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On the Computational Efficiency of the Hybrid Approach in Numerical Simulation of Rockall Flexible Chain-Link Mesh

  • S. TahmasbiEmail author
  • A. Giacomini
  • C. Wendeler
  • O. Buzzi
Original Paper
  • 105 Downloads

Abstract

Rigorous design of flexible rockfall protection systems requires an adequate understanding of the system performance. In recent decades, finite element simulations have complemented experimental testing for economical and practical reasons. However, complex modelling techniques are required to capture the dynamic response of such systems, which leads to considerable computational costs. This paper presents a new approach called “hybrid method” to improve the computational efficiency of FE models with minimum effects on the results accuracy. The method is based on the idea to model the exact architecture of the wire net in the vicinity of impact (zone undergoing plastic deformation and failure) and to model the mesh with less computationally expensive elements far from the impact (zones undergoing elastic deformation). To this aim, a three-dimensional model of chain-link mesh was developed using commercial finite element code ABAQUS. The real architecture of the wires is modelled and discretised using three-dimensional beam elements. Homogenised shell surfaces are used to model the chain-link away from the impact zone. The model was calibrated and validated against published experimental data. The results prove that the proposed hybrid method leads to considerable reduction in computational costs of the finite element analysis while producing accurate results.

Keywords

Rockfall barrier Chain-link wire net Finite element analysis Hybrid method Shell elements 

List of Symbols

a

The smaller diagonal of the chain-link rhomboid

b

The larger diagonal of the chain-link rhomboid

θ

The smaller angle of the chain-link rhomboid

ω

The aperture size of the chain-link rhomboid

d

The diameter of the chain-link wires

\(\eta\)

Stress triaxiality

p

Hydrostatic pressure

q

Mises equivalent stress

\(\dot{\bar{\varepsilon }}^{\text{pl}}\)

Equivalent plastic strain rate

\(\dot{\varepsilon }^{\text{pl}}\)

Plastic strain rate

\(D\)

Damage factor

\(\alpha_{\text{damage}}\)

Exponent of the damage evolution law formulation

\(\bar{u}^{\text{pl}}\)

Equivalent plastic displacement

\(\bar{u}^{\text{pl}}_{\text{f}}\)

Equivalent plastic displacement at failure

L

Characteristic length of the element

Vimp

Block impact velocity

Vini

Block initial velocity

g

Gravity acceleration

h

Vertical distance between the block and the mesh at the end of gravity step

h1

Initial distance (before gravity step) between the block and the mesh

h2

Initial sag of the mesh at the end of gravity step

ε

Strain

E

Young’s modulus

ν

Poisson ratio

G

Shear modulus

σ

Stress

ρ

Density

\(A_{\text{sh}}\)

Area of the shell surface

M

Mass of the mesh replaced with shell surface

\(t_{\text{sh}}\)

Thickness of the shell surface

Notes

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Copyright information

© Springer-Verlag GmbH Austria, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Priority Research Centre for Geotechnical Science in EngineeringUniversity of NewcastleCallaghanAustralia
  2. 2.Geobrugg AG-Geohazard SolutionsRomanshornSwitzerland

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