Applied Mechanics and Materials Vol. 189

Abstract: This paper aims at finding the best pore density and porosity of metal foams for heat transfer, as well as the most proper operating conditions. A circulating water cooling system were designed which include micro-channel heat sink, heat exchanger, micro-pump, rot meter, electric heating rods, and conversion fans for the experiment. The comparison was made between different metal foam samples in terms of flow rate and equilibrium temperature of heating boundary. The results presented that a relatively low temperature can be achieved when flow rate is large, but at the same time the pressure drop increased. The excellent heat dissipation performance of metal foams has a close relationship with its specific surface area.

Abstract: In additional to transfer the torque safely, the coupling of the diesel generator set should also has the function of compensating the relative offset distance between the centre line of the diesel crank shaft and the centre line of the generator rotor axis. In this paper, a new type of metallic-disc flexible coupling for diesel generator set of 500kW power was designed. The working principle of the metallic-disc flexible coupling was expounded in detail, and the comprehensive force performances of the metallic-disc were also analyzed. The simulation analysis was carried out to determine the optimal numbers and thickness of the metallic-disc using ANSYS software. So, the needed torque and the coaxiality between the two axes can be guaranteed. The relevant results can provide some guidance for the improvement design of domestic diesel generator set.

Abstract: In this paper, focusing on the five-bar linkage and gear combination mechanisms which can complete a whole rotation, the Visual Basic6.0 (VB) programming language is applied to produce a set of system, which can dynamically simulate the motion of the five-bar linkage and gear combination mechanism and display the linkage curve with variable parameters. Based on this system, rules of the trajectory of the hinge point C of two links changing with the physical dimensions and gear ratio of the mechanism are studied.

Abstract: High altitude and long endurance (HALE) vehicle always adopt straight or swept configuration, which leads to the problem that the wings of UAV have high aspect ratio and are very flexible. This kind of flexible wing exhibits large deformation when aerodynamic forces are loaded on them and the structural nonlinearity should be considered. So the dynamic and flutter characteristics will be changed. In the engineering applications, the effects of structural geometric nonlinearities on the air vehicle design are the most concerns of aeroelasticity before a systematic flutter analysis for the air vehicle. because the solution for nonlinear flutter speed based on the CFD-CSD method is complex and time consuming. In this paper, we propose a simple and efficient approach that can analyze the effect of structural geometric nonlinearities on the flutter characteristics of high aspect ratio wing quickly. And a straight wing and a straight-swept wing are analyzed to verify the feasibility and efficiency of the proposed method. It is found that the effect of structural geometric nonlinearities has a strong effect on the flutter characteristic of the straight wing, but is weak on the straight-swept wing. And finally the impact of swept angle on the dynamic and flutter characteristics of straight-swept wing is also discussed.

Abstract: The structure of a 3-DOF parallel manipulator is presented. The methodologies of multiple-mode negative impulses input shaping is introduced, which can decrease the delay time of the system response while the residual vibration is suppressed. The parameters of two-mode negative impulses and positive impulses input shapers of the 3-DOF manipulator are presented. The sensitivity analysis of these input shapers are carried out through numerical simulations, and the robust of the input shapers are presented and compared.

Abstract: On account of the end splitting and dropping thread problem for domestic winding machine during tassel thread production process at present, an intelligent system with subdivision driving module TB6560AHQ and SANYO stepping motor was designed, which adopted the ATMEL89S52 MCU as the core controller. The system achieved precise control of some parameters during the course of tassel thread winding such as torque, direction of rotation, speed, cycle laps, twist, etc. It also reduced the worker’s labour intensity and improved the production quality and efficiency of the tassel manufacturing, moreover, this winding machine has the advantages of simple structure, high torque, high reliability and low cost. It can meet the various control requirements for different tassel thread winding and have a considerable market prospect.

Abstract: Through the research on drilling robot at home and abroad, this paper divides steering methods into two types: steering caused by radial motion of body parts; steering caused by deflection of the head. Based on this classification, several schematic designs of steering mechanism are proposed. Respectively, structural design and principle analysis of steering mechanisms are carried out. And steering mechanism 3 is chosen the best one through comparison from the following aspects: No. of motors in the steering mechanism, size, turning radius and control difficulty. In order to prove its feasibility theoretically, the detailed modeling and analysis are presented. The results of DOF (degree of freedom) calculation and kinematics simulation of the head point show that its motion is determined and no collision exists between the parts during the kinematical process. The relation among peak value of rollers’ trajectory H, distances from rollers to the rotation axis of the cylindrical cam r and maximum deflection angle θmax is analyzed by building the deflection model, which lays foundation for further optimization.

Abstract: Abstract. A design method of ultrasonic vibration petrol atomizer vibrator was proposed based on one-dimensional elastic vibration theory. The model and harmonic analyses of the vibrator were performed by using the FEA software ANSYS. Experimental Study of the petrol atomizer was carried out and the atomization performance of the prototype was verified.

Abstract: The project designed the rebar cutting machine which commonly used in the construction industry. The main working principle of the rebar cutting machine is that the motive power provided by the motor, after reducing the speed through the primary belt transmission and secondary gear transmission decelerator, it will drive the crankshaft rotating, and the crankshaft drives the connecting rod to make the slide and moving blade do the reciprocating linear motion in the slipway, and select the crank-slider mechanism as the mechanical actuator. In order to cut rebar, we will make the activity blade and fixed blade staggered.

Abstract: According to the norms “the fatigue strength assessment for hull structures in 2007” issued by China Classification Society, the combined computing platform established is composed of mature hydrodynamic software SESAM from Det NorskeVeritas(DNV)and MSC.PATRAN/NASTRAN, the fatigue strength assessment for hull structure of a steel fishing vessel is studied.