Examining the tree failure process from the biomechanics point of view using the innovative tree monitoring system

Chau, Wai Yi

doi:10.14711/thesis-991012880164803412

Cited by 1 publication

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“…The natural frequency f * obtained from a tree motion sensor installed on the tree (0.5 m above ground) are included in figure 9 a for comparison. The tree motion sensor was made by a microelectromechanical system accelerometer and a gyroscope (see Chau [50]). The modal frequencies f * identified by the LiDAR sensor and the tree motion sensor are similar, with relative differences of 3.5% and 2.7% for the first and the second modes, respectively.…”

Section: Resultsmentioning

confidence: 99%

Understanding the dynamic properties of trees using the motions constructed from multi-beam flash light detection and ranging measurements

Chau

Loong

Wang

et al. 2022

J. R. Soc. Interface.

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Measuring the three-dimensional motion of trees at every position remains challenging as it requires dynamic measurement technology with sufficient spatial and temporal resolution. Consequently, this study explores the use of a novel multi-beam flash light detection and ranging (LiDAR) sensor to tackle such a sensing barrier. A framework is proposed to record tree vibrations, to construct the motions of tree skeletons from the point-cloud frames recorded by the LiDAR sensor and to derive the dynamic properties of trees. The feasibility of the framework is justified through measurement on a Ficus microcarpa under pull-and-release tests. The relative differences for the first two modal frequencies between the LiDAR and linear variable differential transformer measurements in the displacement Fourier spectra are 0.1% and 2.5%, respectively. The framework is further adopted to study the dynamic response of different trees subjected to typhoons, including a Liquidambar formosana , three Araucaria heterophylla trees, a Sterculia lanceolata , a Celtis sinensis , a Tabebuia chrysantha and a Cinnamomum camphora . Results suggest that broadleaved trees might exhibit vibration in a wide frequency band, whereas the coniferous trees could follow a distinct dominant frequency.

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Section: Resultsmentioning

confidence: 99%