Redevelopment Of MSC.Marc For Enriched Singular Crack Element

The enriched finite element method possesses the advantages of better convenience of obtaining the fracture parameters and high precision. Adding the enriched singular crack elements into the element library of commerce FEM software will play a significant role in the fine fracture analysis of Solid Rocket Motor containing cracks. Redevelopment of MSC.Marc for 2D/3D enriched singular elements for crack analysis in elastic and viscoelastic media has been done based on the enriched finite element method in this dissertation. The main works are summarized as follows:The technology of redevelopment provided by MSC.Marc is illustrated. And the user subroutine of user-define element is explained in detail. The principle and format requirement of programming is introduced. At last the redevelopment process for enriched singular element is entirely programmed.The FEM formulation is derived for 2D crack problems in elastic media. Subroutines for linear elasticity 2D enriched singular element have been developed through the redevelopment interface of user-define element provided by MSC.Marc. The obtained achievement has been used to analyze an example of 2D crack problem. The influences of Gauss integration point and the type of plane hypothesis problem on numerical results are discussed.The 3D enriched singular element is established for 3D crack problems in elastic media. Similar to the 2D enriched singular element, subroutines for 3D enriched singular element have been developed on the platform of MSC.Marc. And the achievement is used to analyze an example of 3D crack problem. The stress intensity factor of this example is obtained as the fracture parameter.The asymptotic displacement field at 2D/3D crack tip in viscoelastic media is obtained using the elastic-viscoelastic correspondence principle. The 2D/3D enriched singular elements are established for 2D/3D crack problems in viscoelastic media. Using the redevelopment capacity of MSC.Marc, the user subroutines for 2D/3D enriched singular elements have been compiled based on the enriched finite element method in viscoelastic media. And the examples of 2D/3D crack problems are used to examine the validity and accuracy of the programs.In conclusion, redevelopment for 2D/3D enriched singular elements has been done for 2D/3D crack problems both in elastic and viscoelastic media based on the platform of MSC.Marc. The obtained achievements have great values for the fracture analysis of Solid Rocket Motor using the enriched singular elements.