Structural Health Monitoring (SHM) system can be considered as an Internet-of-Things (IoT) system implemented to engineering structure to provide real-time information on the integrity of the structure. In doing so, t...
Structural Health Monitoring (SHM) system can be considered as an Internet-of-Things (IoT) system implemented to engineering structure to provide real-time information on the integrity of the structure. In doing so, the system acquires data from various sensors distributed across the structure and infers damage sensitive quantities. In the research, we proposed a damage index derived from the governing dynamics of the structure in the frequency domain. The proposal was empirically verified by applying the index to analyze the case of a cracked cantilever beam subjected to a harmonic load. The value of the damage index was computed at some points surrounding the crack to understand the effect of the distance of the monitoring point to the crack to the index sensitivity. The results suggest that the index is sensitive to the crack particularly when the observation point is near the crack.
Cyber-physical systems (CPS) such as autonomous vehicles rely on both on-board sensors and external communications to estimate their state. Unfortunately, these communications render the system vulnerable to cyber-att...
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Analysis of sediments from rivers, lakes, reservoirs, wetlands and other constructed surface water impoundments is an important tool to characterize the function and health of these systems, but is generally carried o...
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Sb is chosen as an additive to bind lanthanides in U-10Zr metallic fuel and the effectiveness was demonstrated in as-cast sample. Upon annealing, no evidence of free Sb was observed in both alloys. This is important a...
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In this work, a 3-D numerical method is employed to predict the noise propagation within the University of the District of Columbia (UDC). UDC is located within an urban environment in Washington, DC. Sound pressure l...
In this work, a 3-D numerical method is employed to predict the noise propagation within the University of the District of Columbia (UDC). UDC is located within an urban environment in Washington, DC. Sound pressure level measurements of various noise sources including traffic noise are obtained. Of particular interest is the method’s ability to accurately simulate the urban space. Accuracy is evaluated comparatively between simulated and measured results of acoustic parameters in the mid-to-high-frequency regimes. Specifically, reverberation time, energy decay time, and sound pressure level. The results and limitations of the particle-tracing method for predicting sound propagation in urban environments are discussed.
Although Structure-from-Motion (SfM) as a maturing technique has been widely used in many applications, state-of-the-art SfM algorithms are still not robust enough in certain situations. For example, images for inspec...
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To monitor safely managed drinking water services, an increasing number of countries have integrated water quality testing for Escherichia coli into nationally-representative household surveys such as the Multiple Ind...
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Enabling robots to walk and run on yielding terrain is increasingly vital to endeavors ranging from disaster response to extraterrestrial exploration. While dynamic legged locomotion on rigid ground is challenging eno...
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The advanced machining of components used in miniature unmanned aircraft vehicles is the focus of this study. The finite element method (FEM) is used to predict forces and temperatures using cutting tool inserts with ...
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The advanced machining of components used in miniature unmanned aircraft vehicles is the focus of this study. The finite element method (FEM) is used to predict forces and temperatures using cutting tool inserts with a thin nanostructured film of high integrity. Similarity models are used to validate the finite element results and to understand the influence of micromachining parameters on cutting temperatures generated when machining Al 380-0 alloy. The predicted results are compared to experimental forces and temperatures using a three-dimensional piezoelectric function dynamometer and a short-range infra-red wavelength thermal camera. Nanostructured thin layer coatings lower machining forces and temperatures, which are validated through FEM predictions and experimental observations. The experimental results suggest that increasing the cutting tool’s rake angle at higher depths of cut will reduce cutting temperatures, which are predicted using the similarity models for micromachining.
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