Applied Mechanics and Materials Vol. 147

Abstract: Retracted article: Contrast experiments on the effect of concentration of the total phosphorus(TP) on treatment efficiency of artificial wetland are carried out through changing TP concentration of influent water into surface flow(SF) and subsurface flow(SSF) wetlands and growing six plants (purple-leaf canna, water onion, water hyacinth, oenanthe javanica, calamus, reed). Treatment efficiencies of SF and SSF wetlands with the six plants varying with TP concentration change are analyzed, and some indexes of purifying function of SF and SSF wetlands with six plants including theoretically optimum treatment concentrations and removal efficiencies, actual optimum treatment concentrations and removal efficiencies, and TP maximum daily treatment loads, are obtained. The experimental results show that, TP removal efficiencies of SF and SSF wetlands with the six plants decrease with the increases of TP concentrations, different plants have different levels of treatment efficiency reduction, and the reduction of removal efficiency of SSF wetland is smaller than that of SF wetland. Removal efficiency of water hyacinth is little changed with the increase of TP concentration, and treatment efficiencies of SF and SSF wetlands decrease by 1.61% and 1.12% respectively. Removal efficiency of Canna is obvious changed, and treatment efficiencies of SF and SSF wetlands decrease by 2.94% and 2.55% respectively. Purple leaf cama had the least changes in the decrease of removal rate, and the table stream processing rate decreased by 17.07%, and subsurface flow by 15.94%. The decrease in the removal rate of reed was clear and its table stream processing rate decreased by 20.86% and wubsurface flow by 18.2%. The actual optimum removal efficiency of SF wetland with water hyacinth is the largest of these SF wetlands’ and reaches 85.2%, and its corresponding maximum daily treatment load of TP is 81g /( d • m2). But the actual optimal removal efficiency of SF wetland with oenanthe javanica is the smallest of these SF wetlands’ and is 76.88%, and its corresponding maximum daily treatment load of TP is 51.84g/( d • m2). The actual optimum removal efficiency of SSF wetland with water hyacinth is also the largest of these SSF wetlands’ and is just 88.31%, and its corresponding maximum daily treatment load of TP is 102.6g/( d • m2). The actual optimum removal efficiency of SSF wetland with cama is the smallest of these SSF wetlands’ and is only 78.32%, and its corresponding maximum daily treatment load is 55.2g/( d • m2).

Abstract: In order to solve the difficult in calculating cable vibration, the non-linear dynamic model of cable was set up with geometrical non-linearity. The differential equation was solved using the singular perturbation method. The analytical expression of frequency and form function was deduced. The expression can be widely used for the field of measurement of cable force and identification of parameter in cable structure.

Abstract: According to vibration characteristic of cable in cable-stayed bridges, the non-linear dynamic model of cables was set up. The vibration differential equation is deduced using the singular perturbation method. The stiffness and coupling boundary conditions of simple and fixed are introduced in the cable force analysis. The useful formulation of measuring techniques for cable force using frequency method is advanced. Results of analyses indicate that the formulation is high in accuracy and convenient in practice. The formulation was used to the cable-stayed construction control of Nanjing Yangtze River No.3 Bridge. The cable force was calculated with test data of vibration, and compared to cable force of design and pressure sensor. The method can be widely used for field of measurement during the construction of cable system structures.

Abstract: Transmission tower, being of evident nonlinear characteristic, is a complex space structure. Linear theory is generally adopted in the process of designing, which results in a waste of resource and disaster. Starting from the problems exiting in the process of transmission tower designing, the space beam element is adopted in the thesis, which reduces material nonlinearity through the rod end of the plastic method, and the geometric large deformation problem is involved by considering the amendment of the element stiffness matrix. Arc-length method of iterative computation is adopted as the solution method. On the premise of clarifying the process of dual non-linear solution, this thesis combines specific project example through self-organizing the finite element programming to calculate displacement - load curve, and the results show that the transmission tower structural system possesses obvious nonlinear characteristics. The research lays a foundation for improving the accuracy of space truss structure and developing the large specific finite element software.

Abstract: An experimental study was carried out to examine the material and structural properties of a new type of structural insulated panel (SIP) comprising the plywood board as facial panels and the Styrofoam as the core material. Material properties were characterized by subjecting specimens to bending, compression, tension and double shear tests. SIP specimens, both in small-scale and prototype sizes, were tested under bending, racking and axial loads respectively. This paper will report these tests and the obtained results.

Abstract: Recently, the light materials have been applied in order to reduce the cost of construction. Since its soundproofing is generally poor, it presented a new problem of noise pollution for office building during our noise control projects. Based on “Acoustics - Specifications for the Design of Sound Insulation in Civilian Structure” （GBJ118-88）and taken an office and meeting room for examples in a building, the good soundproofing material was selected and researched and its performance met the noise requirement of various rooms through compared with performance of soundproofing for various wall material. As a result, the noise of office and meeting room reduced from 67.2 dB (A) and 57.3dB(A) to below 55dB(A) and 50dB(A) separately.

Abstract: Based on the two-dimensional elasticity,the symplectic method is applied to study analytically the stress distributions of anisotropic beam.Using variation principle and introducing separation of variables, dual equations were presented.Then in the symplectic space which consists of the original variables and their dual variables,the problem can be solved via effective mathematical physics methods such as the method of sepatation of variables and eigenfunction vector expansion.So the original problems come down to solve the eigensolutions of zero eigenvalue and non-zeroes eigenvalue that describe the exponentially decaying localized solutions usually ignored by Saint-Venant's principle. Completed numerical examples are newly given to compare with established results.

Abstract: The alien space meridians stair steel structure is first adopted in Taizhou medical city exhibition center project. Based on the finite element calculation method for curved beam element stiffness matrix, convergence standard controls and iteration method of solving the modification and optimization in this paper, the complex alien space meridians framed calculation model is built, and the distribution of axial force and bending moment distribution of the stairs meridians skeleton structure are calculated, and the position and numbers are determined. Numerical results show that the maximum space alien meridians stair axial force is 34.5 KN and maximum bending moment is 5.9 KN•m, which satisfy the standard requirement, then the size curvature big, mechanical transmission line complex and local internal force big technology problem skeleton structure have been solved .Therefore, a strong engineering application value achieves in this paper.

Abstract: In this study, structural defects of existing 709 reinforced concrete (RC) buildings in Eskisehir Province were represented. Structural defects such as gaps between adjacent buildings, strong beam-weak column, mezzanine floor, short column, corner column, discontinuous frame, anchorage beams, long span, segregation, corrosion, inconvenient column/beam lateral reinforcement, low concrete strength and inconvenient steel reinforcement were determined in the study. It was determined that %35 of existing buildings have discontinuous frame, %16 of them have long span problem. It was also observed that nearly %40 of the buildings have no column/beam lateral reinforcement and %70 of them have inadequate gaps.

Abstract: Hangers are very important components for suspension bridges, which link main cables and stiffening girders. When in service, hangers are much vulnerable to fatigue loads due to kinds of traffic flows, which may reduce the remaining life of the hangers and increase the risk of losing public confidence in cable supported bridges. In order to quantify the reliability of hangers under vehicle loads, fatigue reliability formula of hangers is proposed in this paper. Based on the accurate analysis of vehicle load spectrum, the time history of hangers is simulated and maintenance strategy is proposed.