Key Engineering Materials Vol. 572

Abstract: The Mechanical and Technological Innovation Centre (CDMIT) of the National Autonomous University of Mexico has a research area focused on the design of upper limb prosthesis. A large number of prosthesis have been developed and tested. This paper presents the analysis made to different proposals of myoelectric hands based on TRIZ. Two TRIZ tools were applied: The Innovation Situation Questionnaire (ISQ) and the Radar of Evolution. The analysis was made in terms of time, space and the user interface. The ISQ helps to better define the scope of the problem through six basic questions; each question provides a different view of the problem. The radar of evolution helps to make a selection of trends of evolution depending on the product or system, as an analogy of a benchmark. The analysis was made considering the state-of-the-art hand prosthesis: i-limb, be-bionic, Michelangelo and Myohand against the prosthesis prototypes developed by the CDMIT. The result of this tool is a diagram that reveals the level and opportunities of evolution. These opportunities imply a strengthening of research areas not only in the CDMIT but around the world. The conclusion achieved is that different design paradigms linked to bio-mimics criteria are needed to design more innovative user-friendly prosthesis.

Abstract: The matching method is used to select the most similar modular design scheme from the history product database. The existed methods are not efficient enough. A new matching method based on the gray theory was presented. The absolute correlation degree and the relative correlation degree between the target modular product and the history product were calculated respectively, and finally the comprehensive correlative degree was gotten, the most similar historical product was matched. In the end, the approach is illustrated with a hydraulic turbine case.

Abstract: With the increasing technological advances, people need more goods and services especially in consumerist societies. This increase in consumption along with technological advances leads to increase in the variety of peoples taste. Therefore, furniture companies try to design their products based on their customers needs. This study examines the factors that affect the furniture sales in high-income segments of the society. 42 students including 23 women and 19 men between 20 to 38 years, attending Kish International Campus at Tehran University, fill out questionnaires related to the beauty, comfort, color, quality, durability, price and brand of their preferred furniture. All data were collected and analyzed using statistical methods. Furniture with symmetric shapes are more desirable (p<0.0001) than asymmetric furniture. Wooden furniture has the highest demand (36%) while metallic furniture has the least demand (8%). These results showed users preferences and factors that affect the furniture sale in high-income families. Such studies can help adapting furniture design based on costumers need and may lead to improve companies furniture sales.

Abstract: This paper proposes the study of innovative packages based on a new folding technique namely crumpling. This technique consists in creating a network of complex 3d crease patterns according to a crumpling process that generates random folds from a single flexible sheet. In order to understand the topological and geometric properties of crumpled structures, a hypergraph method is proposed. The graph gives a trajectory of the geometric and topological changes of the crumpled structure during the folding process and highlights some fundamental crumpling operational sequences.

Abstract: The purpose of this work is to present the study of the technical feasibility and functional design of an interchangeable mini head extruder based on a screw with variable section to be used in open-source desktop 3-D printers. The QFD matrix was used during the design planning where the non-commercial users’ requirements were established. Functional structure of the mini head extruder was organized to give support to the mechanical calculation. The choice of a feasible configuration allowed the pre-calculation of the main components of the proposed head which were: screw, barrel and motor system. The materials chosen for the mechanical and rheological calculations were polyamide and the biopolymer PCL, both in powder distribution. Apart from the mechanical design, supported by the QFD, and functional analysis, the mini head extruder was manufactured and assembled, showing its functionality to generate filaments with diameter of 0.7 mm from powder raw material. The complete mechanical and electrical design development and manufacturing of this mini head extruder were made in a period of 24 months. This systematic development demonstrated the importance of the design methodology during the development of the design process and its contribution to the design quality. Besides, the mini head extruder using screw will allow the generation of scaffold structures using biopolymers, as well as to enable comparative studies using different kind of polymers.

Abstract: ntegrating section feature recognition with forward design is an effective method to reconstruct section curve and change feature architecture patterns from 2D to 3D. This paper proposes solutions to filter the points on the slices of point cloud data, automatically sequence the points on slices, recognize section curve feature, fit each curve segment and reconstruct section curves. All the relevant algorithms are implemented in Matlab. The point cloud data of sighting scope is used to validate the strategy. Also, Error analysis is carried out in Geomagic Studio. This strategy proves its feasibility and accuracy of completing reverse modeling process.

Abstract: Recently, the shortage in fossil fuel causes the inflation around the world. Every nation is aware of the energy dependence on the imported oil and starts to invest on the replaceable energy such as fuel cell, solar cell and wind power. Besides of exploring more energy, cutting off the energy waste is another solution. However, for nearly all distribution system is AC-powered at present, the feasibility of DC distribution system should be discussed. Moreover, AC/DC converters and DC breakers which are two important components in DC distribution system are also the issues to be discussed. Therefore, in this thesis, the feasibility of DC distribution will be investigated. In addition, the feasible topologies and design rules of converter and breakers are proposed with the verification by simulation results.

Abstract: The small scale wind power generation system is connected to DC micro-grid, which is composed of the small scale wind power generation system, battery, load, DC/AC converter, DC/DC converter, bidirectional DC/DC converter and DC bus. Simulation research is done for the small scale wind turbine model which is connected to the DC micro-grid. The output voltage of boost converter will change in real time by adjusting the PWM duty cycle. The maximum power point of wind power generation system is tracked by using the MPPT(maximum power point tracking) control strategy of perturbation and observation. The simulation results of DC micro-grid show that the tracking of wind turbine maximum power point is normal in the system.

Abstract: The kinematic model of a tractor pushing an airplane without rod on the flat ground was established. Based on Lyapunov stability theory, backing up the system was proved to be an open-loop unstable problem by kinematic analysis. In this paper, we investigate the effects of different kinematic parameters on the manoeuvring stability of the system in backward-motion. The handling and stability of the reversing operation has been simulated with a steering wheel angle step input. A tractor drivers operation of correcting steering angle has been proposed according to the experiment results. Theoretical verification and experimental results indicates that it is referential to study the handling and stability of the non-rod tractor-aircraft system in backward-motion.

Abstract: Jib cranes are a kind of material handlingmachines using in the industry such as factories, shipyards, constructionareas, and storages. Standards and regulations about them are published by API(American Petroleum Institute), FEM (The Federation Europeen de la Manutention)et al. In this study a jib crane designed by an engineering work group, were examinedin terms of static structural test analysis before put it into use according tothe API Spec 2. Firstly, critical areas, which have the highest stress values,were determined by finite element method in a commercial analysis program. The nextstep is the application of strain gages on the structure and initial referencetest values are obtained just before the assembling. Two tests were done afterthe jib crane was assembled under circumstances with no load and test load.Finally, strain and stress values were calculated and the resulting stressobtained from tests and finite element method analysis results were comparedwith each other.