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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 22 for “"Ambient vibrations"”.
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Structural damage detection using ambient vibrations
… objective of this research is to use structure ambient random vibration response to detect damage level and location. The use of ambient vibration is advantageous because excitation is caused by service conditions such as normal vehicle traffic on a highway bridge, train passage on a railroad …
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Effect of potential shape and excitation spectrum on power harvested from ambient vibration
… developments in energy harvesting from ambient vibrations in small-scale sensing. The ultimate goal is to replace batteries in these sensors. Linear systems have a narrow bandwidth, but ambient vibrations occur over a potentially broad range of frequencies. Nonlinear systems-in …
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Design of test bench apparatus for piezoelectric energy harvesters
… that are able to harvest energy from their ambient vibrations using piezoelectric material property, and many different designs are being researched by the Micro & Nano Systems Laboratory. In order to analyze the different designs, it is crucial to have a flexible test bench, and the test …
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A vibration-based bridge scour monitoring technique
… with pre-existing scour, which was monitored for ambient vibrations throughout a repair process involving controlled scour backfilling, i.e., “scour in reverse”. The effect of this scour backfilling was captured by measuring changes in two of these parameters, mode shape and spectral density, …
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The design of low-frequency, low-g piezoelectric micro energy harvesters
… harvester will generate electric power from ambient vibrations in the frequency range of 200~30OHz at excitation amplitude of 0.5g. Our previous energy harvester successfully resolved the gain-bandwidth dilemma and increased the bandwidth two orders of magnitude. By utilizing a doubly clamed …
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Low-frequency, low-amplitude MEMS vibration energy harvesting
… low-amplitude and unpredictable nature of ambient vibrations. Bi-stable nonlinear oscillator based energy harvesters are developed for lowering the operating frequency while widening the bandwidth, and are realized at MEMS scale for the first time. This design concept does not rely on the …
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Smart Systems Based on Electroactive Polymers
… and of a device able to harvest energy from ambient vibrations. This work has allowed to assert that, although the technology used is still room for improvement, this idea is feasible.
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Design of Structural Stand for High-Precision Optics Microscopy
… the microscope to the concrete ground. Due to ambient vibrations experienced in the system, the microscope is only able to reliably reach a 10-µm level of precision.</p> <p>As NIF’s technology advances, there is a need to both increase optic measurement throughput and to measure damage sites at …
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Energy Harvesting Applications of Ionic Polymers
… to supply renewable power harvested from ambient vibrations to a wireless sensor. Ionic polymers were investigated as mechanical to electrical energy transducers. An ionic polymer device was designed to harvest energy from vibrations and supply power for a wireless structural health …
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Characterization of structural properties and dynamic behavior using distributed accelerometer networks and numerical modeling
… Survey, the response accelerations from ambient vibrations, seismic loading, and firework excitations were collected. Spectral analysis methods were applied to the collected data to identify the frequencies and general mode shapes of eight normal modes of the structure. These frequencies …
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Tiny Piezoelectric Energy-Harvesting CMOS Charger
… transducer can draw kinect energy from ambient vibrations to constantly replenish the batteries. Tiny piezoelectric transducers, however, only draw a small portion of the energy from vibration. Moreover, the charger is lossy, and imposes limits on the operation. The objective of this …
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Energy harvesting of random wide-band vibrations with applications to an electro-magnetic rotational energy harvester
… vibration energy harvesting is the scavenging of ambient vibration by transduction of mechanical kinetic energy into electrical energy. Many mechanical or electro-mechanical systems produce mechanical vibrations. The kinetic energy associated with these mechanical vibrations represents a potential …
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Smart Nanocoated Structure for Energy Harvesting at Low Frequency Vibration
… materials can be used as a means of transforming ambient vibrations into electrical energy that can be stored and used to power other devices. With the recent surge of micro scale devices, piezoelectric power generation can provide a convenient alternative to traditional power sources. In this …
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Micro-Scale and Nonlinear Vibrational Energy Harvesting
… to resonant at the dominant frequency of the ambient vibration. The fundamental natural frequency of a beam increases as its length decreases, so that at the MEMS scale the resonance condition occurs orders of magnitude higher than ambient vibration frequencies rendering the harvester …
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Broadband Piezoelectric Energy Harvesting and Vibration Suppression Using Nonlinear Mechanisms
Harvesting ambient vibration energy provides a promising solution to implement self-powered microwatts to milliwatts low-power electronic devices, as an alternative to batteries. Due to the high power density and simple construction, piezoelectric transducers have attracted the most attention in …
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Optimisation and frequency tuning concepts for a vibration energy harvester
… as energy scavenging) is the process whereby ambient energy is captured and stored. The ambient energy here refers to energy that is pre-existing in nature, and is self-regenerating and has extended life time from a battery. After reviewing many possible energy scavenging methods, the …
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High-Resolution, High-Frequency Modal Analysis for Instrumented Buildings
… structures has been limited to low frequency ambient excitation and sparse sensor networks, due to practical limitations. Two key components for high-frequency modal analysis have yet to be studied: 1) Sufficient excitation at high frequencies and 2) high-resolution (high sensor density) …
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Simultaneous Energy Harvesting and Vibration Control via Piezoelectric Materials
… wing itself is able to harvest energy from the ambient vibrations along with available sunlight during normal flight. If the wing experiences any strong wind gust, it will sense the increased vibration levels and provide vibration control to maintain its stability. This work holds promise for …
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MEMS Technologies for Energy Harvesting and Sensing
… and also extends their use to remote and extreme ambient applications. Unlike inductive harvesting, piezoelectric and magnetoelectric devices lend easily to MEMS scaling. The processing of such Piezo-MEMS devices often requires special fabrication, characterization and testing techniques. Our …
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Dynamic Testing of an Elevated Water Tank
… water tank in its current environment through ambient vibration testing. </p>
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