Implementation Of Functionally Graded Material In ABAQUS Subroutines

Functionally graded material is a new composite that combines a variety of materials according to certain laws.The structure and physico-mechanical properties of the functionally graded materials change according to certain rules in order to integrate the advantages of material components.It is a promising new material of which the mechanics problem is a hotspot in the fields of materials and mechanics.Although different models have been used to study the compositiondistribution,physical parameters and mechanical properties of the functionally graded material,practical and widely usedmodels which could master the nature of thechanging law ofthe functional gradient material properties are still lacking.Moreover,studies on the eatablishment ofmaterial library of functional gradient material in the finite element programand applications of these mechanical modelson engineering practiceare still relatively few.Based on the understanding of the inherent causes of changing laws of physical-mechanical properties,relationships between material composition distributionand physical parameters of the functionally graded materialareestablished by the rational describination ofthe material componentsdistribution.Then,secondary development of newly built models are carried out in ABAQUS.In this way,the material library of the functional gradient material isestablished and the reliability of the modelis verified.The main contents of this paper are as follows:(1)Based on the summaryof mechanical researchesof functionally graded material,a simple and reasonabledistribution function of material composition are selected.For the mechanical problems of functionally graded material withuniform load and thermal-mechanical coupling effects,a set of mechanistic models with strict theory and simple form are explored based on the Mori-Tanaka method;(2)For the mechanical problem of the functionally graded material under uniform load,the component distribution function and the mechanics model based on the Mori-Tanaka method are establishtaking a thick-walled tube as an example.Then,the secondary development in UMAT with FORTRAN is proceeded and compariedwithanalytical solutions of the Mori-Tanaka method,the Reuss method,the Voigt method and the numerical solution of the layered modeling of the finite element method.The correctness,stability and accuracy of the established model and the corresponding UMAT subroutineare verified;(3)For the mechanical problem of the functionally graded material under the thermal-mechanical coupling effects,the thick-walled tube was used as an example to establish the thermodynamic coupling model.By the secondary development in UMATHT,the correctness,stability and accuracy of the established model and the corresponding UMATHT subroutine are vertified comparing with the analytical solution of Mori-Tanaka method and the numerical solution of the layered modeling of the finite element method.