Applied Mechanics and Materials Vol. 842

Abstract: In computational fluid dynamics (CFD), the physical domain is usually discretized by using mesh/grid, cells, nodes or particles generation. Although there are many advantages, these methods are required to have high computational storage/time cost, especially for solving the complex, deforming, and moving flows/bodies. Hence, we developed the vortex-in-cell (VIC) algorithm which is hybrid combination of grid-based and mesh-free method. VIC method, which was originally developed to simulate incompressible single-phase flows, becomes a very promising alternative for simulating complex flows. In addition, to simulate flows over deforming geometries, we utilized an immersed boundary method for enforcing the boundary condition. VIC interpolates the particle strength to an underlying mesh. VIC method has the advantage that the Poisson inversion can be accomplished by Fast Fourier Transform (FFT) techniques, this accelerates the computational time and provides accurate results. Here we consider an anguilliform swimming motion based on lateral displacement of the “backbone” which describes a complex, deforming, and moving body. “Flow over an Impulsively Started Circular Cylinder” problem are also simulated to validate the developed numerical method.

Abstract: Integrated avionics architectures offer advantages such as higher flexibility, reliability, simplicity, future upgradeability and weight saving over previous federated designs. Successful implementations of integrated modular avionics (IMA) are onboard Boeing B777, B787, Airbus A380 and A350. These applications often result in development and maintenance cost not suitable for regional and general aviation aircraft. One popular approach to overcome this problem is by using integrated flight deck (IFD) supplied by avionics manufacturers such as Garmin or Honeywell. These manufacturers often optimize IFDs for applications in developed countries. For example, with the development and widespread use of satellite-based global positioning system (GPS) in the US, Canada and Europe, some terrestrial navigation equipment (e.g. ADF and DME) are no longer included in the standard IFD packages offered for commercial aviation. However, many areas in the rest of the world still use and rely largely on the availability of the ADF, DME, etc. Aircraft flying in these areas need to comply with the local requirements for terrestrial navigation systems already deployed. In this paper a study on the implementation of additional avionics equipment on Garmin G1000 for advanced regional turboprop aircraft is presented. G1000 is an integrated avionics system that integrates many electronic components including navigation, communication, course, attitude, display, etc. It has been widely used in all kinds of civil aviation aircraft. In order to conform to local and modern requirements, ADF receiver, DME transceiver, traffic alerting system and weather radar need to be integrated. Preliminary reliability analysis using fault tree method is performed for the designs to ascertain their safety as set out in the requirements for advanced regional turboprop aircraft.

Abstract: Coconut Methyl Ester (CME) is the main feedstock used for biodiesel in the Philippines, As of this year only 2% of CME is mandated to be blended in locally distributed fuel, but by 2016 the target is to increase the mandated biofuel blend to 5%. Given the mixed results about the effect of biofuels blends in engine perfomance by various studies it is imperative to further assess the impact of the target biodiesel blends. The effect CME Biodiesel blends in the performance of a light duty automotive common rail direct injection engine is determined in this study. Total of six fuel blends – B0 (Neat Diesel), B2 (2%CME, 98%B0), B5 (5% CME, 95%B0), B10 (10%CME, 90%B0), B15 (15%CME, 85%B0) and B20 (20%CME, 80% B0) were tested for performance at 100% load with varying speeds from 800 RPM to 2400 RPM at an interval of 400 RPM. At this typical engine speed range, no significant differences for biodiesel blends versus neat diesel were observed for torque.

Abstract: Crashworthiness is one of the most important criteria in vehicle market. A good crashworthiness avoids being injury for the passenger. There are many accidents happen every day, the most dangerous collision is in horizontal. It can make the passenger injured or died easily, because the distance from body frame to passenger in cabin is very narrow. Therefore, this study is conducted to explore the behavior of top – hat and double - hat structures subjected to three – point impact bending by using analytical and numerical methods. The length of flange is not effected to bending resistance with the same perimeter of top-hat structure. The mean force of double – hat section is higher than the top – hat so that the capability to absorb energy of double – hat structure is better.

