Applied Mechanics and Materials Vols. 300-301

Abstract: Since it is difficult to predict the mechanical property parameters of tube, the parameter prediction method is proposed, which is based on RBF neural network and tube tensile tests. The stress-strain curves of partial tube are investigated by tensile tests. Then, the sample space of a neural network is established. On this basis, the neural network input parameters and output parameters are determined, and the tube is classified according to the sizes and materials to build a layered neural network model. The comparison of Network prediction and experimental results shows that the RBF neural network can effectively predict the mechanical performance parameters of tube.

Abstract: For the deformation problem of an electrostatically actuated cantilever micro-beam, size effect on pull-in behaviors of the micro-beams have been studied based on modified couple stress theory. The approximate analytical solutions to the pull-in voltage and pull-in displacement of the micro-beam are derived by using the Rayleigh-Ritz method. The results show that the normalized pull-in voltage of the cantilever micro-beam is size-dependent and the normalized pull-in displacement of the micro-beam is size independence.

Abstract: In this paper, flow patterns transition criteria from bubble growth to confined bubbly flow, from isolated/confined bubbly flow to slug flow, and from slug flow to annular flow are numerical analyzed. The prediction of the theoretical model agrees well with experimental data. By carrying out comparative study, it is indicated that there is an apparent postponement of flow patterns transition of flow boiling in mini/micro-channel than that under adiabatic conditions.

Abstract: According to the Near-Field Acoustic Holography (NAH) theory, we designed a measurement system, which was used to localize the noise source on five hologram surfaces of a industrial sewing machine. Moreover, we compared the localization results of the noise source on the front surface of the industrial sewing machine by NAH and sound intensity method respectively. The measurement results can provide a theoretical basis for controlling the noise of industrial sewing machine.

Abstract: In order to design a large aperture primary mirror with the diameter of 1150 mm, the parameters impacting on gravity deformation of the mirror were analyzed and discussed in detail, including material selection, diameter-thickness ratio, the number of the support points, location selection and lightweight structure, etc. A novel space mirror structure system was put forward, and its back was opened and supported by six points on back. The dynamic and static and thermal characteristics were analyzed based on the finite element method. Analysis results showed the surface figure accuracy reached to RMS 14.5nm under the action of gravity load along the optical axis direction and the first-order natural frequency was 214Hz which met to the designed indexes requirements.

Abstract: The box-type field kitchen units is used to guarantee the diet in field operations for troops, a set of box-type field kitchen units includes 3 boxes and 1 tent (a kind of rotationally-molding material is applicable to box-type military kitchen equipments), cooking staple and non-staple food for 150 people in one hour. Meanwhile, it can supply 75 or 300 people by modularization. The unit weight of box-type field kitchen units is not exceeding 112KG, which can be loaded on the vehicle by 2-people moving laterally or 3-people lifting. Stacking is done frequently in transit, and always suffered from bump and impact; therefore, the structural strength is the key point of design. ANSYS is applied in this paper to make analysis on finite element structural strength, assist to make design, simulate the load-carrying condition of box under the condition of stacking and horizontal impact, guiding the design and production in the end.

Abstract: This paper presents the power generation performances of an array of three microelectromechanical system (MEMS) acoustic energy harvesters equiped with lead–zirconate–titanate (PZT) capacitors. The PZT acoustic energy harvesters had a diaphragm with a　diameter of 2 mm consisting of Al (0.1 μm) / PZT (1 μm) / Pt (0.1 μm) / Ti (0.1 μm) / SiO₂ (1.5 μm), and the diaphragm vibrations were excited by sound pressure. The arrayed peripheral energy harvester generated a maximum power of 2.26 × 10^-10 W at a sound pressure level (SPL) of 100 dB at 5 kHz. The output power of three arraying devices was about 3 times larger than that of the single devices.

Abstract: A real-time monitoring method for brake temperature rise in continuous long downhill with constant velocity braking is proposed. Longitudinal equilibrium equation and energy balance equation are built, and the proportion of brake dissipation energy in total is analyzed. The influence of velocity on brake dissipation energy is studied, then, the calculation model for brake temperature rise is built with the empirical formula of the proportion of bake absorption energy in dissipation energy. Finally, the undetermined coefficient of the calculation model for brake temperature rise is determined with least square method based on test data. The studies show that temperature rise calculated by the built model is similar to the test data both in magnitude and variation trend.

Abstract: This paper present multi-physical transient analysis of eddy current damper (ECD) for reaction force compensation device. A reaction force compensation mechanism with a movable magnet track and an ECD (or conductor plate) is developed. Lumped model of the ECD is derived and effects of both the location and width of the conductor plate are discussed. Multi-physical transient analysis of ECD is analyzed using commercial finite element software, which is compared with the lumped parameter analysis.

Abstract: The particle concentration and convection velocity profile has been obtained by the adaptation of the random surface renewal model to the particle continuity and momentum equations of the nonisothermal turbulence boundary-layer flows In general, the investigations of particle deposition mainly include incompressible fluid laden by spherical and dilute particles in the fully developed turbulence boundary layer flows. This means that the fluid motion is unaffected by the presence of the particles and that the collisions between particles can be neglected. the relative quiescent viscous sublayer, resulting in the increase in thermophoretic deposition with increased Prandtl number.