Browsing by Author "Rahman, Fazlar"

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    Numerical analysis of contact behavior of a sliding microwire
    (Department of Mechanical Engineering (ME), BUET., 2023-09-30) Rahman, Fazlar; Akanda, Dr. Md. Abdus Salam
    MEMS devices employ the mechanical behavior of microstructures for sensing, controlling, and actuating. Their function, reliability, and fatigue life greatly depend on the microstructure’s mechanical behavior. Microstructures have an infinitesimal stiffness and high surface-to-volume ratio. Consequently, its behavior is influenced by surface forces and forces arising from the external fields/sources. The undesirable/excessive forces hinder MEMS function and act as a disturbance. Therefore, their assessment and control are crucial for the design of MEMS devices. Microstructures experience sliding motion in MEMS devices, where friction force is dominant. In this study, the contact behavior and friction force of a microwire are evaluated numerically for the push-pull sliding motion against two opposite microprobes. The microwire is manipulated against microprobes by a Double Beam Cantilever (DBC), where one end of the microwire is attached at the tip of the DBC and the other end is supported between microprobes by frictional contact. The microwire's friction force and contact behavior are evaluated numerically by the FEA tool ANSYS Workbench. The results are validated by comparing with the experimental results available in the literature. The effects of variation of the contact pressure, size, and boundary conditions of the microwire on the friction force are also investigated. The vibrational characteristics of DBC are evaluated numerically and compared with Single Beam Cantilever (SBC) for MEMS manipulation. Besides, the electrostatic and adhesive forces between the microwire and microprobe are assessed for a single contact, where the available experimental deformations of the microwire under electrostatic and adhesive force are used as boundary conditions of the numerical analysis. The numerical analysis is performed in the absence of all disturbance forces other than friction force. Therefore, the difference between the available experimental and numerical results reveals the sum of all surface and external disturbance forces in the microwire. The surface forces, such as adhesive, electrostatic, etc., and the sum of disturbance forces arising from the external sources/fields are predicted by comparing numerical results with the experimental results. This study's results reveal that the friction force in sliding microstructures can be controlled by suitable size and boundary conditions besides surface asperity. This study will help to evaluate friction force and contact behavior in other microstructures, such as microbars, microplates, etc., for sliding motion, and to select the appropriate type and length of the cantilever for MEMS application. Besides, it will aid in achieving MEMS devices' reliability and fatigue life by assessing surface and external disturbance forces in microstructures.
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    The Impact of Modern Research and Innovation on Society and Individuals
    (Research and Development Wing, MIST, 2025-06) Rahman, Fazlar; Rabbi, Fazle; Bhuiyan, Md. Shahnewaz; Harun-or-Rashid, Mohammad
    Life quality and socio-economic conditions have improved dramatically over the last century due to the rapid advancement and innovation of modern technologies, which have evolved from the fruitful research of scientists. It will continue to grow throughout the twenty-first century and beyond and reach every corner of the globe without ambiguities. Scientists research and innovate ideas, technology, and tools for enhancing life quality, productivity,economy, and environment. However, inappropriate implementation, strategy, and design could drive society and individuals backwards. Recently, humans have encountered severe and periodic natural catastrophes, such as intense hot and cold climates, deluges, tsunamis, typhoons, landslides, droughts, wildfires, pandemics, etc., as well as nation-and society-driven riots, wars, espionage, and social phobia, where modern tools and innovations employed. It severely affects the mental health and socio-economic conditions of individuals and society due to the damage to infrastructure, shelter, agricultural land, deaths of humans, animals, and livestock, and environmental pollution. Besides, detrimental events are caused by environmental pollution and global warming and are triggered by human activities and abusing of modern innovations and science. This study qualitatively explores the most influential impacts of contemporary research and innovation in different fields on society and individuals by investigating the recent relevant research and events. It is revealed that modern innovations and technology have severe detrimental impacts on society and individuals if they are abused and executed recklessly. This study will aid in reducing and understanding the harmful effects of research and innovation on society, ultimately enhancing social health and progress.