The elasto-mechanical behaviour of Douglas fir, its sensitivity to tree-specific properties, wind and snow loads, and implications for stability - a simulation study

Gaffrey, D.; Kniemeyer, O.

doi:10.17221/11856-jfs

Cited by 17 publications

(10 citation statements)

References 42 publications

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“…Trees are exposed to different kinds of mechanical loading as wind, snow and ice [1,2,3], where the wind is considered to be the major one [4]. The evaluation of tree response to wind load is a key aspect of tree stability assessment.…”

Section: Introductionmentioning

confidence: 99%

Force Distribution Along Tree Branch – Static Analysis

Vojáčková¹,

Tippner²,

Dlouhá³

2021

14th WCCM-ECCOMAS Congress

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The standard approach of tree stability assessment assumes that wind force is applied in a unique point (centre of gravity). Such a description of the loading brings a significant simplification of the reality, where the tree stem is submitted to multiple forces distributed from higher-order branches to lower order one. The aim of this study is to describe the influence of the simplification by comparison of branch response (deflection curve, bending moment) in the case of single-and the multi-point loading. Four beam-like models were built in ANSYS APDL according to geometry (tapered beams with realistic elliptical cross-sections) and material properties (shear included) of real tested branches. The models were experimentally validated in the case of single-point loading and consequently used for simulations of various loading scenarios. The distribution of force along the branches, by weighted division of total wind force according to different properties of branches, was applied. The branch response differs between single-and multi-point loading in the case of deflection curve, whereas the bending moment at branch anchorage is comparable.

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Section: Introductionmentioning

confidence: 99%

Force Distribution Along Tree Branch – Static Analysis

Vojáčková¹,

Tippner²,

Dlouhá³

2021

14th WCCM-ECCOMAS Congress

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“…For the uncertainty about the appropriate exponent and reliability of the conventional form, Cullen [19] reported on modeling of aerodynamic drag equation forms and concluded that conventional form could be appropriate for trees. Gaffrey et al [20,21] developed a complete 3D model to simulate the elastic mechanical behavior of trees under wind and gravity. The stress and strain distribution at the surface of stem could be estimated using this model.…”

Section: Introduction mentioning

confidence: 99%

Physics-based algorithm to simulate tree dynamics under wind load

Yang

Ding

et al. 2020

International Journal of Agricultural and Biological Engineering

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Rapid development in the different computer science fields during the recent decades has facilitated the creation of new applications in the area of dynamic simulation of plant development. Among these new applications, simulation of trees swaying in the wind is of great importance, as those computer graphics related areas, e.g., computer games, tree cultivation and forest management simulations, help a lot in revealing the mechanisms of tree dynamics under wind load. However, it is a big challenge to balance the effect of visualization in real time and calculation efficiency for any simulation algorithm. A physics-based algorithm to simulate tree dynamics under wind load was proposed in this study. A mechanistic model simulating the bending of a cantilever beam was used within the algorithm to simulate deformation of stems, and the algorithm was integrated with a landscape model in which different types of trees were constructed with an L-system-based formalism. Simulation results show that realistic dynamic effects can be achieved with reasonably high computational efficiency.

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“…Crown size and shape has been generally found to play a significant role in how trees resist wind, snow, and ice loads (Niklas & Spatz 2000, Gaffrey & Kniemeyer, 2002. Wind induced stress varies along the length of the stem and is partly influenced by the crown shape and size, as well as, stem taper (Niklas & Spatz 2000).…”

Section: Crown and Branchesmentioning

confidence: 99%

“…Snow and ice also cause loading on trees, though these types of loading are generally regarded as static (James et al 2014, Dahle et al 2017. For examples of studies examining snow and ice loads, see: Peltola et al 1999, Gaffrey & Kniemeyer 2002, and Lulely & Bond 2006. In addition to external forces, decay can deteriorate wood strength, particularly decreasing the moment capacity of the stem or branch, thus heightening the likelihood of failure (Ciftci et al 2013).…”

Section: Introductionmentioning

confidence: 99%

Assessment of Unmanned Aerial Systems and lidar for the Utility Vegetation Management of Electrical Distribution Rights-of-Ways

Walker¹

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Assessment of Unmanned Aerial Systems and lidar for the Utility Vegetation Management of Electrical Distribution Rights-of-WaysMatthew R. Walker Utility Vegetation Management (UVM) is often the largest maintenance expense for many utilities. However, with advances in Unmanned Aerial Systems (UAS; or more commonly, "drones") and lidar technologies, vegetation managers may be able to more rapidly and accurately identify vegetation threats to critical infrastructures. The goal of this study was to assess the utility of Geodetics' UAS-lidar system for vegetation threat assessment for 1.6 km of a distribution electric circuit. We investigated factors which contribute to accurate tree crown detection and segmentation of trees from within an UAS-lidar derived point cloud, and the factors which contribute to accurate tree risk assessment. The study adapted the International Society of Arboriculture's (ISA) tree risk assessment methodology to the application of remotely sensed tree inventory. We utilized the lidar detected and segmented tree crowns for tree risk analysis based upon each tree's height, elevation, and location in relation to the electrical infrastructure. The individual tree detection and segmentation results show that our canopy type parameter and the routine used for field-and lidar-derived tree matching to have the largest effect on the classification agreement of field and lidar derived datasets. The Threat Detection classification also demonstrated a significant effect due to our canopy modeling parameter, where single canopy models possessed higher average Kappa agreement statistic and divided canopy models detected a larger number of threats on average. Ultimately, our best model was capable of the correct detection, segmentation, matching, and classification of half of the field trees which were determined to be vegetation threats.

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The elasto-mechanical behaviour of Douglas fir, its sensitivity to tree-specific properties, wind and snow loads, and implications for stability - a simulation study

Cited by 17 publications

References 42 publications

Force Distribution Along Tree Branch – Static Analysis

Force Distribution Along Tree Branch – Static Analysis

Physics-based algorithm to simulate tree dynamics under wind load

Assessment of Unmanned Aerial Systems and lidar for the Utility Vegetation Management of Electrical Distribution Rights-of-Ways

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