Weight measuring method of grain in silo based on finite element analysis

Abstract

The invention provides a weight measuring method of grain in a silo based on finite element analysis, and relates to the field of grain measurement. The measuring method includes the following steps that a triaxial compression test and an isotropic constant-pressure compression test are conducted on the grain, and the parameters of a grain modified Cambridge model are acquired by calculation, wherein the parameters include a critical state stress ratio, an isotropic expansion index, a logarithmic hardening modulus and a Poisson's ratio; the grain pile in an uncompacted state in the silo is divided into N layers; each layer of the grain pile is divided into M units from the center to the exterior, wherein the central axes of the M units are collinear with the central axis of the silo; the strain and stress relationship of each unit conforms to the modified Cambridge model; the modified Cambridge model is solved by means of ABAQUS, the height of each unit of the grain pile in a compacted state is obtained, the volumetric strain of the N*M units in the compacted state is calculated, the densities of the N*M units are calculated, the weight of each layer of the grain pile is calculated, and the total weight W of the grain pile in the silo is calculated. The measuring method has the advantages of being simple, short in time consumption, accurate in measuring result and high in precision.

Description

technical field [0001] The invention relates to the field of grain measurement, in particular to a method for measuring the weight of rice in a silo based on finite element analysis. Background technique [0002] The silo is one of the main warehouse types for storing rice. It is a grain storage container with the highest degree of mechanization and is mainly used for storing bulk grain. Rice is a typical granular body. When stored in a silo, its static properties are elastic-plastic. The rice will be supported by its own weight, internal friction, and the wall and bottom of the silo. The interior of the rice pile produces stress due to these forces, resulting in elastic and plastic deformation, the volume of the rice pile shrinks, and the density increases; as the depth of the grain layer increases, the compressive stress and shear stress of the rice pile increase, and the volume strain increases. As the grain increases, the density also increases; due to the influence of ...

AI Technical Summary

Problems solved by technology

A new method of measuring the density distribution of grain piles is being studied. Some researchers use microwaves to detect the density of grain piles. This method is to measure the dielectric constant when microwaves pass through grain piles. The relationship between dielectric constant and density To obtain the density of the grain pile, but this method cannot measure the density in the depth of the silo, because the microwave reaches the depth of the grain pile and is easily disturbed. At present, it can only measure the density of the grain pile at a depth of two meters.

There are also researchers who install force sensors on the wall and bottom of the silo, and calculate the total weight of the stored grain from the stress distribution of the silo wall and bottom, but this method has two problems. Establish an accurate mathematical model, otherwise the measurement error will be large, and the second is that the cost is high and it is difficult to promote

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