Applied Mechanics and Materials Vols. 66-68

Abstract: Due to nonlinearity, preload-dependent spring force and parameters uncertainty in air spring, it is difficult to control this suspension system. To achieve a desired performance, a fuzzy sliding mode controller (FSMC) has been designed to improve the passenger comfort and manipulability of vehicle, in which the fuzzy adaptive system is used to deal with the nonlinearity and uncertainty of the air suspension. A normal linear suspension model with an optimal state feedback control is designed as the reference model. The simulation results show that this control scheme is more effective and robust in the vibration isolation of the vehicle body than is the conventional sliding mode controller (CSMC).

Abstract: To get a deeper understanding of the relationship between the flat belt axial motion (FBAM) and the angles of rollers, a test rig was designed and some experiments were done. The belt axial position was measured though imaging processing. A special filtering procedure was proposed to eliminate the random and systematic errors. Base on the authors’ previous study, the normalized analytical FBAM model was given. By comparing the simulation and experimental results, the effectiveness of the analytical FBAM model was validated. The results also show the relationship between the FBAM and the belt transferring distance is independent of the belt transferring speed.

Abstract: To improve the calculation accuracy of the wrap angles, which are key parameters for the estimation of the maximum torque of the belt system, the steady configuration of the belt was researched. The governing equations and boundary conditions of the belt steady configuration were proposed and the following factors were considered in the model: the centrifugal force, the bending stiffness and the gravity of the belt. The belt steady configuration can be solved through a proposed iteration method based on the built model. The results show the gravity of the belt plays an important role on the belt steady configuration. The wrap angles calculated from the steady configuration are much less than that from the traditional geometric analysis. Thus the maximum torque of the belt system could be overestimated in the traditional belt design theory. It is necessary to calculate the wrap angles by solving the belt steady configuration, especially for the long center distance, high speed belt system.

Abstract: A new theoretical model for the directed thermal diffusion fractalgrowth of thin plate with environmental disturbance is considered to control thediffusion direction. Using the norm theory, a quantitative relationship of such anoptimal control problem is obtained, and the following simulations show that therelationship controls the diffusion direction effectively. In addition, the comparisonof the dimensions between the diffusion with round controlled region and thegrowth with piecewise region illustrates that the controlled regions play differentroles in the real complex fractal growth.

Abstract: The finite element method was used to establish model of radial tire and analysis the characteristics of tire in driving state to improve the accuracy of simulation on driving performance of off-road vehicle. The dynamics models of the vehicle and its subsystem are designed to provide an off-line dynamic simulation for vehicle driving performance. Simulation and analysis for the vehicle selected previously are made, and the simulation results are compared and analyzed in detail to prove the effectiveness of the new method.

Abstract: The effect of alkaline hydrothermal temperature on the transformation of induction heating deposited monetite coatings to hydroxyapatite coatings on the H₂O₂ treated C/C composite was investigated. These monetite coatings were hydrothermally treated for 4h at 353K, 373K and 393K in a 50ml autoclave with 0.1M alkaline solution. After hydrothermal post-treatment, the structure, morphology and the chemical composition of these HA coatings were characterized with XRD, FTIR, SEM and EDS. A scratch test was conducted to measure the strength of the adhesion of the coatings to the HT-C/C substrate. The results showed that only part of hydroxyapatite phases at 393K could be transformed from the monetite coatings on HT-C/C substrate, while pure hydroxyapatite phases were observed to form in the as-converted coatings with critical loads of 45.9N and 51.1N respectively when the alkaline hydrothermal post-treatment treating temperatures were 353K and 373K. The reasons for these results were suggested.

Abstract: Viscoelasticity is an inherent property of the soft biological tissue and is increasingly used as a diagnostic parameter, e.g. in characterizing Brain disease, liver fibrosis and breast tumors or tissue-mimicking phantoms preparation. MR elastography (MRE) enables the noninvasive determination of the viscoelastic behavior of human internal organs. In this study, multifrequency magnetic resonance elastography was used to investigate and validate the numerical simulation of human brain viscoelasticity generated by ABAQUS. The dynamic behavior of storage modulus (G') and loss modulus (G") obtained by MRE at different frequency ranges were used to generate viscoelastic FE model of brain tissue. Then, shear modulus (µ) and shear viscosity (η) were compared to experimental data. MRE validate the finite element as an effective technique for measurement of rheological material properties. Results indicate the capability of FEM to simulation and comparison of experimental results.

Abstract: A two-dimensional electromagnetic eddy current field analysis model of the experimental electro-impulse deicing system (EIDI) is developed. Additionally, a numerical post-processing method is proposed to calculate the deicing excitation exerting on the testing skin. Moreover, a three-dimensional dynamic analysis finite element model of the testing skin loaded the excitation is built for evaluating the response accelerations. Then, the calculated accelerations are compared with the experimental measured data to validate the correctness of the proposed methods. It is obtained that the results agree well, which indicates that it is feasible to use the method of post-processing pressure distribution for solving the deicing excitation and the method of structural dynamic finite element analyzing the testing skin for simulating dynamic response. The presented methods pave a way for ice failure analysis of the EIDI system.

Abstract: This paper studied a phase change process of phase change material (PCM) application building energy storage by CFD software. Set up the phase change process physics model consideration natural convection, the phenomenon of heat transfer from phase change and the impact of rules have been discussed, the proportion of solid and liquid of the process of phase change, the time of phase change, the interface of phase change and motion temperature image of liquid-region carried out numerical simulation. The results show that the natural convection generates the circumfluence at the liquid state of the phase change process, it takes on the role of accelerating the melt and reducing the solidification.

Abstract: Based on the Rate-Variable Fundamental In-tree Modeling Method of the System Dynamics, this paper discusses a problem that how to apply the system dynamics assessment Method based on Level and Rate Variable System in a determined Assessment Index System. It gives a method to determine the Level Variable and Rate Variable System method in the Assessment Index System, and then utilizes Rate-Variable Fundamental In-tree Models depicting the Assessment Index System. Based on this, it applies the System Simulation Assessment on the Supply Chain Performance of the Aviation Weapon Equipment Manufacturing, analyses the feedback dynamic complexity affecting the performance improvement; put forward the relevant Management Countermeasures, which achieves the purpose of analyzing Supply Chain Performance effectively utilizing the System Science Method.