Automatic extraction method of force chain information and its application in the flow photoelastic experiment of granular matter--颗粒学报PARTICUOLOGY

Chen, Q., Long, E., Niu, W., Liu, J., Fan, W., & Li, H. (2023). Automatic extraction method of force chain information and its application in the flow photoelastic experiment of granular matter. Particuology, 83, 142-155. https://doi.org/10.1016/j.partic.2023.02.017

Automatic extraction method of force chain information and its application in the flow photoelastic experiment of granular matter

Qingfa Chen ^{a b}, Enlin Long ^a, Wenjing Niu ^b *, Jun Liu ^b, Wenyu Fan ^b, Hangyu Li ^b

a School of Civil Engineering and Architecture, Key Laboratory of Disaster Prevention and Structural Safety of Ministry of Education, Guangxi University, Nanning, 530004, China
b School of Resources, Environment and Materials, Guangxi University, Nanning, 530004, China

10.1016/j.partic.2023.02.017

Volume 83, December 2023, Pages 142-155

Received 1 December 2022, Revised 15 February 2023, Accepted 16 February 2023, Available online 9 March 2023, Version of Record 16 March 2023.

E-mail: niuwj@gxu.edu.cn

Highlights

• An automatic extraction method of force chain information in photoelastic experiment is proposed.

• The number, length, angle, strength type, and distribution of force chains are quantified.

• The strong force chains are mostly distributed in the left and right sides of the model.

• The weak force chains are mostly located in the middle of the model.

Abstract

The force chain is the core of the multi-scale analysis of granular matter. Accurately extracting the force chain information among particles is of great significance to the study of particle mechanics and geological hazards caused by particle flow. However, in the photoelastic experiment, the precise identification of the branching points of force chains has not been effectively realized. Therefore, this study proposes an automatic extraction method of force chain key information. First, based on the Hough transform and the Euclidean distance, a particle geometric information identification model is established and geometric information such as particle circle center coordinates, radius, contact point location, and contact angle is extracted. Then, a particle contact force information identification model is established following the color gradient mean square method. The model realizes the rapid calibration and extraction of a large number of particle media contact force information. Next, combined with the force chain composition criterion and its quasilinear feature, an automatic extraction method of force chain information is established, which solves the problem of the accurate identification of the force chain branch points. Finally, in the photoelastic experiment of ore drawing from a single drawpoint, the automatic extraction method of force chain information is verified. The results show that the macroscopic distribution of force chains during ore drawing from a single drawpoint is left–right symmetrical. Strong force chains are mostly located on the two sides of the model but in small numbers and they mainly develop vertically. Additionally, the ends are mostly in a combination of Y and inverted Y shapes, while the middle is mostly quasilinear. Weak force chains are abundant and mostly distributed in the middle of the model, and develop in different directions. The proposed extraction method accurately extracts the force chain network from the photoelastic experiment images and dynamically characterizes the force chains of granular matter, which has significant advantages in particle geometry information extraction, force chain branch point discrimination, force chain retrieval, and force chain distribution and its azimuthal characterization. The results provide a scientific basis for studying the macroscopic and microscopic mechanical parameters of granular matter.

Graphical abstract

Keywords

Granular matter; Photoelastic experiment; Digital image processing; Force chain extraction method

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