Experimental and numerical dynamic analysis of a live tree stem impacted by a Charpy pendulum

INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES

卷:50

Article

Bertrand, D.¹  Bourrier, F.²  Olmedo, I.^1,2  Brun, M.¹  Berger, F.²  Limam, A.¹ 

[1] INSA Lyon, LGCIE, F-69621 Villeurbanne, France

[2] Irstea Grenoble, EMGR Ecosyst Montagnards, F-38402 St Martin Dheres, France

关键词: Rockfalls;    Natural hazards;    Live tree stem;    Impact dynamics;    FEM non linear computations;    Experimental impact tests;    Calibration and validation;   

DOI  :  10.1016/j.ijsolstr.2013.01.037

来源: Elsevier

【 摘 要 】

In recent years, the forest has been used as a protective structure to reduce rockfall propagation. When a rock propagates down a forested slope, it hits trees and these interactions modify its trajectory. This paper focuses on the dynamic behavior of small-diameter live trees impacted by a rock To better understand the protective effect of forests against rockfalls, a finite element (FE) model of a live stem subjected to a local dynamic loading is proposed. Large displacements and material nonlinearities are taken into account. The numerical simulations are calibrated based on laboratory tests (free oscillation tests and impact tests). The displacement field measured by a high-speed camera is correctly reproduced by the FE model for both kinds of tests. For impact tests, the analysis of the impactor-stem interaction identified three main regimes of the stem's response (quasi-static/intermediate/impulsive). These depend on the impactor's and stem's mechanical and geometrical features (relative mass and stiffness). Finally, we attempt to predict the regime response of the stem as a function of its diameter and the impactor mass. (C) 2013 Elsevier Ltd. All rights reserved.

【 授权许可】

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