Composite Fatigue Simulation with Subroutine in ABAQUS Part1

Composite Fatigue Simulation with Subroutine

In this package, we try to teach you step by step from the theory of the problem to the final results of the simulation on composite fatigue specimens. As you know, to perform this analysis using Abaqus software, we need to use UMAT subroutine writing. To get familiarity with this subroutine, you can purchase the subroutine training package of UMAT and VUMAT through our website. This training package helps you to easily perform the analysis you need in this area. Consequently, the following is a detailed description of this workshop.

Introduction to Composite fatigue

Fatigue life is defined as the loading cycle’s number (stress) of a specified character. That is a specimen sustains before happening any kind of failure. We can determine the composite fatigue life by the strain, stress, or energy approach. Due to the increasing growth of science and industry, there is a need to develop advanced materials with more profits. Composite materials due to higher efficiency and economic benefits have become a suitable alternative to traditional materials in various industries. Therefore the development of these materials by understanding how to produce and study their properties. As how to calculate the final life of fatigue for them is essential.

 Workshop 1 part 1: Theory

In the first part of this workshop, we first mention the importance of material fatigue. To check for fatigue in composite materials you need to know how to write subroutines. In the following, we will introduce how subroutine works. The theories that govern this subroutine writing, is the theory of “Shokrieh”(for more information, you can refer to this article).

The equations in this theory are based on the “Hashin” criterion. We explained it in this package’s part. In this theory, we have dealt with how to calculate the final

composite Fatigue Life in three dimensions based on the loading cycle’s number.

Workshop 1 part 2: Subroutine writing

In this part, we have presented how to write subroutine UMAT in Fortran language based on the flowchart provided in the initial part to calculate the amount of fatigue and final composite fatigue life.

Firstly, the loading method in this example is periodic and based on the number of loading cycles. we calculate the reduction of properties and its effects on the life of the model. In addition, how to define the parameters, define the initial values, and writing the relationships in Fortran code we completely taught.

Due to the fact that composite materials consist of matrix and fiber. similar conditions have been studied separately for fatigue in both material’s parts.

Workshop 1 part 3: Implement modeling in Abacus software

In the last part, we will go to the Abaqus software and explain how to implement the written subroutine on the model designed in the software. The required settings for each module are trained. Finally, this subroutine will be able to display the final composite fatigue life, behavior of the material, including the reduction of elastic properties, strengths along with other parameters such as stress, strain, displacement, fatigue failure criteria in different modes as output. The written subroutine can be used for a variety of complex to simple models.

If you are not familiar with this subroutine, you can see some information about this subroutine in ABAQUS documentation. However, you can get advanced teaching about these types of subroutines by purchasing these two packages   “UMAT Subroutine (VUMAT Subroutine) introduction” and Advanced UMAT subroutine(VUMAT subroutine) in ABAQUS package.