Applied Mechanics and Materials Vols. 152-154

Abstract: The integrity of coatings used on the surface of blades of gas turbines determines the reliability of the blades. Coatings life usually dictates blades refurbishment intervals. The failure investigation and life assessment of coatings are essential for the effective management of blades. In this paper, coatings failure mechanisms are investigated by examination of service-exposed blades, and a methodology of coatings life assessment is described.

Abstract: Vehicles drag reductions arising from close spacing are studied and verified by some research institutes. But this solution was queried by an experiment carried in RMIT University in 2006. Based on two standard Ahmed Bodies, Computational Fluid Dynamics(CFD) method is used to study this problem in this paper. The calculation results by comparing four different CFD turbulence models show that the drag coefficient of the rear car is more than the lead car, and even more than the isolated car when the space of these two cars is less than one time of car length. Furthermore, the calculate results of these four turbulence models show that the standard model is the best model to simulate this problem, and different far field condition will influence the calculate results much more. Therefore, the research of this paper verifies that drag reductions from close spacing still need to be studied.

Abstract: The soil pressure can be influenced by the deformation of retaining wall because of the interaction of wall and soil. The dynamic soil pressure and plastic bottom displacement induced by earthquake action will subsequently result the deformation of the wall. The dynamic soil pressure will vary with the wall deformation and, on the other hand, change the deformation of the wall. The wall under lateral earthquake is assumed to be a single freedom system, thus only one deformation mode is considered in this paper. Based on this assumption, the differential equation of wall-soil dynamic interaction system is proposed.

Abstract: Compared with the coaxial coil gun, the structure of parallel coil gun is conducive to release the effective load which carried by the emitter, and easy to add the suspension device. So, for some massive emitter which could not be easy wrapped inside of the barrel, to design an open parallel coil gun with a high temperature superconducting (HTS) maglev assist device is great significance. The directions of driving force are inconsistent during the drive current pulse up and down under only one coil driven. Eliminating the resistance is an effective way to improve the emission efficiency. A new mode of single-stage and multi-stage driven is designed in this paper. The pulse link up method between the various coils is analyzed. And then a small parallel coil gun model is established in the finite element software ANSOFT. The propulsion effects of single-stage and two-stage driven are simulated. And the feasibility of this driven mode is verified by these simulation results.

Abstract: Overall scheme for large-aircraft Intelligence Virtual Maintenance Training System (IVMTS) information model which integrates the Standard for the Exchange of Product model data (STEP) standard geometric model with agent model is presented in this paper. Firstly, the system multi-agent model architecture are constructed. Secondly, Integrated STEP standard geometric model with agent model and maintenance applying information, the maintenance object agent IP(intelligence part) ,IB(intelligence body) and IT(intelligence tool) are constructed utilizing the EPRESS-G language. Thirdly, the communication method between components and system level agents is presented based on Blackboard model each other. Finally, how to realize the model under catia-caa secondary development method is described, and the intelligence maintenance process simulation, maintenance of the elements of the intelligent interaction, intelligence collision detection and maintenance sequence optimization simulation can be realized in this method in IVMTS.

Abstract: ICPF (Ionic Conducting Polymer Film) is a kind of smart film and has the characteristics of flexibility, good response and being driven by a low voltage. In order to illuminate the deformation dynamics of ICPF, the curvature of a thin strip ICPF under stepwise application of electric field is formulated according to Flory’s gel swell theory. The interplay mechanism of the deformation of gel, permeation of water and the transport of ions is described. A novel fish-like flexible micro-robot whose fin is actuated by ICPF is presented. According to the Pseudo-Rigid-Body-Dynamic-Model (PRBDM) the frequency analysis of the micro-robot is investigated, and then, the relation between the structure parameters and the natural frequency of the fin is theoretically derived and some analysis and experiment graphs about the fin’s angle displacement and angle velocity are performed.

Abstract: As energy shortages in recent years, pollution-free cars are urgent needed, so electric cars become engineering research focus. Dynamics of vehicle with four independently-driving wheels is analyzed to show the purpose of vehicle running control. Dynamic response model of driving system is obtained through system identification, and then be transformed into a control model of driving system. The whole vehicle control method is designed, guaranteed cost control theory is used to design system feedback controller. The equality torque driving force distribution strategy is applied in experiment, and this method has achieved good results.

Abstract: Semi-analytical finite strip method (FSM) for analyzing the buckling behavior of some functionally graded plates is presented in this paper. The plates are assumed to be under three types of mechanical loadings, namely; uniaxial compression, biaxial compression, and biaxial compression and tension. The material properties are assumed to vary in the thickness direction according to the power-law variation in terms of volume fractions of the constituents. Thus, the material properties are estimated from the both Voigt rule of mixtures (VRM) and Mori-Tanaka homogenization method (MTM). Numerical results for a variety of functionally graded plates with different aspect ratio are given and compared.

Abstract: The dynamic instability of cylindrical shell panels having longitudinal stiffener is studied by using the developed finite strip method (FSM). The method is formulated using the third order shear deformation shell's theory of Reddy's form and the Koiter-Sanders theory for cylindrical shells is implemented. The lay-up effects of skin as well as the stiffener are investigated.

Abstract: The finite element model of damping plate for the airbag Vibration Damper was established.Displacement and stress analysis of the damping plate structure was done by means of software ANSYS,and the displacement diagram and effective stress distribution of the of damping plate were obtained. The simulation results indicate that the bottom zones of damping plate , which bear considerably great forces,and the displacement variation of the hole have less influence, it could satisfy the demand of sustained vibration attenuation.