UHYPER Subroutine in ABAQUS introduction
There are several subroutines in ABAQUS that can be used if the software’s graphics environment is inadequate. One of these is the UHYPER subroutine, which is used to define the strain energy of hyperlastic isotropic materials. This subroutine is invoked for all points referred to the subroutine and can dependent on field variable or state variable. The applications of this subroutine, which are dependent on the problem, equations, and theory, can be widely applied to industrial and academic applications.
It should be noted that if the strain energy density function of your isotropic material is determined, it is easier to use UHYPER subroutine instead of UMAT subroutine.
You can find general information about this subroutine here. If you are interested in learning more about the application of different subroutines and some basics and recommendations to write the subroutine in Abaqus, I recommend this article from the blog section.
Workshop 1: Implementation of Neo-Hookean material behavior in ABAQUS via subroutine
In this workshop, the subroutine variables are reviewed. Then, the Neo-Hookean equation is introduced and the subroutine is written and explained line by line. To implement the subroutine, some settings are required in Abaqus/CAE. In this workshop, a single element model has been loaded in the x-direction and its behavior has been analyzed using the UHYPER subroutine and Abaqus Neo_Hookean model. Finally, the results of the subroutine are verified with the UHYPER subroutine
Workshop 2: Simulation of Rigid ball pressing against a Hollow Block in ABAQUS via subroutine
A hollow block containing a cavity has been loaded by a rigid ball and all needed surfaces have contact constraints. the same Neo_Hookean model is used for this problem. After problem description, settings are defined in Abaqus CAE and compared the subroutine results with Abaqus/CAE.
The Abaqus user subroutine allows the program to be customized for particular applications unavailable through the main Abaqus facilities. You should write a user subroutine if you could not run your analysis by ABAQUS built-in models for materials, loads, properties, elements, etc., for example, if you need to model a user-defined nonlinear stress-strain relation, which is not provided by Abaqus, then look for UMAT user subroutine. A more simple subroutine is DLOAD, which allows the creation of user-defined loads. If it is your first time writing a subroutine like DLOAD, please read the Start Writing an Abaqus Subroutine: Basics & Recommendations article. After reading this post and watching this tutorial’s demo video, you will definitely decide to save time in Abaqus modelling and get this Dloadtraining package. If you have questions, ask here on our live chat on the left side of this page.