Applied Mechanics and Materials Vols. 121-126

Abstract: The search and rescue robot has the characteristics of quadruped walking machine. According to the actual structure of the quadruped robot body，the walking pose of the robot are planned，based on the study of the animal gait．The distributions of degrees-of-freedom is analyzed to ensure stable walking. A simulation model of quadruped search and rescue robot is established in ADAMS, and the motion characteristics of the system are observed using the simulation model established. Simulation results show that the motion characteristics of the system are closed related to the length of stride.

Abstract: Exhaust valve is the key component of the reciprocating high temperature booster pump, its performance will directly affect the characteristic of the reciprocating high temperature booster pump. In order to improve the performance of the booster pump from structural optimization design, two types of exhaust valve are designed. Finite volume method is used to simulate the velocity filed and pressure field of the two types of exhaust valve. Simulation results show that the velocity gradient and pressure gradient of the cone-type exhaust valve is smaller and more uniform than the disk-type exhaust valve, and the performance of cone-type exhaust valve is better than the performance of disk-type exhaust valve, which provides the valuable theoretical basis for the exhaust valve in the practical production.

Abstract: A ultrasonic vibration system with ram motion of two steps is developed to optimize the formability for thin workpiece at the end of forming. The deep drawing force and forming height can be predicted in view of optimizing the values of the working variables involved in the process parameters. A response surface methodology (RSM) based on design of experiments was used in order to minimize the forming force and maximum the forming height during the deep drawing process. Associated plots are shown to be efficient for a quick choice of the optimum values of the forming process parameters.

Abstract: Rare earth europium (Eu(III))-pyromellitic acid (H4L)-1,10-phenanthroline (phen) ternary luminescent complex has been synthesized in polyvinylpyrrolidone (PVP) matrix by precipitation method. The chemical constitution of the complex has been demonstrated as PVP/EuL4/3L(phen)•2H2O by a combination of elemental analysis, inductively coupled plasma-atomic emission spectroscopy (ICP-AES) and Fourier-transform infrared spectroscopy (FT-IR). X-ray diffraction analysis (XRD) has shown that the complex is a new kind of crystal whose structure is totally different from two ligands. The morphology of the complex has been investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results have shown that the complex has a rodlike crystal structure and the diameter of the rod is about 400 nm. Thermogravimetric analysis (TG) has indicated that the luminescent complex is thermally stable below 300 °C. Photoluminescence spectra (PL) have revealed that the complex can emit Eu3+ characteristic red fluorescence under ultraviolet excitation.

Abstract: The model is generated in the paper taking the fully mechanized caving face in Yang-village mine, Yima group as engineering background, using UDEC software to analyze the influence of joint characteristics parameters on surrounding rock stability of fully-mechanized caving roadway, and from the aspects of the horizontal compressive stress between joint surfaces of roof, the roof sinking magnitude and surrounding rock failure, the fully-mechanized caving roadway is simulated with different anchorage forms and bolt length, with pallet and steel belt or not, different block sizes and different buried depths[1]. Through improved roadway supporting technology, the supporting effect was increased, the damage and destruction of the supporting to rock mass was reduced. The computed results were consistent with practical application. This shows that the technology has some directive significance for mining under the same geological conditions, and supports theoretical and practical basis for the mine's safety in production and sustainable development.

Abstract: The theoretical properties of the ARMA model and the modeling process, then, the Shanghai power network and Shenzhen power network in China were established ARMA model and wavelet-based ARMA model fitting, prediction, and finally, to fit forecast The results were compared. It can be seen, combined with relatively good forecasting effect after wavelet.

Abstract: According to the lumped mass method, the drive system of rolling mill can be simplified as a three-degree-of-freedom spring-mass model. The nonlinear dynamics equations are established considering nonlinear torsion stiffness of connecting shaft and nonlinear friction force between roller and strip, and Hopf bifurcation and critical parameters are analyzed by applying the Hurwitz algorithm criterion. Furthermore, the system stability is numerically simulated through time-history and phase plots. The results indicate that the system motion can be stable in some range of parameters, and the bifurcation phenomenon occurs and the stability may be lost across the critical points. In addition, at different bifurcation points the phase orbit run along diverse skeleton curves of revolution. These conclusions are significant to reveal the mechanism of system bifurcation and stability, and help for optimization of technology condition in practical application.

Abstract: In order to improve the design and the two-dimensional drawing identifying technology of freeform surface for the complicated components, such as turbine runner blades, based on the strong modeling technology of CAD/CAM and the software UG of CAD/CAM, detailed analyses three-dimensional modeling of turbine runner, then explain the design difficulties and three-dimensional effect of freeform surface, in order to resolve part of the design difficulties of freeform surface. Provide the original database for computer auxiliary fabricating and explain the practicability of CAD/CAM by analyses three-dimensional modeling of turbine runner.

Abstract: Bulk Fe4Sb12 and Fe3CoSb12 were prepared by sintering at 600 °C. The phases of samples were analyzed by X-ray diffraction and their thermoelectric properties were tested by electric constant instrument and laser thermal constant instrument. Experimental results show that, the major phases of bulk samples are skutterudite with impurity phase FeSb2. The electric resistivities of the samples increase with temperature rising at 100~500 °C. The bulk samples are P-type semiconductor materials. The Seebeck coefficients of the bulk Fe4Sb12 are higher than those of bulk Fe3CoSb12 samples at 100~200 °C but lower at 300~500 °C. The power factor of the bulk Fe4Sb12 samples decreases with temperature rising while that of bulk Fe3CoSb12 samples increases with temperature rising at 100~500 °C. The thermal conductivities of the bulk Fe4Sb12 samples are relatively higher than those of and Fe3CoSb12, which maximum value is up to 0.0974 Wm-1K-1. The ZT value of bulk Fe3CoSb12 increases with temperature rising at 100~500 °C, the maximum value is up to 0.031.The ZT values of the bulk Fe4Sb12 samples are higher than those of bulk Fe3CoSb12 at 100~300 °C while lower at 400~500 °C.

Abstract: Adhesive bonding technology has become one effective joining technology instead of the traditional spot-welding especially for AHSS materials. But Adhesive bond quality inspection method is limited to the mechanical performance tests such as tensile-shear test recently and it’s time-consuming and unpractical. So a reliable and practical method for on-line identifying different bond discrepancies and assessing the bond quality is necessary in industry. Based on the thermal expansion electrode displacement mechanism during weld-bonding process, the dynamic electrode displacement method could be applied for differentiating adhesive bond discrepancies effectively through acquiring and analyzing the dynamic electrode displacement signal curves during weld-bonding process from laser displacement sensors installed onto the welding gun. Lots of experiments and analysis showed that this method is basically feasible, that is, it could identify different adhesive bond discrepancies qualitatively and accurately. So it has a good potential especially applied in production line.