characteristic frequency of different regions tends to be consistent.

Abstract:Establishing aerodynamic noise prediction method for high-speed train head helps to quickly obtain the aerodynamic noise characteristics produced by the interaction between the head and airflow. For this purpose, the aerodynamic noise simulation model of 1∶8 contraction ratio of three connected vehicle was established. The large eddy simulation was used to obtain the body turbulent fluctuation pressure. Based on the FW-H equation and the acoustic perturbation equation, far-field noise and near-field noise were respectively obtained. Then a set of prediction methods for aerodynamic noise were established. The difference between the simulation results of the total sound pressure level in the far field measuring point and the wind tunnel test was less than 2.0 dB(A). Their spectrum change trends were the same, and the magnitudes were relatively small, indicating the feasibility of obtaining far-field noise based on the FW-H equation. Based on the acoustic perturbation equation, the total sound pressure level of the key parts of the head region could be obtained. Comparison of the magnitudes showed that the total sound pressure level of the bogie was far greater than that of other parts. And this was consistent with the microphone array recognition results. So the near-field noise result obtained from the acoustic perturbation equation was verified. By comparing the turbulent pulsation total pressure level and the total sound pressure level in the different parts of the head type, it was found that the level of the bogie and the obstacle protector were greater than that of the window, nose cones and body. Compared with the total pressure level of turbulent pulsation, the total sound pressure level distribution was of a better uniform and the magnitude was smaller.

Abstract:This paper proposes an improved failure mode and effects analysis(FMEA) method based on hesitant fuzzy sets and grey relational theory for supplier risk assessment. First, the potential risks of suppliers were identified and then experts evaluated these risks using hesitation fuzzy linguistic terms on the basis of their preferences. Next, the sematic-based computation method and the rough set idea were used to translate the assessment information into intervalvalued numbers. Finally, it considered the relative importance of O, S, D when using grey relational theory to determine the risk priority. The case study shows that the method could help companies identify the main risks of cooperating suppliers, as well as provide support for managers to formulate risk management and control strategies.

Abstract:To solve the material supply problem for aircraft moving assembly line, an integrated model was formulated to make decisions of material delivery and container pickup, and the scheduling method was proposed to solve the model. On the basis of the material-batching and vehicle scheduling problems, decisions on the pickup of line-side containers were introduced. An integrating mathematical model with the objective of minimizing the number of deliveries was established and a heuristic algorithm based on genetic algorithm was proposed. Due to the global searching advantage of genetic algorithm, an improved heuristic algorithm was introduced to make a joint decision on three variables of the batching of job’s material and container, and delivery time, which took into account of the capacity of the delivery and line-side storage, and combined with the local search algorithm for re-optimization. Results of the numerical experiments proved the model and algorithms.

Abstract:This paper presents a simple and U-shaped assembly line balance problem with the modified ranked positional weight technique. First, according to the processing time and priority relationship of each task, the synthetical ranked positional weight is obtained by taking the time-ranked weight and position-ranked weight into comprehensive consideration. Then the modified ranked positional weight technique is applied to the assembly line balance problem to obtain the balancing results of simple, single U-shaped and double U-shaped assembly lines. With the simple example 1, the comparison of the balance effects is performed in modified ranked positional weight technique and branch-and-bound method. With the experimental example 2, it is proved that the balance effect of modified ranked positional weight technique is better than that of the time-ranked weight technique. Therefore, the modified ranked positional weight technique is an effective method to solve assembly line balance problem.

Abstract:Based on the construction industry data of 30 provinces in China from 2005 to 2016, the main carbon dioxide (CO2) emission sources were identified and used as input indicators to reconstruct the evaluation indicator system of the construction industry total factor carbon productivity (CI-TFCP). The data envelopment analysis method and convergence test method based on production frontier were used to study the CI-TFCP index and its convergence of the provinces from 2005 to 2016. The conclusions are as follows: CI-TFCP in China and its eastern, central and western regions all increase year by year, with the highest average annual growth rate in the east and the lowest in the west. The intensity of materials and energy, technology, education, and energy structure may affect the CI-TFCP index. The average gap between China and its eastern, central and western provinces and the best production frontier provinces, and the gap between the best production frontier and the worst production frontier provinces have been expanding year by year. Based on the above conclusions, suggestions have been proposed for improving the CI-TFCP in China by reducing the intensity of materials, directing R&D investment, and promoting technology diffusion.