Force Distribution Along Tree Branch – Static Analysis

Abstract

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.