Contact force calculating and force chain recognizing method for particles in three-dimensional particle system

Abstract

The invention belongs to the technical field of particle system force chain recognition and relates to a contact force calculating and force chain recognizing method for particles in a three-dimensional particle system. The method comprises the steps of putting balls into a rigid container to form the three-dimensional particle system, utilizing a loading pressure head to pressurize the three-dimensional particle system, collecting an original sequence image and a target sequence image through an XCT scanner, utilizing a digital body related method to analyze the obtained original sequence image and the target sequence image to obtain stress of all points, then performing image edge detection on a target image, recognizing a particle centroid, reading coordinates of the particle centroid and position coordinates of contact points of all particles, establishing an equation set according to balance conditions of all the particles and solving the equation set to obtain magnitude and direction of contact force fi of all the contact point positions on each particle. The method has a simple principle, is convenient and flexible to use and has strong practicability, application environment friendliness and wide market prospect; in addition, required equipment is simple and easy to obtain, and measurement results are accurate.

Description

Technical field: [0001] The invention belongs to the technical field of particle system force chain identification, and relates to a method for calculating the contact force between particles in a three-dimensional particle system and identifying a force chain. The XCT scanning particle system is used to perform digital volume correlation operations on scanned images to obtain three-dimensional particles. The displacement and strain are calculated to obtain the contact force between particles. Background technique: [0002] As a complex system formed by the interaction of a large number of discrete particles, granular matter is ubiquitous in nature, daily life, and production. Its mechanical properties are between solids and liquids, and are far more complex than ordinary solids and liquids. Solid mechanics, fluid mechanics theory or condensed matter physics knowledge to explain. [0003] Under the action of gravity or external load, a network structure with collimation cha...

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Problems solved by technology

However, both the photoelastic experiment and the DIC method at this stage have deficiencies. The photoelastic experiment carried out at the present stage is a model experiment, and the experimental results can only provide reference for the force model and constitutive relationship of real sand particles, while real sand, etc. Particles have the characteristics of different shapes, textured surfaces and opaque materials, so it is impossible to use the photoelastic method for actual measurement, so the photoelastic experiment is not enough for most practical projects to be directly adopted, and has certain limitations; although the application of the DIC method is for particle systems The mechanical property test provides a new opportunity, but the published work is only the calculation of the contact force of the two-dimensional particle system and the extraction and identification of the force chain, and the calculation of the contact force between the particles in the three-dimensional particle system and the identification and extraction of the force chain have not yet been published. See relevant reports, there are certain limitations

At the same time, the identification and extraction of particle contact force and force chain combined with XCT scanning method has not been reported yet.

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