Applied Mechanics and Materials Vol. 761

Abstract: A current study regarding the development of a rehabilitation device for lower extremity is presented. The device is specifically designed for rehabilitation of post-stroke patients who encounter walking weakness. The rehabilitation device is categorized as an active device that is power-driven by a DC motor. Its design was the outcome of improvements to counter the problems existed in the a newly developed prototype. A motion simulation was used to ratify the motion capability of the proposed design in the modelling design process. Analysis of kinematic and dynamic behavior of the motion simulation has been carried out. The smoothness of the mechanical movement and the linear velocity provided by the device are acceptable as additional work of the design process. Based on a statistical analysis, the study found that there is no significant difference from the motor torque requirement even though the angular velocity of the motor was changed substantially.

Abstract: Warpage deflection is one of the common pitfalls in plastic injection moulding which is always affected the quality and accuracy of the plastic products. It occurs due to the influences of mould temperature during injection moulding process and it is related to the number of cooling system existed in the mould. Therefore, this paper studies the effect of cooling channels on warpage of dumbbell plastic part having different number of cooling channel using Moldflow software. Warpage analysis was run using four and eight cooling channels. Parameters involved in this study are injection time, packing time, melt temperature and mould temperature. The result of warpage from simulation analysis was projected on the graphic having different colour which is presented the actual value of warpage. It is found from warpage simulation result that the maximum warpage for four cooling channels is 1.283mm and the maximum warpage for eight cooling channels is 1.280mm. It shows that the increasing of the number of cooling channel from four to eight channels in the injection mould reduces the warpage deflection about 0.2%. Thus, the result shows that the number of cooling system in the mould plays an important role on the quality of plastic part during injection moulding process.

Abstract: The interests in multiphase (more than three) system are escalating recently especially in the motor drive applications. Thus, this paper introduces the graphical phasor diagram method in designing the multiphase transformer connection. The proposed method eases the design process of the static multiphase transformer that produces multiphase output from the standard three phase input. The transformer connection was simulated in ANSYS Maxwell and the multiphase waveform with appropriate phase angle was obtained. The design of five-phase transformer using graphical phasor and simulation results from the finite elements software are presented in this paper.

Abstract: The main objectives of this paper is to find the way for solving the problems of aluminum extrusion process, and improve the mechanical properties of the products through a smart design, modelling and simulation of this process by using finite element method (FEM). For the purpose to model a (2D) two dimensions warm aluminum extrusion process, ABAQUS software was used to set up the finite element simulation. The main parameters which have major effects on this process like extrusion stresses, temperature, and die geometry, i.e. extrusion radius, were taken into consideration. Aluminum alloy (Al-2014) was used as the billet material, with 40 mm diameter and 75 mm length. It is important to preheat the billet from the beginning to a specific temperature, and then pressurizes it into the die. This process is an isothermal process with an extrusion ratio of 3.3. Subsequently, the optimized algorithm for these extrusion parameters was suggested based on the simulation results. The results suggest that the large die angle needs a less extrusion load than the small die angle. In all die geometry used, the deformation of aluminum billet, which caused by shearing and compression stresses, happened in a small sectional area, i.e., bearing area. The results also showed that the values of these stresses can increase or decrease depends on the die entrance angle and the die bearing length. To avoid the effects of these stresses on die dimensions; the hardness, material selection, and geometry should be well calculated.

Abstract: The automotive development process is advancing through the utilization of CAD/CAM/CAE. This advancement is being enhanced by proper utilization of CAD/CAM integration, Digital prototyping and Digital mock-up. Until recently, CAD has played the leading role for the digitalization of automotive development. However, recent trend shows that, the leading role is shifted from CAD to analysis simulation. Three-dimensional design, which utilizes digital mock-up, is becoming the main tool for product design. Here, the functional capability and predictive assessment by CAE is the core technology. In addition, this supporting role is helping to realize the concurrent engineering in production engineering field.

Abstract: A numerical study of the turbulent flow in an orifice plate within a pipe is carried out by utilizing the Navier-Stokes (N-S) equations. The governing equations are solved using primitive variables with a finite volume method (FVM) and simulated using the finite volume based commercial CFD code ANSYS. The study investigates the influences of Reynolds numbers (Re = 5000, 10000, and 15000) and aspect ratio (β = 0.2, 0.3, and 0.5), on the flow characteristics, i.e. the velocity profile, the differential pressure, and the vorticity, and on the mechanical properties, i.e. the strain, the stress, and the total deformation of the flow around and beyond the orifice. It is found that as the Reynolds number increases, the flow velocity and the pressure increase. The vorticity images show a slightly different behavior. As the Reynolds number has its own effect on the results, it is also found that the aspect ratio affects the results more significantly. The flow patterns are presented for unsteady flow throughout the orifice plate at different values of the Reynolds number.

Abstract: Throughout the production process, improper planning and exploitation of the CAD/CAM system leads to the low level utilization of the CNC milling machine. In product design, tangible prototype is fabricated using CAD/CAM techniques in the design phase to analyse and modify the product before actual production. In this research, industrial clay is used as the prototype material. The objectives of the study are to investigate the machining parameters of industrial clay using the CNC milling machine and to apply the CAD/CAM system in producing a clay sample part via the CNC milling machine. Using uncomplicated and low cost setup for the fabrication method, an industrial clay sample part is prepared in the CAD/CAM system and shaped using the CNC milling machine. The difference between the simulated and the actual machining time of the machined part is analysed.

Abstract: The purpose of this study is to develop a database for checking fixtures for automotive parts. The parts used in the fixture checking process were automotive parts such as clamper, stand and toggle. The goal of this project is to implement a database of checking fixtures parts. The project started with identifying the current problems that were faced by the designer at a design department, in a support service for automotive industries. Idle time has been the major problem that designer have to faced. All the data and information related to this project has been sought and explored in the literature review. Catia software is used as the CAD software to construct three-dimensional models for the design of all the parts in the parts library. All the parts are organized in three different sizes which are determined by the size of car body panel. Referring to the result, new libraries were developed and created using the Catia software to aid designers in the checking fixture design process. The validation of the new libraries had been conducted with the company’s design engineer to test the effectiveness, usability and relevancy. In summary, this database and method can potentially accelerate the checking fixtures design process to be faster and more efficient.

Abstract: The effect of mould temperature on warpage using water and oil as coolant fluid was studied using flow software analysis. Mould temperature was controlled using two types of coolants; where cold mould was controlled by water and hot mould was controlled by oil. The simulation analysis was performed using flow software analysis Moldflow Plastics Insight (MPI). Taguchi method was used to design the planning matrix and to find the optimum levels of input variables. Then, to find the percentage contribution of input variables on output variables, analysis of variance (ANOVA) was used. It is found that mould temperature controlled by water shows less warpage analysis compared to oil. The minimum and maximum percentage of warpage analysis between cold mould and hot mould are 3.1% and 7.1% respectively. In addition, ANOVA analysis shows that the most significant parameters affected the warpage analysis for both moulds using oil and water are melt temperature (255°C) followed by mould temperature (water 15°C and oil 70°C) and cooling time (water 8s and oil 6s). Thus, it shows that coolant medium used in mould cooling system contributes the quality of plastic parts.