Why ANSYS and not Abaqus?

In complex problems like blasting, analytical solutions are extremely hard to obtain. Thus, numerical methods must be employed. AUTODYN, LS-DYNA and Abaqus are all general-purpose finite element analysis (FEA) software, which are the suitable alternative choices. A brief discussion of each of this software is given.

ANSYS was created in 1970 by Dr. John Swanson (Swanson Analysis Systems, Inc.). ANSYS version 12 is used in our project. ANSYS Multiphysics software are non exportable analysis tools incorporating pre-processing (geometry creation, meshing), solver and post-processing modules in a graphical user interface (GUI).

ANSYS AUTODYN software is an explicit analysis tool, which is especially suited to the solution of interaction problems of different systems of structures, fluids and gases together as found in blast applications. AUTODYN software allows different solvers such as Lagrange and Euler to be used together in the same model. Users of ANSYS AUTODYN are able to complete simulation projects with significantly less effort, less time and lower total cost. The high productivity is a result of the easy to use, quick to learn intuitive, interactive graphical interface implemented in ANSYS AUTODYN. Additional time and effort savers in problem set-up and analysis are provided by automatic options to define contact, coupling interfaces and minimizing input requirements with the use of safe logical defaults.

Likewise LS-DYNA (by Livermore SoftwareTechnology Corporation) is also capable of simulating complex real world problems. Its core-competency is in highly nonlinear transient dynamic finite element analysis (FEA) using explicit time integration. LS-DYNA comes with LS-PrePost and LS-OPT. LS-PrePost is an advanced interactive program for preparing input data for LSDYNA and processing the results from LSDYNA analyses. LS-OPT allows the user to structure the design process, explore the design space and compute optimal designs according to the specified constraints and objectives.

With collaborative effort between ANSYS and Livermore Software Technology Corporation, the ANSYS LS-DYNA was developed in 1996. Because ANSYS LS-DYNA is created from the same powerful technology as ANSYS, it is easy to combine with other ANSYS products. So both AUTODYN and LS-DYNA are parts of the full version of ANSYS Multiphysics.

The other powerful finite element analysis software, which is popular with academic and research institutions is the Abaqus. This is a commercial software package developed by HKS Inc of Rhode Island, USA. The Abaqus product suite consists of three core products: Abaqus/Standard, Abaqus/Explicit and Abaqus/CAE. Abaqus/Standard is a general-purpose solver using a traditional implicit integration scheme to solve finite element analyses. Abaqus/Explicit uses an explicit integration scheme to solve highly nonlinear transient dynamic and quasi-static analyses. Abaqus/CAE provides an integrated modeling (preprocessing) and visualization (post processing) environment for the analysis products. The Abaqus products use the open-source scripting language Python for scripting and customization. Abaqus/CAE uses the fox-toolkit for GUI development. Abaqus is used in the automotive, aerospace, and industrial product industries.

Both ANSYS and Abaqus are powerful FEA software and either of them could serve our purpose in our project. Nonlinear analyses in both packages are extremely powerful. Both has flexibility i.e. the programs can be adapted to your specific needs. Both packages offer 64-bit software at no extra charge. ANSYS' support is through their Value Added Sellers (VARs) whereas Abaqus' support is direct. But both packages offer good support. However, there are some minor differences between the two which are listed below:

1. ANSYS is more easy to use than Abaqus. In particular the ANSYS Workbench is preferred by engineers and the industry people because it is easier to use. ANSYS does not require users that necessarily understand either mechanics or finite elements. On the other hand, Abaqus is less user friendly than ANSYS and needs a deeper understanding of mechanics and finite elements.

   Most engineers in the field have no use for nonlinear mechanics and have very little understanding of material behaviors beyond linear elastic. Material data are also hard, if not impossible, to get. So, even if a problem is best tackled by an advanced material model, the prudent choice is to go linear elastic, linear buckling etc. That is something ANSYS does well with minimal user input; no mesh generation hassles, complex geometries easily handled, etc. It seems ABAQUS is more popular with academic and research institutions, perhaps due to the wide material modeling capability, and the program's ability to be customized.

2. Although both packages are similar in capabilities but Abaqus is more expensive than ANSYS. In addition, the Abaqus software is licensed on an annual basis. A renewal fee has to be paid each year. ANSYS supports multiple processors at no extra charge, but Abaqus only supports running on a single processor unless you purchase an add-on which will allow you to take advantage of multiple processor on one or more machines (distributed computing).

3. Some users suggested that ANSYS’s GUI (especially the geometry input) is better than that in Abaqus. In addition, ANSYS uses APDL (ANSYS Parametric Design Language), which is more intuitive scripting language than python (open-source scripting language) used in that Abaqus. Since ANSYS is more user-friendly, it has more users than the Abaqus. So ANSYS skills may be more re-usable.

For the reasons given above, we will use ANSYS AUTODYN, instead of Abaqus.