Implementation of Finite Strain-Based Constitutive Formulation in LLLNL-DYNA3D to Predict Shockwave Propagation in Commercial Aluminum Alloys AA7010

• Published in: IOP conference series. Materials Science and Engineering 2016-11, Vol.160 (1), p.12023
• Main Authors: Nor, M K Mohd, Ma'at, N, Kamarudin, K A, Ismail, A E
• Format: Article
• Language: English
• Subjects: Algorithms; Aluminum base alloys; Constitutive models; Equations of state; Mathematical models; Motivation; Plate impact tests; Strain; Tensors
• ISSN: 1757-8981; 1757-899X
• DOI: 10.1088/1757-899X/160/1/012023

The constitutive models adopted to represent dynamic plastic behaviour are of great importance in the current design and analysis of forming processes. Many have studied this topic, leading to results in various technologies involving analytical, experimental and computational methods. Despite of this current status, it is generally agreed that there is still a need for improved constitutive models. There are still many issues relating to algorithm implementation of the proposed constitutive model in the selected code to represent the proposed formulation. Using this motivation, the implementation of a new constitutive model into the LLNL-DYNA3D code to predict the deformation behaviour of commercial aluminium alloys is discussed concisely in this paper. The paper initially explains the background and the basic structure of the LLNL-DYNA3D code. This is followed by a discussion on the constitutive models that have been chosen as the starting point for this work. The initial stage of this implementation work is then discussed in order to allow all the required material data and the deformation gradient tensor F to be read and initialised for the main analysis. Later, the key section of this implementation is discussed, which mainly relates to subroutine f3dm93 including equation of state (EOS) implementation. The implementation of the elastic-plastic part with isotropic plastic hardening, which establishes the relationship between stress and strain with respect to the isoclinic configuration Ω̄i in the new deviatoric plane, is then presented before the implemented algorithm is validated against Plate Impact test data of the Aluminium Alloy 7010. A good agreement is obtained in each test.