Introduction to USDFLD and VUSDFLD Subroutine

Introduction to USDFLD and VUSDFLD Subroutine

Using USDFLD and VSDFLD enables you to simulate models in which the properties of their materials are related to some parameters or conditions. For example, modeling an adhesive joint whose cohesive damage properties are related to a parameter that is not in Abaqus GUI. Analyzing soil that the elastic modulus is related to its depth is a practical example. You will learn how to code these two subroutines as well as the differences between them. In addition, you will be able to change one of them to another one. To sum up, using this subroutine there will be no limitation for you to simulate models containing variables function to other parameters. In addition, we explain how to get access to the interfaces of subroutines, essential settings in GUI, getting familiar with each subroutine’s parameters, etc.

USDFLD and VSDFLD have a very broad scope, and in general, you can use these two subroutines whenever you a parameter in the software material environment that you want to rely on another variable. The difference between the two subroutines is in their solver, where Abaqus standard and Abaqus Explicit solvers use USDFLD and VUSDFLD, respectively. You will learn about how to connect Abaqus and subroutine as well as an overview of subroutine writing in Abaqus.

Workshop 1 Simulation of elastic properties of soil in different depth with USDFLD subroutine :

In this workshop, we will use a simple example to use the USDFLD subroutine. We compare two Abaqus GUI and subroutine methods for simulating soil with changing modulus of elasticity at different depths under compressive loading. At last, we compare the results in both models.

Workshop 2 analyzing a crack path in Spherical FGM:

We will model a functionally graded material (FGM) with a crack on its spherical geometry in this workshop. The USDFLD subroutine is used since we wanted to simulate this by the Abaqus standard. In this model, pressure is applied from the inner part of an empty sphere, and the distribution of stress in this sphere is discussed. Further, the XFEM method is used to define the material for crack and to locate a crack in the Interaction module. In this exercise, we’ve also discussed parameters related to crack analysis and finally checked the results.

Workshop 3 composite shell plane explosion with a sticky connector in the layers:

In this workshop, the main subject is to use the VUSDFLD subroutine to damage an explosive structure as we used Abaqus Explicit solver. In this model, we show how to use the VGETVRM subroutine in the VUSDFLD subroutine. Furthermore, we explain utterly how to define different possible conditions based on damage numbers in subroutines of the VUSDFLD. Finally, view the deflection results and other variables in composite layers.

Workshop 4 Fatigue Cohesive analysis of two AL specimens in the adhesive single lap joint:

we will use the VUSDFLD subroutine at this workshop to simulate fatigue cohesive in a single lap adhesive joint. The evolution of the damage and the cohesive damage are described in full. It is noteworthy that we used the Benzeggagh-Kenane Fracture Criterion relationship for progressive damage as well.