Applied Mechanics and Materials Vols. 773-774

Abstract: This paper presents frequency analyses of sounds produced by traditional Malay musical instrument “kompang”. Kompang is used to produce exotic sound especially certain grand ceremony. In order to produce sound, different types of skins are used especially made from polymer (used x-ray film) and animal skins. However, the sound produced by a polymeric skin is not similar with the sound produced using an animal skin. Therefore, this present work investigated the effect of such skins on the sound produced and as a result affecting the sound quality. Appropriated software is used to conduct the frequency analyses in order to investigate whether the polymeric skin can be a replaceable skin in replacing an animal skin. It is found two different skin materials have their own sound characteristics and it is also indicated that lower peak sound frequency produced by animal skin compared with the polymeric skin.

Abstract: - Concrete sleeper is the main structrural component in railways track. Concrete sleeper is used to transmit the load from the train to the ballast. In this study, the pattern of load applied to the concrete sleeper was determined. The pattern of load is important as it affecting the design and lifetime of conrete sleeper. The raw data for load of train will produced variable amplitude value as the concrete sleeper will be experiencing the different type of loading. The value of raw data when the wheel of train hit the concrete sleeper will be higher than the raw data when the conrete sleeper is experiencing vibration due to incoming train. In this study, the pattern of load will be analysed to understand the behaviour of the load applied to concrete sleeper. Other than that, the variable amplitude value of raw data will convert into a constant amplitude value using a method of calculation. The determination of constant value amplitude will be divided into N-section to finding the maximum and minimum value for the section. In addition, the actual number of cycle from the raw data will determined using Rainflow Counting method. This study can be further used for laboratory work as it’s determine the suitable loading and cycle applied to the concrete sleeper under dynamic loading.

Abstract: This paper presents a study on quadrotor using PID controller together with the application of Kalman Filter. Purpose of this project is to study effect of separate Kalman filter in overcoming the signal noise and gyro drift in the attitude sensors and simulate the PID controller which controlling the quadrotor dynamics through damping the vehicle oscillation. In this research, simulation of Kalman Filter in filtering the noise from the inertial moment unit (IMU) and PID controller in damping on unstable oscillation has been conducted to observe the performance of the quadrotor.

Abstract: Aortic cannula is one of major factors leading to adverse events such as thrombosis and atherosclerosis development during open heart surgery. This is due to oxygenated blood outflow with high velocity jet from heart lung machine when exiting the cannula tip into ascending aorta. It was discovered, and validated by several researchers that blood flow out of the left ventricle into the aorta is spiral in nature. In this study, a novel design in which internal profile of the cannula was made to induce spiral flow were tested by way of numerical simulation, and compared against existing commercial cannula. Three designs were tested, which differed in number of groove employed. Among the cannula model designs, cannula design with 4 grooves yielded the lowest value of maximum wall shear stress at testing tube with 3.778 Pa and highest value of area weighted helicity density at 40 mm from cannula tips with 11.829 m/s². Overall, spiral cannula models were showed highly potential in inducing spiral flow, and also the effect on blood hemolysis is acceptable.

Abstract: Buses are one of the important public transportation in Malaysia and commonly important for the student in any university. Thus, the study about Whole-Body Vibration (WBV) exposure induces to Low Back Pain (LBP) among the Universiti Tun Hussein Onn Malaysia (UTHM) was done. The objective was determine whether the bus drivers in UTHM would exceed the exposure action and limit values from the ISO 2631-1 (1997) during the working hours. Data collected according to different type of buses and evaluated the vibration significant different between buses based on the subjective correlation due to WBV questionnaire analysis. Analyze the prevalence of LBP based on the measurement and the questionnaire analysis. The study based on the international standard ISO 2631-1 (1997) which is related to the root-men-square (r.m.s) and Vibration Dose Value (VDV) parameter. The study covered among the bus drivers in UTHM. The measurement tools involved in the study is Larson Davis Vibration Meter (HVM 100) with Tri-axial Seat Pad Accelerometer to record data collection. The BLAZE software analyze the vibration exposure exceed the total vibration exposure according to 8 hours day A(8) value of 1.15 m/s² and VDV value of 21.0 m/s^1.75. The IBM Statistical Package for Social Science (SPSS) was used to do statistical analysis and testing involved was correlation, regression and ANOVA. Result obtained shows the A(8) and VDV was under EAV with highest value of 0.520 m/s² and12.65 m/s^1.75. The highest contribution factors by the duration to complete single trip per day (α=0.500).The further re-assess of working schedule need to be done in order to control the exposure level toward drivers. The assessment should be done for every two years.

