Applied Mechanics and Materials Vols. 110-116

Abstract: Multidisciplinary Design Optimization (MDO) of a two-stage Small Solid Propellant Launch Vehicle (SSPLV) by simulated annealing (SA) Method is investigated. Propulsion, weight, aerodynamic (geometry) and 3degree of freedom (3DOF) trajectory simulation disciplines are used in an appropriate combination. Suitable design variables, technological-functional constraints and minimum launch weight objective function are considered. To handle constraints augmentation of constraints to cost using penalty coefficients are used. Results are compared with gradient-base method that shows the ability of SA to escape local optimums.

Abstract: The use of woody biomass gasification based power plants to generate electricity is on the rise with the fast depletion of fossil fuels and ever increasing energy demands. An important sub-system of such a plant is the drier which is used to reduce the moisture content of biomass to an optimum level for trouble free and optimum performance of the gasification system. This work concerns with the design, development and implementation of a drier system which utilizes waste heat available from the power plant to dry biomass. The drier designed is simple yet effective in capturing the waste heat from the engine exhaust as well as the radiator hot air. The drier is also easy to implement in rural areas.

Abstract: The relationship of contact width and leakage had been found as design concept to optimize new metal gasket. By using this design concept, the limits of contact width for no leakage can be chosen. The optimize gasket shape can be developed by increasing of contact width. In this study, a gasket shape was optimized based on contact width as design concept and involving contact stress consideration. The design of experimentation (DOE) Taguchi method is used to analyses the effect of each parameter design and predict optimal design of new 25A metal gasket. The L18 orthogonal array was concerned to design experimental matrix for seven factors with three levels. The optimum design of gasket at 0 MPa mode is the model with OH = 4 mm, p₁ = 3.5 mm, p₂ = 4 mm, p₃ = 4 mm, t = 1.2 mm, R = 3.5 mm and h = 0.4 mm. The optimum design of gasket at 400 MPa mode is the model with OH = 3 mm, p₁ = 3.5 mm, p₂ = 4.5 mm, p₃ = 4.5 mm, t = 1.8 mm, R = 1.5 mm and h = 0.3 mm.

Abstract: This paper presents the control system development of a diffraction grating ruling engine. The grating ruling engine which consists of a ruling subsystem and a indexing subsystem including a outside stage (coarse stage) and a inside stage (fine stage) and which realize groove densities of 6000 grooves/mm, maximum ruled area of 300 (groove length) × 300 (width) and nanometer level positioning error has been designed. The ultra-precision requirement demands not only precision mechanical structure but also advanced control system, both of whose development take long time. To shorten development period and reduce the costs, concurrent control system development combined with MATLAB/Simulink is implemented. The control software constructs graphic user interface to show the virtual grating ruling engine and provides interface with Simulink module. Various control algorithms, which are written in C language to facilitate future code porting, is verified in Simulink. Finally, single neuron PID control algorithm is adopted. The control software starts Simulink simulation and emulated data which is transferred from Simulink to software is used to control virtual engine to move corresponding. After the completion of simulation, the algorithm is ported into software to control the real ruling engine. The simulation and experimental results demonstrate that combined simulation is an effective approach and that the positional accuracy has been readily achieved within 9.2 nm.

Abstract: In most of the companies heavy loads were moved either with help of cranes or conveyors. The conveyors are cheaper and it is suitable for small scale industries. These conveyors are constrained and can move the load in only one direction. In this project an effort has been put forth to design a multidirectional conveyor with help of ball bearings which can handle the load at different directions. Floor conveyor consists of ball bearings & shaft that makes the load to move at any directions. In olden days logs were used to move heavy loads from one place to another we developed those concept further and found conveyors, further improvement leads to the floor conveyor with multidirectional movement. Multidirectional is achieved by amalgamation of two ball bearings which is connected by a small shaft.

Abstract: The development of the Toyota Production System (TPS) based on principles of lean technology has especially impressed numerous manufacturers around the world. It attaches remarkable importance to reducing and then eliminating waste and focusing on added-value activities. Lean technology is growing in important and scope because they help companies become more competitive and streamlined at a time when competitive and cost reduction pressures have intensified. Accordingly, a studied furniture company intends to transform its shop floor first to lean system. It is really an interesting and practical case study, so this paper presents an implementation of lean technology in an in-plant manufacturing system through a systematic way, step by step. It could be considered as a reference of an implementation of the lean technology.

Abstract: A finite element model for supercavitating underwater vehicles is developed considering the effects of the connection surfaces of cabins and the non-structural mass distribution on the structural dynamic characteristics. The frequency response of supercavitating underwater vehicles is investigated, and the performance of the configuration with flanged connections is compared to those of the configuration with sleeve connections. The flanged and sleeve configurations are then optimized while minimizing the mass of the shells and the centre-of-gravity coordinate in the axial direction respectively. The computational results indicate that at high frequencies the optimal sleeve configuration is advantageous to minimize the mass of the shells, while the optimal flanged configuration is beneficial to minimize the centroid coordinate in the axial direction, and at the same time determining the appropriate connection configuration depends on the confinement of the constraint conditions at low frequencies.

Abstract: A building security management system based on single board computer is currently under development. In this paper, a part of the system which is an automatic door access system using contactless smart card for identification is discussed. Running test shows that the system is working as expected. The system can identify multiple users each with different card. More specific access such as access by day, hour, even minute can be implemented. Alarm is used as indicator if the door is unlocked or any forced intrusion is happening. The corresponding system is going to be integrated in a building security management system to provide safer work environment.

Abstract: A Progressive die is used to transform flat strips of sheet metal into a formed part. This transformation is performed progressively by a series of stations that cut and bend the material into a desired shape. The progressive dies reduce the time and cost of producing complex sheet metal components. The design and manufacture of these dies are difficult. CAD/CAM systems have been proved very useful tools for this task. In this paper, a new system for design of the piercing and bending progressive die is described. In this system, piercing and bending operation are separated and the sequencing of each type is done individually. In this system first sequence of the piercing stations are determined then bending operations are sequenced based on a classification and fuzzy algorithm. Also, neural network systems are used to determine final angle of bends and die parameters. The capability of the system is shown using a sheet metal component.

Abstract: We propose an approach, integrating Bayesian level set method with modified marching cubes algorithm for brain tissue and tumor segmentation and surface reconstruction. First, we extend the level set method based on the Bayesian risk to three-dimensional segmentation. Then, the three-dimensional Bayesian level set method is used to segment solid three-dimensional targets (e.g., tissue, whole brain, or tumor) from serial slice of medical images. Finally, the modified marching cubes algorithm is used to continuously reconstruct the surface of targets. Since each step can definitely obtain an appropriate treatment by statistical tests, the tissue and tumor segmentation and surface reconstruction are expected to be satisfied.