Abstract: This paper presents the flight dynamics simulation and analysis of a tilt-rotor vertical takeoff and landing (VTOL) aircraft on transition phase, that is conversion from vertical or hover to horizontal or level flight and vice versa. The model of the aircraft is derived from simplified equations of motion comprising the forces and moments working on the aircraft in the airplane's longitudinal plane of motion. This study focuses on the problem of the airplane's dynamic response during conversion phase, which gives an understanding about the flight characteristics of the vehicle. The understanding about the flight dynamics characteristics is important for the control system design phase. Some simulation results are given to provide better visualization about the behaviour of the tilt-rotor. The simulation results show that both transition phases are quite stable, although an improved stability can give better manoeuver and attitude handling. Improvement on the simulation model is also required to provide more accurate and realistic dynamic response of the vehicle.

Abstract: One of many solutions that can be applied to solve the transportation problems in Yogyakarta is by adding another mass transportation system which is eco friendly, ergonomic, and does not cause congestion and accident in the highway. There are several kinds of mass transportation that can be developed in Yogyakarta, such as monorail, tram, even commmuter line. But considered from the various advantages and disadvantages, the monorail is an additional mode of transport that is most suitable for Yogyakarta, because its railways are not become one with the road like a tram that may caused another negative impact. The main orientation of this design is to make a monorail body carriage. In designing this monorail body carriage, the conditions of design follows the model and carriage capacity that applied by urbanout with the operating condition data including the size of the carriages, passenger capacity, speed of the train, and the wheel base distance. Aluminum alloy 6061 material is used in the design of the carriage frame. And then the forces working on the carriage is calculated. The magnitude of the forces working on the carriage must be able to be endured by the frame. Data from the design then simulated with static load simulation using Autodesk Inventor 2012 software. From the analysis results will be seen whether the design of the carriage frame structure has been made safe. The size of the carriage is 8800mm x 2350mm x 3100mm for the front and rear car and 6700mm x 2350mm x 3100mm for the middle car. The results showed that the structure of the carriage from urbanout model with frame made of aluminum alloy 6061 is strong enough and suitable for use in light monorail vehicle. With the smallest safety factor by 4.56.

Abstract: Application of optimization method for structure design and analysis is a technology trend to provide optimum products. This paper describe optimization process using genetic algorithm that was applied on non traditional structure, geodesic beam element. Finite element method program was developed as a main computer code for supporting optimization process. Pre-and post processor program was created to support GA. Based on minimum structure weight as the target of design optimization, the number of beam, beam element angle, and its size are to be the output of optimization process. The geodesic structure weight of plane model have been compared with traditional structure, and the results show that geodesic structure provide better performance of responding load direction than traditional structure. The influence of swept angle to the weight structure show that the higher the swept angle of geodesic beam structure, the higher values of weight structure are resulted.

Abstract: This paper presents an analysis of spectral error analysis of windowed discrete sinusoidal signals. The objective of the work is to understand how window functions affect the discrete frequency spectrum and how to minimize spectrum errors. The spectral error analysis, in which the mathematical expression of the spectral error is derived, is conducted to a discrete sinusoidal signal with single frequency. The analysis reveals the fact that the applied window functions will produce peak spectral error regardless of the sampling rate and recording time. This result has been confirmed through numerical simulations. In addition, an experiment is conducted to investigate another type of spectral error, which is frequency error. The frequency error can be minimized by collecting more samples in signal measurement process, which means the recording time is increased, even though this effort does not improve the amplitude accuracy.

Abstract: This study focuses on the development of a quadrotor research platform with effective obstacle avoidance system using Bug Algorithm. The quadrotor system consist of a DJI frame with a Crius All-in-One Pro as a flight controller with an Arduino Mega2560 to process the data from the sensor. It is also equipped with four ultrasonic range finders to provide the sensing for collision avoidance. Bug Algorithm was chosen due to its simplicity and effectiveness in implementation of obstacle avoidance applications. The results shows that the quadrotor system is able to perform basic flight maneuvers and that the collision avoidance system was able to protect the quadrotor from hitting objects in its environment.

Abstract: The green technology is applied in training welders by using simulation equipment. The virtual tungsten inert gas welding (TIG welding) equipment permits of reducing the cost of welding practice training by saving on materials, electricity. It does not cause the environmental pollution. It is not harmful to welding learners. This paper studies on the permissible range of technological and technical parameters of TIG welding process. This is basis to develop the software in order to evaluate learners on virtual TIG welding equipment. These are foundations to manufacture the virtual TIG welding equipment. This equipment allows welding learners to practice the basic operations and skills as on real TIG welding machine, including the techniques of striking the arc, restarting the arc, maintenance of arc length, controlling of torch angle, filler rod angle, the operations of torch move, filler rod move,... with different welds and different positions