Abstract:This paper presents an analytical method to calculate the dynamic response of tunnel embedded in saturated foundation with an unsaturated super-stratum. The vibration characteristics of foundation soil and tunnel lining were simulated by unsaturated wave equation and shell vibration equation respectively. Based on the method of separating variables and Helmholtz vector decomposition theorem， the expression of total wave field can be obtained， which includes cylindrical wave and plane wave. The system dynamic response was solved by the wave function transformation method， based on the boundary assumptions of foundation surface， soil interface and tunnel soil interface. The proposed method was verified by comparing with the existing models. Finally， based on the proposed method， the dynamic response of system was analyzed by a cases study. The results show that the displacement response of the ground is affected by the overlying unsaturated soil layer. The critical velocity is less affected by the saturation of overlying soil and mainly affected by the characteristics of soil that tunnel located.

Abstract:Based on the finite element model of cracked steel plates， the influences of drilling-hole diameter and the pre-tightening force on the stress distribution and the crack arrest mechanism of the repaired steel plates are investigated to analyze the crack arrest effects of high strength bolt stop-hole method. After the pre-cracked steel plates were repaired， three groups of comparative fatigue tests were carried out to evaluate the fatigue life of the structures under various repair methods， and compared the test data with the relevant S-N curve provided by national codes. Analysis and test results indicate that two repair methods can prolong the fatigue life of the damaged steel plates， but the repairing efficiency of high strength bolt stop-hole repair method is better. Moreover， its fatigue life is over 9 times that of the steel plates by the only stop-hole repair method. According to the stress change criterion， to employ the stop-hole repair alone is not enough to satisfy the fatigue strength category specified by national standards， and the high-strength bolt stop-hole repair group is significantly higher than the category A of AASHTO， which has excellent fatigue resistance.

Abstract:The arch bridge stability declines when the span increases. The phenomena such as shearing and bending deformation tend to happen with moving load. Put the rigid bar between the main girder and arch rib to form a triangulation network， and then the triangulation network， arch rib and main beam compose a continuous series triangles. The stability of the triangle is used to improve the linear stiffness of the main beam and arch rib， so as to improve the overall stiffness of the structure. When the bridge is under moving load， the triangle must be subjected to the non-node load， which reduces the stability of the triangle. Therefore， suspender and columns are set to increase the elastic constraint and reduce bending and shear deformation between nodes. In addition， integral nodes can be used to simplify the structure with the proposed method of precast-assemble for construction which is convenient and fast . The concrete structure of the scheme is given， the mechanics principle is expounded， and the trial designing of half-through arch bridge with the main span of 1 008m is carried out. The finite element results show that the strength， stiffness， stability and dynamic characteristics of the presented arch bridge meet the requirements with a better mechanical properties than traditional arch bridges and proposed design is more economical.

Abstract:The driving data of car driving in low-grade highway was collected from the simulation experiment. Focus on the horizontal risk versus vertical risk， 8 major statistics were calculated from the driving data， from which， 3 core statistics （standard deviation of velocity， tangential acceleration and steering wheel speed） were screened by principal component analysis（PCA）. Based on the 3 core statistics， 4 kinds of risks （weak risk， sharp brake， sharp turn， strong risk） were separated by k-mean clustering. Then， a risk prediction model of vehicle driving in small curves was founded based on Fisher， whose test set was the 3 core statistics of the initial 1/4 period that vehicle driving in curves， and training set was that of the whole curve. The accuracy of the risk prediction model was 76.5%.

Abstract:A design and calculation method was proposed for determining horizontal linear elements through two points. The segmentary elements of the horizontal alignment can be divided into six classifications： tangential straight line， circular curve， and four types of clothoids. There are no more than 4 dependent parameters for each segmentary element. When designing horizontal alignment by the segmentary element method， the three parameters related to the origin point are known. Thus， once the coordinate of the destination point is available， the six basic types of segmentary elements and the remaining parameters can be uniquely determined simply by using the origin and destination points of the segmentary element， which is similar to the determination of a straight line through two points. The calculation of the deflection angle of the segmentary element is the key to solving the parameters. For the circular curves the analytical method is employed， whereas for the clothoids the iterative method is recommended. The deflection angle can be estimated by fitting formula of polynomial， with the error which is less than 1.0%. The two-point segmentary element method emphasizes the control effect of the coordinates’ location on the alignment， in which the alignment is easy to control through the destination location of the segmentary elements. The method is applicable to the complex horizontal alignment design for roads at the interchange ramp and hilly area as well as the reconstruction of the existing road alignments.

