Contact force measurement test apparatus of granular material force chain structure, and application method thereof

Abstract

The invention discloses a contact force measurement test apparatus of a granular material force chain structure. The apparatus comprises a cylinder container, a fixation device, a power loading device, a thin film pressure transducer and a data calibration and acquisition system, wherein the cylinder container comprises a cylinder used for containing a granular material whose contact force needs to be measured, an upper piston used for covering an upper-end opening of the cylinder and a lower piston used for covering a bottom-end opening of the cylinder; the fixation device is used for fixing the cylinder; the power loading device can directly act on the upper piston and is used for providing a load needed during a test; the thin film pressure transducer is mainly composed of a sensor thin film portion; the sensor thin film portion is arranged between the sensing granular material and the lower piston; and the data calibration and acquisition system comprises a modulator, a calibration device, a USB gatherer and acquisition control software, and the thin film pressure transducer is connected with the data calibration and acquisition system. The test apparatus provided by the invention has higher precision and sensitivity and can more accurately carry out a contact force test and research of the granular material force chain structure.

Description

technical field [0001] The invention belongs to the field of particle material mechanics research, and specifically relates to a contact force measurement test device and a use method of a particle material force chain structure. Background technique [0002] Granular material is a complex system formed by the interaction of a large number of discrete solid particles, which widely exists in nature, such as railway ballast, rockfill, dam and debris flow. Granular material is a form of matter between solid and liquid, so it has both the characteristics of both and has its own unique properties, such as the sensitivity of granular materials to external small effects, nonlinear response and self- Complex mechanical properties such as tissue behavior. Scholars engaged in basic research in physics and mechanics have carried out precise experiments and theoretical studies on the mechanical properties of dense granular materials, and the research on the system balance, motion laws ...

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Problems solved by technology

For the electronic balance weighing method, although the accuracy of the electronic balance has been greatly improved, due to the need to move the device position during the measurement process, the underlying particles will inevitably rub against the contact paper, resulting in the redistribution of the internal forces of the particles ; For the carbon paper indentation method, due to the limited sensitivity of the carbon paper, it is difficult to leave clear marks on the white paper only by the weight of the particles, so external force is needed to enhance the indentation effect in the test, and because the carbon paper indentation method can only consider The normal force of interlayer particles cannot be described for the tangential force of interlayer particles and the contact force between particles in the same layer; for fluorescence confocal imaging, it is applicable when studying fine structures such as cells and droplets, but Its observation field of view is small, and usually it can only observe samples on the order of hundreds of microns; for magnetic resonance imaging, it takes a long time in the imaging process, and it is impossible to achieve real-time and dynamic observation of the force chain evolution of the system , and the granular material system is relatively complex, and the 3D image processing program for quantitative analysis of force changes between particles needs to be further developed; as for the photoelastic experimental method, it is mainly suitable for the full picture of the two-dimensional particle contact force and position distribution, and cannot be used for three-dimensional research. And the sample material is limited

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