Abstract: A concept based upon Equal Channel Angular Extrusion (ECAE) is developed and introduced in the form of a Universal Re-usable Energy Absorption Device ‘UREAD’. In impact situations the device utilises the energy required to extrude deformable materials through the shear planes of a set of intersecting channels and hence provides the means to protect engineering structures. The impact force is absorbed through the resistance of a deformable material and the energy is dissipated through an operational stroke. This paper examines the use of this new concept under dynamic loading. The device performance and usability during dynamic impacts are tested in a landing frame type experiment where the effectiveness of the technique in reducing impact loads and energy are also examined.
Abstract: In recent years, tube hydroforming has been applied in automobile and airplane industries, to decrease weight. In general, the determination of internal pressure path is a key factor in improving the formability in tube hydroforming. One of the effective methods in improving the tube hydroforming is using the pulsating internal pressure path. In this research, hydroforming of bi-layered tubes under pulsating pressure in x-shaped die is simulated by means of three dimensional finite element method. Some numerical results were compared with experimental results and show good correlation. Influence of pulsating pressure on the thickness and stress distribution have been also studied. It was shown that pulsating pressure improves the formability in hydroforming of bi-layered tubes via continues and gradual removing returnable wrinkling which is caused by a low pressure in this process. In addition, effect of some key parameters such as friction and die corner filling have been investigated.
Abstract: In this paper, we present different points of view to make the sheet metal and micro-wave product as manufacturing friendly as possible. Within DFM(A)-research (Design for Manufacturing and Assembly), engineering design and manufacturability of Micro-Wave (MW) and sheet metal products has been studied. Other aspects of DFM(A) have risen from novel material applications and the development of CAD (Computer Aided Design) environments. In this paper, practical examples are presented to show how to apply DFMA-rules to MW- and sheet metal components, in particular, and how to develop DFM(A)-rules for these purposes.
Abstract: This research concerns the design of a presenter mouse which is currently available, and applies the theory of inventive problem solving (TRIZ) design method to carry on the improvement and design of the product. The objective is practicability and functional improvement of a wireless presenter mouse, letting it combine the principles of human factors engineering so that possible discomfort induced by long time operation can be lightened. Finally, Pro/Engineer and Photoshop drawing software is applied to finish the design drawing of two mice, one for males and one for females.
Abstract: Most of the current air compressors are driven by a slider-crank mechanism consisted of the crank, connecting rod, and piston. Complexity of this mechanism, however, restricts miniaturization of air compressors. In this study, a design based on a new mechanism, a hybrid of cross-slider and scotch-yoke mechanism, is adopted to develop an oil-free, light-weighted air compressor for portable medical devices. By eliminating the connecting rod, the mechanism has several advantages in addition to the obvious weight reduction due to the simpler mechanism such as the longer seal life of the seal between the piston and cylinder (so called Teflon cup) and reduced shaking forces. Cylinder pressure time history is obtained based on the ideal gas behavior and the isentropic process. Shaking forces and motor torque are calculated from the dynamics equation of the air compressor. The flow capacity curve of the air compressor is obtained by considering the effect of the clearance volume. An actual prototype was fabricated and tested to demonstrate the feasibility of proposed concepts.
Abstract: In order to investigate the life of bearings lubricated by solid lubricant (BLSL), which are installed in the rotational parts of spacecraft, a test platform has been developed. The platform can test the life of BLSL working under the vacuum environment with high-low temperature cycle conditions. The test platform consists of three systems of loading, measurement, and power and speed control. A corresponding computer program was also developed to measure, monitor and record test data. The working life of deep groove ball bearings lubricated by MoS2 solid lubricant was tested in 5×10-4Pa vacuum. The surface observation and analysis for the damage condition of the failed bearings were also conducted.
Abstract: A picking and steering adjustment system for blueberry harvesters has been developed. In this paper, the main hardware and working principles of the system is introduced first, then the application of an ant colony simplification algorithm in the system development is presented. Information of virtual modeling the blueberry plant images and fruit distributions is obtained through the control system which is used as input for the ant colony simplification algorithm calculation. Then results are translated into real-time travelling path planning instructions for the blueberry harvester. The research provided technological and new knowledge support for future investigations into intelligent travelling path selection, thus playing an important role in mechanization and intelligent harvesting processes for blueberry harvesters.
Abstract: The Brushless Direct Current Motor (BLDCM) has been researched by many scholars because of its simple structure, high power density, high reliability and easy control. In this paper, a driver based on the system on a programmable chip (SOPC) is designed to implement adjustable subdivision. For SPWM, SVPWM frequency conversion control Direct Digital Synthesizer(DDS) is introduced, DDS Intellectual Property (IP) core is designed for motor control of frequency conversion. This driving system can solve the high subdivision problem, increase the driving torque and angle resolution, and smooth the motor angle. Employing the bottom-top design method, the circuit was described by the VHDL language, synthesized by integrated environment, and simulated by Modelsim in both behavior level and gate level through the PLI interface. According to experiment’s result, this driver has the advantages of easy debugging, high anti-interference ability, larger driving power, low volume and low cost in large scale production.
Abstract: A firing mechanism with associated pipe for a pneumatic cannon was developed. it can make the pressure of the chamber reach the full pressure immediately in the launching process. The dynamics analysis of the control pin were carried out and kinematics equations of projectile in the launching process were developed. The strength and impact process of the accompanying tube were confirmed by the computation analysis results.