Abstract:A 3D wheel-rail transient rolling contact model accounting for sleeper hanging behavior was developed based on the explicit finite element method. The dynamic wheel-rail interaction affected by both rail surface irregularity and unsupported sleepers is reproduced， and the influence of hanging gap and number of sleepers at rail weld irregularity is analyzed. The results indicate that the presence of unsupported sleepers enlarges wheel-rail impact at rail weld irregularity. Subsequently， the yield deformation of rail materials was exacerbated， and the situation becomes even worse with the growth of unsupported sleeper number. Under the condition of 2 adjacent sleepers being completely unsupported， the parameters in terms of wheel-rail contact force， contact stress， contact patch size and von Mises strain of rail top-layer elements increase by 14.5%， 4.2%， 8.5% and 6.7% compared to nominal condition， the vertical displacement of rail surface nodes rises by 72.0% in the meantime， whereas the distribution of adhesion-slip state is much less affected. Meanwhile. under the incompletely unsupported condition， the preceding contact parameters rise rapidly as the hanging gap is higher than 1.0 mm for 1 sleeper or 1.3 mm for 2 adjacent sleepers， until completely unsupported condition occurs.

Abstract:Anisotropy in strength between layers and filaments in fused deposition modeling （FDM） additive manufacturing has a significant influence on mechanical properties of fabricated objects. A method was proposed to improve mechanical properties of the part by the design of the infill toolpath to make it in alignment with the load paths under the guidance of principal stress lines （PSL）. The PSL generation method based on finite element analysis and the PSL visualization method based on Grasshopper were presented. The region toolpath generation algorithm based on PSL seed lines and the toolpath-to-Gcode conversion method were put forward. Tensile and three-point bending mechanical tests were carried out. Compared with the traditional infill toolpaths in the 0°and 90° direction， the tensile strength of the PSL-based printed specimens increased by 8.33% and 19.74%， and the bending strength of the PSL-based printed specimens increased by 11.46% and 20.47%， respectively.

Abstract:Machine degradation may cause product quality degradation in production. Therefore， a joint optimization model of lot-streaming scheduling and preventive maintenance considering the relationship between product quality and machine degradation was established. The machines were assumed to have two states of "controlled" and "out of control". The stochastic dependence between upstream machines and downstream machines was established using the unqualified products produced by "out of control" machines. Based on the above-mentioned descriptions， a mathematical model with an objective function for minimizing the makespan and the total expected cost was derived. The improved differential evolution algorithm was designed to solve the model. Finally， the convergence of the algorithm and the effectiveness of the model were verified by numerical results and the comparative experiments respectively.

Abstract:In order to better understand the energy consumption performance of parallel plug-in hybrid electric vehicle （PHEV） and to analyze the impact factors under the hybrid driving mode， the working modes were identified for more accurate energy consumption analysis with real-world travel data. The methodology for identifying the different working modes is proposed. A multivariable non-linear regression model is used to analyze the effects of different factors on energy consumption rate （ECR）. Based on the analyses of real-world longitudinal travel data of 425 PHEVs in Shanghai， it is found that the energy consumption performance of a PHEV depends to a large extent on the driving environment and driving pattern and the energy cost of the PHEV is more effective compared to conventional fuel vehicles. The ECR of the sample PHEVs saves up to 37.9% compared to the conventional gasoline vehicle BYD Song， and is about 2.96 times of that for the Battery Electric Vehicle （BEV）. The speed and temperature have significant quadratic effects on ECR， and the acceleration rate has a strong linear positive effect.

Abstract:Satellite clock affects the positioning accuracy the most. Based on a study of the pseudorange observation accuracy of different receivers and corresponding phase variance， a reasonable stochastic model was established. The GPS data from 56 IGS stations were connected to estimate the satellite clock and to analyze the positioning performance. The estimation results of the satellite clock based on this method prove to the positioning accuracy improve about 5% in comparison with the traditional clock estimation method. The stochastic model was employed to the positioning solution using the IGS satellite clock. Within 10 stations， the convergence time and positioning accuracy of 7 stations improved significantly. Compared with the traditional fixed weight method， the convergence time improves about 78% the most， and the positioning accuracy improves about 86.55% the most.

