Applied Mechanics and Materials Vol. 835

Abstract: In this paper, the construction treatment technology for the transition section connecting road and culvert founded on the high salt saturated fine sand is carried out, in which an actual project of a new local railway from XieTieshan to North Hobson in China is the background. Meanwhile,the field monitoring and finite element analysis of the settlement law of the transition section are carried out under different load conditions. The results are of referential significance to the settlement law and design of roadbed-culvert transitional section in high salinity regions.

Abstract: In this paper, a key treatment technology of the culvert foundation is presented, which is on the high salt saturated fine sand in a new China local railway from XieTieshan to North Hobsonis. In the procedure，for the two kinds of culvert foundation treatment technology(gravel pile foundation and rubble replacement), the settlement laws of culvert under China-load are explored by comparing with the field observation data and numerical analysis conclusion. The results show that in saline soil area, using rubble fill to reinforce groundwork is a appropriate treatment technology for culvert foundation.

Abstract: A continuum damage mechanics model was proposed to predict the high cycle fatigue life. In order to consider mean stress effects, the Walker correction was introduced in proposed model. The model was verified by experimental data on LC4 and LY12CZ aluminum alloy under high cycle fatigue loading. The results showed that the predicted life of proposed model well correlated with experimental data.

Abstract: The displacements distribution on the depth of an elastic layer under normal loading is offered in this article. To approximate the displacements distribution the exponential dependence is used. The results of analytical approximation are compared to results of calculations by finiteelement method for various thickness of a layer.

Abstract: Acoustic properties of building structures are currently very actual theme with regard to the development of new building and insulating materials, while the methods for estimating the airborne sound reduction index evolve mainly from the second half of the 20^th century. For mutual comparison of selected prediction methods and for determination of their suitability it has been provided a calculation of weighted sound reduction index R_W [dB] from the input parameters of materials identified by laboratory measurements, calculation of weighted apparent sound reduction index R ́_W [dB] and these values were compared with in-situ measurements. The aim of this paper is to determine the most appropriate method to calculate R_W [dB] and R ́_W [dB] values of lightweight building constructions with regard to their practical applicability, accuracy of estimation and complexity of the calculations.

Abstract: The article discusses the problem related to the calculation of a thick-walled concrete hemispherical shell reinforced in the circumferential direction as well as in the meridian direction. The reduced stiffness in the meridian direction is variable. Thus the shell is considered anisotropic and inhomogeneous. The problem was solved in the variational-difference formulation.

Abstract: The present study investigates the non-linear behavior of spherical shells under the influence of static circular ring loads. It is assumed that the material is isotropic and linearly elastic. The differential equations comprising the equilibrium equations, constitutive laws and kinematic equations are converted into non-linear algebraic equations by employing the method of finite differences. Respective non-linear algebraic equations are solved numerically by using the Newton–Raphson Method. The curves pertaining to the circular ring load versus the deflection at the application point of the ring load and the circular ring load versus the deflection at the apical point of the shell are plotted and compared for various shell radius/thickness ratios and parallel circle radii values.

Abstract: This paper presents the theoretical characteristics of elastohydrodynamic lubrication (EHL) in point contact under steady operating conditions of ball bearing thrust bearing. The numerical simulations employed a finite different method, Newton Raphson method and multigrid method to solve the modified Reynolds equation with a Non-Newtonian fluid. The general numerical schemes are implemented to investigate the profile of pressure and film thickness, with varying applied loads viscosity of lubricants and speeds. The results show that the applied load has significant effect on the film thickness profile. The contact is increase area but film thickness decrease as the applied load increase. The minimum film thickness and friction coefficient both increase significantly as viscosity of lubricant is increased. The increasing of surface velocity, the film thickness increase but film pressure decrease.

Abstract: The present paper proves the feasibility of a semi-automatic control system of high frequency ultrasound for welded plastic pipes, by ultrasonic methods. The paper presents the main existing types of plastic materials, the technological joining possibilities, the problems that may occur in welding and control and the reasoning of the chosen examination method. The theoretical size of the reference ultrasonic parameters for the propagation of ultrasounds through the flawless juncture. The samples were welded using electro fusion (EF) under different working conditions. The samples were assessed circumferentially, every 10 degrees, on different working frequencies. A semi-automatic control system was designed and developed. For the optimal working frequency, a set of 10 measurements was done, in similar working conditions, on the automatic control stand, in order to test the systems’ capability and the results’ repeatability. The measured values were compared with the limits considered to be admissible using Shewhart statistic control charts.

Abstract: In this paper, finite element method was used to carry out parameter optimization and structural improvements of CNC machine. Considering the static and dynamic characteristics of the machine, the headstock and bed of CNC machine has been improved by structural optimizationk, and wall ribs was designed on the headstock CNC machine tools. After optimized the static stiffness and strength of CNC machine can meet the requirements, with a decrease of approximately 24.8% in weight compared to the original machine design.