基于应变梯度理论和面积坐标有限元的管线钢微观组织尺寸效应研究

发布时间：2018-09-12 07:43

【摘要】：研究在微细尺度下,有效模拟金属材料变形尺度效应的数值方法。将四边形面积坐标法与MSG应变梯度理论的本构方程相结合,通过用户子单元UEL加入到ABAQUS的数值模拟中。在有限元模拟过程中,采用传统八节点等参元时常遇到网格严重畸变的问题,而基于四边形面积坐标方法的单元却在网格严重畸变时仍然能够保持较高的精度,在非线性问题中有广阔的应用前景,而且经典理论无法解释试验中观察到的尺寸效应现象,因此采用MSG塑性应变梯度理论的本构方程解决尺度效应问题。应用文献中的数据对电抛光镍做数值模拟,以验证新的理论模型的正确性,对JX-2管线钢做试验研究,并对所得的铁素体、贝氏体、铁素体和贝氏体的双相体三种微观组织进行数值模拟,对比试验和模拟结果证明新的理论模型在工程中具有良好的可应用性,较传统塑性理论能更好地预测试验结果。
[Abstract]:A numerical method for simulating the scale effect of metal material deformation at micro scale is studied. The quadrilateral area coordinate method is combined with the constitutive equation of MSG strain gradient theory, and the user subelement UEL is added to the numerical simulation of ABAQUS. In the process of finite element simulation, the traditional eight-node isoparametric element often meets the problem of serious mesh distortion, but the element based on quadrilateral area coordinate method can still maintain a high accuracy when the mesh is seriously distorted. There is a broad application prospect in nonlinear problems, and the classical theory can not explain the phenomenon of size effect observed in the experiment. Therefore, the constitutive equation of MSG plastic strain gradient theory is used to solve the scale effect problem. In order to verify the correctness of the new theoretical model, the numerical simulation of electropolishing nickel was carried out by using the data in the literature. The experimental study on JX-2 pipeline steel was carried out, and the ferrite, bainite, and bainite were obtained. Three kinds of microstructures of ferrite and bainite are numerically simulated. The comparison and simulation results show that the new theoretical model has good applicability in engineering and can predict the test results better than the traditional plastic theory.
【作者单位】：北京科技大学数理学院;
【分类号】：TG142.1

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