Applied Mechanics and Materials Vols. 249-250

Abstract: Adhesion coefficient between tire and road is one of important factors which influence vehicle safety performance. On the basis of theoretical analysis, the detection method of adhesion coefficient based on brake-by-wire is put forward. Brake force is estimated according to pedal position sensor, vehicle braking deceleration is detected through MMA6260Q acceleration sensor. Motion state of tire is distinguished according to brake force and road braking force, vertical load of tire is received in view of formula on vehicle load transfer. Adhesion coefficient used for sliding area is got and taken as adhesion coefficient of road. Analysis shows that the detection method may identify adhesion coefficient between tire and road accurately, and has certain practical value.

Abstract: In elasto-plasticity computation on materials by sub-increase finite element method, in general, it is necessary to calculate the consistent tangent modulus of elements. In this paper, based on the backward Euler integration, for an unified viscoplasticity constitutive equations, a new expression of consistent tangent modulus is derived for rate-dependent plasticity. The constitutive equations and consistent tangent modulus expression are implemented into a commercial finite element code-MARC. Numerical examples are given to verify the finite element implementation.This template explains and demonstrates how to prepare your camera-ready paper for Trans Tech Publications. The best is to read these instructions and follow the outline of this text.

Abstract: An analytical model of the flow sensor of thermal type is developed. The results of the model application are used to develop a flow microsensor of thermal type with optimal functional characteristics. The technology of microsensor manufacturing is provided. The prototype of the microsensor suitable for use in the mass air flow meter is created. The basic characteristics of the microsensor are presented.

Abstract: The power trend of using server systems in data center is continuously increasing. Cooling system consumed 38% of total energy usage which is a significant contribution in the energy consumption. As a result, the efficient energy usage in data center is concerned.Normally a raised-floor is widely used in data center cooling system which delivers cool air through perforated tiles to a front of server racks. However it is usually found that this cool air cannot effectively remove a heat dissipation at the top of server racks. Therefore, the environmental condition in data center must be designed strictly to avoid disruption that caused by overheat.This paper gives some guidelines to help in the better design. Commercial Computational Fluid Dynamics (CFD) program was used to analyze the air flow from raised-floor air conditioning system. A tetrahedral of 1.8 million meshes with k- turbulence model were used to obtain the air flow velocity and temperature distributions in the room. The model was validated by comparing simulation results with actual measurements. As a result, dimensionless parameters in the form of supply heat index(SHI), for understanding the optimization of relative airflow distribution to the heat load of server rack was found. It shows that these parameters provide an effective tool to the improvement of energy efficiency in raised floor data center.

Abstract: One-dimensional process of formation and the subsequent motion of a plane transverse shock wave is studied on the basis of solutions of the corresponding nonlinear evolutionary equation. This equation defines behaviour of the solution in front area of wave process and follows from inner series of a matched asymptotic expansions method. A comparative analysis of the volume deformation and forming processes will be carried out and their basic differences are specified. In the capacity of model examples solutions of some concrete boundary value problems of a dynamic shear deformation are observed.

Abstract: This paper proposes a structural damage detection method based on wavelet packet decomposition, non-negative matrix factorization (NMF) and a relevance vector machine (RVM). First, vibration data at multiple points are used to calculate the wavelet packet node energies and construct a non-negative damage feature matrix. Second, to increase the damage detection accuracy, the NMF technique is employed to obtain the reduced dimensional representation of the non-negative damage feature matrix and extract the underlying features. Last, the RVM, a powerful tool for classification and regression, that can obtain the probability estimation for classification, is used to determine the relationship between features extracted with NMF and the corresponding damage patterns by considering the measurement noise. The trained RVMs are then used to perform damage pattern identification and classification of an unknown state structure. Numerical study on the Binzhou Yellow River Highway Bridge is carried out to validate the ability of the proposed method in damage detection. The results show that the RVM can achieve a high accuracy in damage pattern identification accuracy using the features extracted by NMF.

Abstract: In this paper, the sufficient condition for the existence of periodic solution of a class of three dimensional nonlinear dynamical systems is investigated. The moving Frenet frame is established on the closed orbit and the successor functions near the closed orbit are defined. According to the study of the existence of solution of the equation which obtained from the successor functions with the implicit function theorem, the sufficient condition for the existence of periodic solution of these systems is obtained. The results in this paper have important significance to decide the existence of periodic solution of three dimensional nonlinear dynamical systems.

Abstract: A combination method of kernel principal component analysis (KPCA) and independent component analysis (ICA) for process monitoring is proposed. The new method is a two-phase algorithm: whitened KPCA plus ICA. KPCA spheres data and makes the data structure become as linearly separable as possible by virtue of an implicit nonlinear mapping determined by kernel. ICA seeks the projection directions in the KPCA whitened space, making the distribution of the projected data as non-gaussian as possible. The application to the Tennessee Eastman (TE) simulated process indicates that the proposed process monitoring method can effectively capture the nonlinear relationship in process variables. Its performance significantly outperforms monitoring method based on ICA or KPCA.

Abstract: Downbursts, which resulted from the flow downdraft in thunderstorms, have become one of the most destructive disasters to buildings including transmission towers, etc. This disaster has drawn researchers’ interests and progresses have been continuously made by employing test and numerical tools. Accounting for the grid validations in the numerical simulation of downbursts, eight grids with different grid point distributions are generated, and then their corresponding flow fields are calculated by solving Navier-Stokes equations. The numerical results are compared with test results to investigate the influence of grid distributions onto numerical results. The results indicate that, numerical fidelity could be improved by refining grids in the zone with strong horizontal wind; while local grid refinement at inlet boundary could deteriorate numerical accuracy when the grid point number is kept constant, hence uniform grid distribution is recommended at inlet boundary without any grid refinement.

Abstract: Jia and coworkers [1] have shown that with =M_N and  ̃=M_1as a pair of locally supported refinable functions, one can construct a function, _N(N being an odd integer) given by _N≔∑_(j=0)^N▒〖((-1)^j)/2 [M_(N+1) (j)+M_N (j+1) ] M_N (2∙-j)〗. Here M_N is a binary spline function of degree N. For r =0, 1, 2, …, N-1, the set {2^(j/2) _N^((r) ) (2^j∙-j);j,k ϵ Z} is a Riesz basis for L_2 (R). This base involves the first N-1 derivatives of the generating function and therefore is useful for dynamical systems with derivative constraints.