Construction method of 3D polycrystalline microstructure material model based on FEAP

Abstract

The invention discloses a method for constructing a three-dimensional polycrystalline microstructure material model based on FEAP, which comprises the following steps: pre-texturing a three-dimensional polycrystalline Voronoi geometric model; The inp file is translated into input file under the FEAP software, and the 3D polycrystalline microstructure is modeled geometrically. Based on Fortran program running platform, UMAT, the user material subprogram of St. Venant Kirchhoff crystal model and crystal elasto-plastic model, is added to the model library of FEAP software, and is integrated withFEAP to obtain the material model of three-dimensional polycrystalline microstructure. The mechanical model of three-dimensional polycrystalline microstructure is obtained by assigning different crystal orientation to different grains. The validity of UMAT is verified by finite element mechanical simulation. The invention completes the compilation of the user material subprogram UMAT of the two material models and carries out the validity verification, which provides the theoretical basis for the homogenization research of the polycrystalline material.

Description

technical field [0001] The invention belongs to the research in the fields of material mechanics and structural mechanics, and specifically relates to a method for creating a three-dimensional polycrystalline microstructure material model based on FEAP. The present invention is a numerical model that can describe the microstructure and deformation mechanism of polycrystals with BCC structure. It can perform mechanical analysis on BCC structure metal materials from the microscopic scale, and can be used to predict the forming of BCC structure metal materials. It has a certain engineering practical significance. Background technique [0002] Metal materials are formed through crystallization, and they play an irreplaceable role in many engineering fields. Due to the complex crystallization method, there are certain differences in the crystals generated under the control of different crystal nuclei, so it is also called polycrystalline material. The complex crystallization me...

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Problems solved by technology

So far, crystal geometry modeling has been developed for decades, and it is nothing more than the following methods: (1) Treat each unit as a single crystal; this modeling method is the simplest, but the unit division is often hexahedral regular units, Moreover, the polycrystals formed by these units are all regular shapes, which cannot highlight the real microstructure of the crystals from the geometric shape; for example, Pi Huachun and Wang Qi simulated the crystal geometry in this way

(2) Take the Gaussian integral point at the same position on each unit to represent a group of grains; it mainly solves the problem by integrating the Gaussian integral point, so it cannot reflect the internal crystal lattice rotation, etc. change, with strong limitations

(4) Construct the geometric shape of the crystal grains through the automatic cell generator. This method can generate a geometric shape similar to crystal crystals, but due to its automatic generation, researchers cannot freely control it, so it is also has great limitations

(5) Obtain the surface model of the sample through scanning electron microscope photos and metallographic images, and then follow the obtained model to build a similar grain model; the geometric shape of the grain obtained in this way is the closest to the real one, but it does not have the general nature, and the modeling method is complicated and the workload is heavy, so it cannot be popularized

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