Vol. 24 No. 1 (2009)

Any rolling bearing defect has a certain vibration response signature which can be observed through its waveform as well as frequency spectrum, such as the sideband frequencies, which indicate there is modulation phenomena among the vibration response signals. This research was carried out to study the vibration response signatures in the roll bearings due to the interaction between the static load and bearing inner/outer race waviness. This experimental research consists of FRF (Frequency Response Function) measurements to obtain the dynamic characteristics of the rolling bearing vibration,…

In this paper, an approach of the formulation for Hertzian contact problem between wheel and rail is presented. This formulation used analytic and numerical approach, especially in solving elliptic integrals in order to obtain dimension relations of the contact, deformation, contact pressure and stress contours. The main curvature radius range of the smaller rail are from 300-260 mm. Modeling with finite element solution was also performed as an alternative approach solution to the contact pressure. Besides, it is with Finite Element Method (FEM) can show the contact stress distribution and…

In conceptual aircraft design phase, the aircraft configuration and several design variables are frequently changed and starting points are depended on any most probable design conditions. Therefore, it is required a design tool having flexibility to response to different starting points. The implementation of the constraint propagation supported by an object-oriented programming could result in a computer application that considerably accommodates the need of flexibilities. Moreover, the implementation of some graphical user-interfaces and filter are not only to make it become user-friendly…

A gas saver for gas cooking stove has been investigated, designed, and tested in this work. The device is a conical vertical cylinder placed around the cooking pan. The application of the device does not need any modification of the cooking stove nor the cooking pan. The temperature distribution of hot gas around the cooking pan is computed by means of numerical method. It is found that a significant fuel saving can be obtained using the gas saver because the vertical wall becomes an energy input area to the cooking pan which is not the case in absence of the gas saver. The tests of gas saver…

Vertical jump is a good indicator for success in sports that need strength and speed of lower extremity such as basketball, volleyball, and soccer. The skeletal model of human body is treated as a two dimensional multibody system to analyze vertical jump. The squat jump of a particular subject could be simulated on the multi-body system model. The simulation results in the maximum jump height in close agreement with the height obtained via the flight time method analysis. Hence, the simple multibody model is deemed adequate for squat jump analysis. Furthermore, the results of this research…

In general aircraft are classified into two major categories: fixed wing and rotary wing aircraft which are commonly known as helicopters. The vertical take-off and landing (VTOL) aircraft is designed to be capable of both flying horizontally like a fixed wing airplane and also ascending and descending vertically and thus eliminates the need of a runway [1],[2],[3],[4]. At recently years, Ducted fan VTOL is most popular. The reason behind that fact is the efficiency of power on the maneuver. This paper presents the results of design and testing of coaxial rotor ducted fan VTOL UAV. Pitch and…