Vibration Analysis Of The Chenderoh Dam Structure Due To The Effects Of Water Spilling And Surging

Dam structure has to be inspected regularly in order to monitor its reliability due to the effect of flow-induced vibration. Vibration induced by the fluid (water) on the dam structure can lead to the catastrophic failure if the natural frequencies coincide with the frequencies of the water flow. In this research, the effects of water spilling and surging to the Malaysian Chenderoh Dam in terms of vibration are studied. For this purpose, only spillway and intake sections of the Chenderoh Dam are taken into consideration. Modal and Harmonic Analyses are carried out using ANSYS software version 18.2 (ANSYS 18.2) to determine the dynamic characteristics of the dam structure. Next, fluid-structure interaction (FSI) simulation study is conducted and the Operational Deflection Shapes (ODS) from the effect of flow-induced vibration are compared with the natural frequencies and mode shapes of the dam structure. From the results, the natural frequencies obtained for spillway and intake sections are 5.09 Hz and 2.76 Hz respectively. The FSI analysis produced the operating frequency of 4.71 Hz for Case 1 and 7.45 Hz for Case 2-4 of spillway section. This indicates that there is no resonance phenomenon during the operating condition of the spillway. However, resonance phenomenon may occurred for the Case 3 of intake section where the forcing frequency from the FSI analysis (2.35 Hz) coincides with the natural frequency of the intake section. This means that the intake is considered unsafe for this operational condition. Thus, a proper closing procedure for both gates should be conducted to avoid any failure to the structure

Design Of Master Mask Film, Fabrication Of PDMS Mold And Fabricate Uv Led Curing Unit To Test Imprint Capability Of Roll-To-Plate Nanoimprint Lithography System

Current optical lithography method still cannot cope with the increasing demands from the industry especially electronics and biomedical industry. Not just it is low throughput; it is also difficult to conduct, not to mention the end product of this method is not as accurately as anticipated. Due to these limitations, lots of other alternatives are being developed and one of it is nanoimprint lithography (NIL). NIL is a better alternative to the conventional lithography method as it is simpler, cheaper and has higher throughput. Roll to plate NIL is one of the many NIL techniques and it will be focused in this project. The main objectives of this study is to modify the roll to plate NIL machine which is still under development so that it can be a complete machine capable of both large area mold making and roll to plate NIL process. This project can be divided into two parts; modifications of the roll to plate NIL machine and NIL process. Modifications include installation of heating element, UV curing station, doctor blade mechanism, seamless mold station, motors and other supporting components. Because the roll to plate NIL machine is still not fully complete, NIL process was done using plate to plate NIL machine to test its concept. Although the machine used is different, the concept of NIL is still the same. First of all, the designed patterns are directly transferred from master mask film to microscope glass, aided by UV rays. Then, the patterns are replicated to PDMS mold before being imprinted to silicon substrate using plate to plate NIL machine. At first, the designed patterns were successfully imprinted on the silicon substrate but it was less accurate as some patterns cannot be seen. In the second experiment, the new structures has been successfully imprinted with better results along with its dimensions

An Investigation of the Reliability of Different Types of Sensors in the Real-Time Vibration-Based Anomaly Inspection in Drone

Early drone anomaly inspection is vital to ensure the drone’s safety and effectiveness. This process is often overlooked, especially by amateur drone pilots; however, some faulty conditions are difficult to notice by the naked eye or discover, even though the drone inspection process has been conducted; therefore, a real-time early drone inspection approach based on vibration data is proposed in this study. Firstly, the reliability of several microelectromechanical systems (MEMS) sensors, namely the ADXL335 accelerometer, ADXL 345 accelerometer, ADXL377 accelerometer, and SW420 vibration sensor in detecting faulty conditions, were tested and compared. The experimental results demonstrated that the vibration parameter measured using ADXL335 and ADXL345 accelerometers are the best choice as most of the faulty conditions can be detected, in contrast to other MEMS sensors. The output produced from the anomaly inspection algorithm is then converted to the “Healthy” or “Faulty” state, which is displayed in a mobile application for easy monitoring

Prediction of the Flow-Induced Vibration Response of the Chenderoh Dam Left Bank Section

Flow-induced vibration is a common phenomenon that happened in any of dam structures during the operational condition. This includes the effect of water spilling from the upstream to the downstream of the dam due to high water volume at the upstream side. the release of water from the dam can be beneficial in generating the electricity source to the surrounding areas. However, in some cases, the spill of water can induced the significant vibration effects to the dam structure. In this study, the prediction of the flow-induced vibration response at the left bank section of the real scale Malaysian Chenderoh Dam model is simulated using the ANSYS software. the input force disturbances from the flow of the water at the left bank section during the normal water spilling condition is investigated. the results of frequency domain response and operational defection shapes (ODS) from the effect of flow-induced vibration are compared with the natural frequencies and mode shapes of the dam. From the results, the transient vibration responses due to the flow of water happened at the frequency of 13.3 Hz while the natural frequency of the left bank section occurred at 52.3 Hz, which indicates that there is no resonance phenomenon for the normal case of water spilling at the left bank section of the dam structure. This result is useful for the dam operation section in order to avoid any disaster of the dam structure

Structural Dynamic Analysis of the Chenderoh Dam Sector Gate Section

The dynamic characteristics such as natural frequencies, mode shapes and frequency response function (FRF) are the important characteristics to be investigated to access the level of durability of any dam structures. These characteristics are important since it will be the reference information for any operational methods to be used for the dam structures. In this study, one of the real dam (i.e., Chenderoh Dam) that available in Malaysia is taken into consideration, where the dynamic analysis of the sector gate section of the dam structure is investigated. the real scale of the sector gate section is measured on site and modelled into the CAD software with the consideration of real build-in materials. Then, the finite element (FE) model is constructed in ANSYS software with the required boundary condition and meshing sensitivity analysis. From the result of modal analysis, 30 natural frequencies are determined in the range of 0.5904 Hz to 8.471 Hz together with the mode shapes but only the most significant natural frequencies will be shown in this paper. In addition, all three axes of the FRF graphs show an agreement for the highest natural frequency value at 7.95 Hz, where the maximum deflection occurred in x axis direction with 2.03 × 10-7 m