Applied Mechanics and Materials Vol. 607

Abstract: The flow characteristic and differential pressure-flow of inlet blockage fault and trouble-free for control valve are numerical simulated by CFD. The study shows that relative gain of flow characteristic curve for inlet blockage is increased, and it enhances the influence on fluctuation to flow change. The flow is less than the trouble-free at the same pressure, and with the increase of the differential pressure, flow difference of comparing with trouble-free increases gradually.

Abstract: Conventional wet gas separators are used as a means to remove free water using the gravitational settling and momentum principle. However, these separators possess setback in terms of its efficiency. Alternatively, supersonic compact wet gas separators have been designed in Universiti Teknologi PETRONAS Gas Separation Research Center (UTPGSRC) which uses supersonic flow to separate natural gas and free water. In its preliminary design, determination of the flow behavior according to the design of the separators is important. The result provides information whether the design can be accepted or improvement should be taken into consideration. It is therefore an objective of this paper to numerically simulate and analyze the flow characteristic such as velocity, pressure and temperature distribution correlating with the separator design. From the flow performance results obtained, it shows that the separator design has fulfilled the requirement.

Abstract: In laparoscopic surgery, many problems are due to the poor degrees of freedom (DOF) of movement in controlling the forceps and laparoscopes. This paper proposes a new flexible laparoscopic forceps manipulator using synchronous belt drive mechanism, which consist of two miniaturized parts, synchronous belt drive mechanism enables independent bending procedure from-90° to 90° at the tip of forceps, and friction wheel mechanism which provides pivoting motion of forceps around incision hole on the abdomen. This mechanism is simple with high rigidity and can easily be miniaturized. The most remarkable characteristics of the prototype described in this paper are: 1) the casing diameter of the forceps is 5 mm; 2) with high rigidity and the repeatability positioning accuracy was 0.5o in bending motion; 3) pure mechanical structure with simple operation and low cost. This manipulator can solve the conflicts and blockings in laparoscopic surgery by switching back and forceps towards, meanwhile, it eliminates the surgical doctor’s fatigue and enhances the precision of surgery with higher effectiveness and safety as well.

Abstract: Based on the theory of spherical stability and piezoelectric motor drive with the combination of two dimensional stabilization platform. For two-dimensional motion spherical stabilized platform overall structure, having pitch and azimuth two ways. Using the theory of mechanics and geometry to mathematical modeling, prove multiple piezoelectric motor synergy drive, to achieve two-dimensional stabilized platform smooth movement. The design method and mathematical model analysis methods put forward by two-dimensional stabilized platform have important reference value to similar equipment research and development, important innovative progress has been made in structure, layout, and control methods.

Abstract: A new type of tidal unit-vertical shaft tubular turbine is designed with high efficiency, large flow rate and low water head ,which has large power under the 2~3 meters water head. According to the data of the being installed tidal units and principles of tubular turbine’s design, the high efficiency vertical shaft tubular turbine was designed under large discharge and low head, which was suitable for the tidal power station. The design also considered the requirements of turbine’s size and the details of flow through the whole flow passage were attained. The turbine’s property was predicted by the 3-d numerical simulation software on the whole flow passage. Moreover, the influences of vertical shaft’s sizes were analyzed. And the terminal of vertical shaft with or without transverse brace and longitudinal brace were analyzed to get the influence. Considering the hydraulic performance of various methods, the best guide vane opening was chosen. The results show that, the turbine unit has the best performance on efficiency, hydraulic loss, etc. with the guide vane opening 62°, meeting the power station’s design requirements. The results show that the optimal designed flow passage’s efficiency reaches up to 88.4%, the flow rate becomes much larger and the power reaches 174.63kW. Without partial vortex, the flow pattern is smooth through the whole passage also with lower hydraulic loss.

Abstract: Automated Guided Vehicle is a mobile robot used in various industries to transfer goods and materials from one place to another in the industrial compound such as production line and warehouses. Due to the payload it should carry, the design should be able to handle certain level of mechanical stress. The optimization study is important to assure the material and design is safe an optimum under the specified conditions before the AGV is manufactured. In this study, a conventional AGV designed previously by an AGV manufacturer to bring a payload of 70 kg is analyzed using the Finite Element Method (FEM) and SolidWorks software is used to do the FEA simulation. This paper also explain on how the factor of safety for the AGV is derived. The parameter change in this study were the thickness of the sheet metal used to build the AGV while the study output is the stress level, factor of safety and weight of the AGV.

Abstract: Aiming to the layout structure design and performance prediction for globoidal cam machine, a dynamic performance prediction method for machine layout structure is proposed in this paper. With the method, the motion transmission and layout structure are determined based on the mapping rules between function and structure. The prediction model for dynamic performance is established based on BP neural network, which is used to optimize the dynamic performance of layout structure for globoibal cam machine.

Abstract: As a new type planetary gear device, swing movable teeth transmission is used to transmit rotary motion and power between two shafts with same axis. It has compact structure, a large range of transmission ratio, strong carrying capacity and widely used. According to the principle of gear meshing, it was analyzed the principle and characteristics of the swing movable teeth transmission. Based on the structure was designed, after the entity modeling of the parts and the virtual assembly of the transmission are established, the virtual prototype modeling of swing movable teeth transmission was carried out by Solid Edge software. Virtual prototype modeling of transmission would provide the necessary for the force analysis and performance simulation.

Abstract: In this paper, the simplified approach using commercial computer software code was adopted to predict the performance of a kettle typed shell and tube heat exchanger. Similarly the numerical analysis using ANSYS/CFX is conducted for the same design and the result data are collected to analyze its performance numerically. In general, the heat exchanger performances are evaluated by predicting the temperature difference and pressure drop. The result data of both the analysis are compared to find the differences between the data. From the comparison, we came to know that the error percentage between the two analysis results is very low which is acceptable proving our design is convincible. Thereby we fabricated a prototype model of shell and tube heat exchanger (kettle type) with the same parameters used for these analyses.

Abstract: A hybrid graph and rule-based method for recognizing machining features is proposed in this paper, which aims to get the machining feature in 3D in-process model construction system. Initially, the attributed adjacency graph (AAG) of the input MBD models is constructed and represented in matrix form. After that, by deleting the convex edges of the AAG, the concave sub-graphs are generated. For obtaining the volumetric features, their concave sub-graphs are matched with the feature template graphs in a pre-defined library; for those which can be generated by sweeping the edge loops, such as open pocket, closed pocket, through pocket and slot, their features are recognized by using rules. In experimental section, an example is given to illustrate the validity and effectiveness of the proposed method.