Abstract: Since the earliest days of ground road transportations and constructions in urban areas, there have been complaints of vibration in building caused by this external source of vibration, known as ground borne vibration. Vibration when it exceeds the recommended threshold could affect the structure of the building and any sensitive equipment housed inside the building, as well as causing discomfort and annoyance to the occupants of the building. The objectives of the study are to determine the level of vibration on each floor of a multi storey building due to ground borne vibration from road traffic, second to numerically investigate the structural response on the multi storey building from vehicles, and lastly to assess the vibration response obtained from both vehicles with the vibration criteria guideline. The selected building for this study is Registrar Office building located in Universiti Tun Hussein Onn Malaysia (UTHM). The scope of study is focused on the effect of ground borne vibration from vehicles on multi storey building and analyzing the data using MATLAB and ANSYSv14. The real inputs of vibration from vehicles were measured and obtained using Laser Doppler Vibrometer (LDV). The vibration level from vehicles and footfalls on the multi storey office building can be determined using Vibration Criteria (VC) guidelines by Gordon. Finally, from the study, the vibration level achieved for this Registrar Office building is above the ISO level which is exceeds the acceptable vibration limit for office building.

Abstract: In this paper the Takagi-Sugeno type fuzzy logic was utilized for the purpose of control of electromagnetically levitated steel ball system. The system is the basis for important systems such as, the modern train which floats along the rails, aerospace shuttles, magnetic bearings and high precision systems. Such systems apart from being nonlinear they are also not stable. Results were obtained using the SIMULINK/MATLAB software and the control system developed for the electromagnetically levitated steel ball system was able to stabilize it with good response.

Abstract: Application of Fast Fourier Transform (FFT) in machinery faults detection is known to be only effective if fault is of repetitive in nature and considering severe. While minor and transient faults are usually remain undetected based on vibration spectrum analysis. Wavelet analysis is relatively new technique which is still suffered from inadequately in its time-frequency resolution. In this paper, ahmedrabak_time wavelet is proposed based on the wavelet reassignment technique for Morlet mother wavelet. The proposed wavelet analysis is compared to the conventional wavelet analysis for machinery faults detection based on simulated signal. The results showed that the proposed wavelet has a better resolution than conventional wavelet analysis which could clearly indicate the presence and the location of the fault.

Abstract: Blade fault is one of the most causes of failure in turbo machinery. This paper discussed the time frequency analysis for blade rubbing detection from casing vibration signal. Feasibility of Short Time Fourier Transform (STFT), Wigner-Ville distribution (WVD) and Choi-Williams distribution (CWD) were examined for blade rub detection in a multi stage blade system through an experimental data. Analysis results of the experimental data showed that these time frequency analysis methods have some inevitable deficiencies in segregating the blade passing frequency (BPF) components of the three rotor stage signals. However, CWD demonstrated a better time-frequency resolution in analyzing the multi stage rotor system signal.

Abstract: Landfill site selection is a complex task that needs to be done by decision maker. There are many criteria that need to be considered before choosing the landfill. This includes economic, social, geological and environmental criteria. AHP is a technique for analyzing and supporting decisions in which multiple and competing objectives are involved and multiple alternatives are available. By using Analytical Hierarchical Process (AHP), the process of landfill site selection had become easier. In this method, the problem need to be divided into hierarchy before the pair wise comparison and made it prioritize accordingly. Then, the judgment will be synthesized and finally, the evaluation and consistency of judgment were checked. As a result, lists of criterion were arranged according to its priority, which is more dominant to economic aspect and less dominant to social aspect. This is on account of social matters can be solved alternatively by different systems. This landfill site selection process involved lots of spatial data and strenuous in handling it. Thus, by using GIS, it can give significant helps to solve this issue because of its potential in handling large volume of spatial data that needs to be evaluates and processed. This particular research used Johor Bahru, Johor for case study area.