Advanced Materials Research Vols. 479-481

Abstract: Measuring the tensile strength at the suture line of walnut shell is difficult by general fixtures. In this paper, a particular fixture was designed for measuring the tensile properties of the whole walnut shell based on the Pro/E software. The rigidities of main parts were checked by theory of mechanics combined with ANSYS. The results show that all the deformations were within the permissible scope, that is to say, this design is reasonable. Besides, four adjusting levers are designed to meet the size requirements of vary walnuts whose diameter is from 28mm to 40mm. Meanwhile, it can be conveniently located on the electronic universal testing machine.

Abstract: This paper establishes the finite element model of main spindle in the test rig for high-speed railway bearing. Utilizing the finite element analysis software ANSYS, the modal analysis for spindle is carried on. Preliminary determination is that spindle resonance occurs. Structural optimization is carried out by increasing first natural frequency and reducing weight of main spindle in order to avoid resonance. The results showed that the position of support bearings is determined. The first natural frequency is increased by reducing spindle weight. The dynamic performance of the spindle is improved, avoiding the resonance region effectively.

Abstract: A quasistatic and steady state contact problems of rubber roller and rigid roller is modeled by using a stress function in the form of series. The model is derived from the paper feed unit of duplicating machine. The point interpolation meshfree method (PIM) is applied to obtain the solution of the dual series equations resulting from the boundary condition. Stress and deformation for the rubber roller are obtained based on elasticity theory. Effects of rubber thickness and normal load are observed through the numerical examples. The observation show that the contact zone is changing with the normal load F and the rubber thickness has effect on the stress distribution. In addition, the study shows that the PIM method is an efficient and promising method for simulating the problem.

Abstract: The bearing matching principles of balancing disc-type centrifugal pumps have been discussed in many textbooks. However, as far as the matching principle to be concerned, there are discrepancies between practice and theory. Starting with the working principle of balancing disc, aiming at balancing process, and combining with examples of centrifugal pumps and related query results, this paper analyzes and presents the bearing matching principles of balancing disc-type centrifugal pumps. It is expected to provide references to colleagues and marine engineers.

Abstract: For non-zero-modification spiral bevel gear, its machining parameters could be designed with big contact ratio by Local Synthesis. This design method could make up the shortage of low coincidence degree resulted by increasing mesh angle in the non-zero-positive transmission designing. Taking an example, according to comparing the new with conventional design simulation results, the max root tensile stress of pinion was reduced by 28.36%, and the max root compressive stress was reduced by 23.31%, and the max tooth surface contact stress was reduced by3.5%, and the root stress of gear was a bit decreased under the same load conditions. The conclusions showed that the pinion bending strength was improved obviously, and new tooth profile design and its machining parameters made gear pair possess higher life and reliability.

Abstract: The optimization of the structures is difficult because the variables have different physical property or different quantitative attribute. The shape and cross-section optimization of spatial grid structures is performed by an improved genetic algorithm. The constraint conditions are composed of the structural deformation, the stability of the compressive members, the slender ratios, and etc. The treatment of the constraint conditions and the optimization function gives an unconstrained analytic function by adopting Lagrange multipliers. The method enhances the running efficiency of the genetic algorithm. The programme for structural optimization containing the mixed codes of continuous real variables, discontinuous real variables, and integer variables is coded by using MATLAB Toolbox functions for genetic algorithm. The analysis of examples shows that the programme is reliable, and the convergence of the algorithm is fast as well.

Abstract: According to the technical requirements of mango picking, a set of mango picking machine devices is designed. The device applied hydraulic system, controlling transmitting movement and performing related actions. The analysis shows that the system flexible, precise positioning is indeed able to complete the required action. And it also solutes some shortage like picking difficult, a waste of time and strength during the large acreage mango harvest in Hainan and overcome the labor-intensive manual picking and the defect of low efficiency, the effect promotes the mango industry in Hainan and commercial development.

Abstract: In the present rural power grid reconstruction project ,according to the problems of capacitor reactive power compensation in rural small substation. Take a small substation for instance, according to its operation and control method, set the criterion of the capacitor bank switching. A new high reliability, flexible reactive power compensation control device based on s7-200 PLC is designed. It plays an important role in improving the power supply , guaranteeing the quality of voltage, reducing the loss of rural power gid.

Abstract: A new suspension using double-wishbone and coil spring type structure is designed for four-wheeled independent steering and driving electric automobile. Firstly, the simplified geometric model is built, and the ADAMS is used to set parametric model. Optimization design was carried out upon the suspension guiding mechanism. The design method of suspension spring stiffness and damping coefficient is presented. And the reasonability of the method is verified by simulation and experiment. The created suspension prototype complies with the design requirements. The suspension test-bed is designed, which can complete t various detection experiments during designing.

Abstract: To solve the problem of active vibration control for satellite antenna reflector, which is weak damping and closely spaced modes, the optimal actuators/sensors deployment and controller designing need to be considered. Firstly, the optimal criterions of controllability and observability are designed according to the specificity of Gram Matrix eigenvalue in satellite antenna system equations. Secondly, based on the above criterions, piezoelectric materials (as sensors and actuators) and genetic algorithm are utilized to optimize the deployed locations of sensors and actuators. Finally, to suppress the vibration of satellite antenna reflector, a Linear Quadratic Gaussian (LQG) controller is designed under the impulse and white noise excitation respectively. The simulate results show the effectively deployed locations of sensors and actuators, and the correctness of designed LQG controller.