Applied Mechanics and Materials Vols. 105-107

Abstract: An analysis was carried out to study the efficiency of straight rectangular fin with combined heat and mass transfer. Numerical solutions are obtained for fin efficiency with SOR method when the fin surface is dry, fully wet and partially wet. The effect of fin parameters including the ratio of fin width and fin thickness to fin length as well as Bix on fin efficiency were also investigated. It is found that fin parameters shows impressive effect on 2-D fin efficiency, and the critical air relative humidity becomes closer to air saturated humidity when Bix increases.

Abstract: In recent years, the self-elevating derrick substructure which with the characteristics of easy to install、remove and transfer are gradually replacing layer box, box block substructure, etc. The three-dimensional finite element model of the MXD-701 jack-up derrick and substructure, which is used to analyze static properties of the petroleum substructure under the six different working loads are built by the ANSYS finite element software. Meanwhile, the wireless structural testing system（STS-WiFi）is testing at the MXD-701 petroleum substructure. Then comparing of the model results and testing results. Analysis results indicate that the stress of the substructure at the two beam table is greatest, the stress of the upper part of the guy column is much greater, and others are low, but in general, the overall substructure can fit the requirements of the strength and intensity. The compared results can accurately reflect the project structure of the stress and strain. Then, we can get the capacity of the substructure in order to provide evidence to the security situation of the substructure. It will have great significance to enrich and develop the mast base design and safety assessment theory.

Abstract: Valve train is one of important mechanisms in internal combustion engine. The experiment is an important method to study the valve train. In the design of valve train experiment, the Permanent-Magnet Synchronous Motor (PMSM) is used as the driving force to drive the camshaft. PID controller based on compensation with repetitive control is designed to control the PMSM. It can eliminate all periodic errors in closed-loop control. And it has a virtue of nonparametric dependence on its control performance by combining with two control methods. An example has been given and simulation has been made. The simulation result shows that the controller apparently improves the position tracking precision and reduces the tracking error of servo system. So the PID control system based on compensation with repetitive control has a much higher accuracy than the PID control system has. It is fit for high-accuracy control of valve train.

Abstract: With the development of science and technology, the smaller generator was got more and more attention for people. In this article, through manufacture of single-phase and three-phase micro vibrations nanogenerator, the working principle of single and three-phase micro vibrations nanogenerator are introduced, and their performances are studied. Results show that, the pulse micro vibrations energy can be changed into rotating kinetic energy, then it can cause the rotation of the coil which produces electrical energy by cutting magnetic line. Energy conversion rate is exceed 80% for nanogenerator. Now, we can produce single, three-phase micro vibrations nanogenerator using the existing nanometer material. The power of three-phase micro vibrations nanogenerator is higher about 50% than the single one, it’s power factor is also slightly higher than that of single-phase. It indicates that three-phase micro vibration nanogenerator is better than single one.

Abstract: For the traditional automatic-generation algorithm of electronic chart plan shipping route, it is difficult to achieve the shortest route and the least turning points at the same time. In this article, the optimal and planned shipping route automatic-generation method algorithm based on the rubber band algorithm was put forward. In this algorithm, the elasticity principle of rubber band was adopted to improve the original and basic path and the shortest path and the least turning points can be achieved at the same time. The experimental results showed that the algorithm can quickly and automatically generate an optimal and safe route with good stability and high searching efficiency and so it can be applied to shipping route planning in complicated and large sea area.

Abstract: When solving Euler equations of fluid dynamics around complex configurations, a meshless method which doesn’t use the information of the meshes may have the advantages to simulate the flow field. In this paper, a simple and accurate meshless algorithm based on AUSM+ and MUSCL scheme has been described. To assess the capability for capturing shock position and the resolvability of the complex shock waves, a number of typical test cases are calculated with the meshless method. The results obtained are in good agreement with the exact solution or some high-resolution numerical method as well as flux-corrected transport (FCT) algorithm with adaptive mesh refinement (AMR) technique.

Abstract: To improve the general stability of submarine pressure hulls, this paper brings forward that redistribute the stiffness of the ring-frames according to the radial displacement of the buckling shell instead of uniform circular ring-frames. With energy methods, the formula of general buckling pressure is deducted in this paper. Some pressure hulls of different thickness with different number of frames are taken as examples. This method turns out to be effective on raising the general stability of ring–stiffened cylindrical shells by both the formula calculation and finite element analysis.

Abstract: Using the second crushing theory and combining with the single-tooth rolling mobile crusher mechanism analysis, a single-tooth rolling mobile crusher mechanical model was established. Through analysis of force on the tooth roller, deduced calculation formulas of the teeth roll tangential force, the tangential force by an example calculation was more accurate.Through the analysis of the whole crushing process, the process can be divided into three kinds of condition to analysis of roller teeth force, the roller teeth mechanics model was established under this three kind condition.

Abstract: This article simulates crack propagation problem of aero-engine blades under aerodynamic loads and centrifugal loads. Blades are critical parts in the aero-engine, fatigue fracture failure is the major failure mode for aero engine blade, one broke blade will result in serious accidents for the whole engine with great economic losses. This article finds out the location of fatigue crack source firstly according to the blade stress distribution. Then the paper calculates the stress intensity factor at crack tip for different crack length which is based on the finite element method and fracture mechanics, simulates the crack propagation path, and figures out the crack growth rate with Pairs model and FNK model .Finally this article predicts the crack propagation life.

Abstract: Pneumatic miniature robotic control system usually adopts PID (Proportion Integration Differentiation) control strategy at present. To cope with the limitations of the basic PID control strategy, an improved single neural network PID control strategy is put forward in this paper. The control strategy is a single neuron adaptive controller with adjusting weighting coefficient, the weighting coefficient is realized according to the Hebb learning rule with supervisory. Both simulation and experimental results indicate that steady state error of the system equal to zero in the step-response curve, this scheme is a feasible control method for the 3-dof pneumatic miniature robotic control system.