Abstract:To meet the real-time， high-precision and non-contact vibration detection requirements of high-speed railway bridge， this paper investigates the theory of vertical vibration model of bridge and the precise ranging algorithm of millimeter wave radar. Based on the IWR1443 millimeter wave radar chip， a millimeter wave radar measurement system is developed to realize the integration of vibration signal measurement， acquisition， decoding and processing. Then the vibration detection experiment of 32m simply supported bridges in Xuzhou section of SUIHE super large bridge on Beijing-Shanghai line is carried out with this measurement system， and the data are analyzed by time-frequency analysis method. Analysis results show that the three-dimensional spectrum array， which is extracted by the generalized S-transform and the standard time-frequency transform， reveals the bridge vibration process under the dynamic load of the high-speed train. The dynamic vertical deflection， the deflection span ratio， the main frequencies and vibration type of bridge are determined， which are consistent with the theoretical analysis， and the performance of bridge structure is better than current design limit value of high speed railway. This indicates the SUIHE bridge structure is in good health and verifies the accuracy and effectiveness of millimeter wave radar measurement system.

Abstract:A fast collocation scheme can be used to discretize the variable-coef?cient nonlocal diffusion model effectively. The coefficient matrix of the resulting linear system is unsymmetrical， dense and Toeplitz-like. The generalized minimum residual （GMRES） method can be employed to solve the discretized linear systems. In order to improve the rate of convergence of the GMRES method， the Toeplitz preconditioner and circulant preconditioner are constructed for the coefficient matrix， and the preconditioned GMRES methods are proposed for solving the discretized linear systems. Numerical examples are presented to illustrate the effectiveness of the preconditioned methods.

Abstract:Based on the sound insulation theoretical model and experimental data of the double-layer plate structure， the sound transmission loss of the sealing strip was investigated in different air pressure. The results indicate that the air density decreases with the decrease of the air pressure in the source room， which leads to the increase of the sound transmission loss of the sealing strip. At the same time， the decrease of air pressure causes the membrane stresses of the sealing strip and then improves the material stiffness， which leads to the further increase of the sound transmission loss in the stiffness area. Because the sound insulation performance of the sealing strip is affected by both the air density and the pressure difference， it is necessary to pay attention to the change in the sound insulation performance when using the sealing strip in special situations such as high altitude.

Abstract:This paper proposes a multi criteria decision making （MCDM） framework for evaluating the quality of data assets by combining the best worst method （BWM）， technique for order preference by similarity to an ideal solution （TOPSIS） and triangular fuzzy number. In this framework， firstly， the evaluation indexes are constructed through expert interviews. Then， the BWM method is used to determine the weight of the evaluation indexes. After that， experts are invited to linguistically evaluate the quality of the data set based on the constructed indexes， and triangular fuzzy numbers are introduced to overcome the problem of incomplete expression of individual real numbers. Finally， the TOPSIS method is utilized to rank the quality of the data assets. The feasibility of the methodology is verified by applying the proposed approach to data asset quality assessment of commercial banks.

Abstract:To solve the "black box" issue in the efficiency evaluation of the logistics industry， the production process of the logistics industry was divided into investment transformation stage and society service stage. An efficiency evaluation model of a two-stage network structure for the logistics industry was proposed with the consideration of undesired output. To prove the rationality and effectiveness， the proposed model was applied to China’s regional logistics industries. Some policy suggestions were provided for improving efficiency for the logistics industry.

Abstract:An improved FMEA method based on cloud model and agglomerated hierarchical clustering algorithm is proposed as to improve the RPN algorithm of failure mode and effect analysis （FMEA）. Firstly， the expert evaluation information is described and aggregated by the cloud model. Then， the cloud model is improved by the agglomerated hierarchical clustering algorithm， the correlation relationship among the failure modes is determined according to the clustering sub-clusters of the cloud model， and the risk level of the failure modes is determined according to the clustering results. Finally， the application and validity of the improved FMEA method are verified， by taking the online teaching failure risk assessment as an example.

Abstract:This paper selects the medical and health listed companies on the Shanghai and Shenzhen Stock Exchanges from 2013 to 2019 as the research samples， and uses logistic regression and multiple linear regression analysis methods were employed to study the impact of government innovation R&D subsidies on the innovation R&D of medical and health companies under different regulatory constraints， as well as the differences of this kind of influence in different regions and under different enterprise nature situations The research conclusions provide a decision-making basis for the government to rationally formulate innovation subsidy policies and medical and health enterprises to improve their innovation capabilities.