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Differences between ABAQUS Standard & ABAQUS Explicit

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Abaqus Explicit or Abaqus Implicit?

Have you ever wondered, “Abaqus Standard or Abaqus Explicit?” It’s a common question when you’re gearing up for your analysis. Aside from the specialized CFD solver (Abaqus/CFD) designed for fluid problems, Abaqus revolves around its two core analysis modules: Abaqus Implicit and Abaqus Explicit. In this post, we’re about to unveil the key differences between these two solvers and help you pick the one that’s just right for your analysis needs. Stick around with CAE Assistant!

abaqus standard

Abaqus implicit and Explicit Solvers | Abaqus standard vs implicit!

First, I have to say that there are no differences between Abaqus Standard and Implicit. In fact, these are two names for one solver. The main discussion is about Abaqus Implicit and Abaqus Explicit solvers.

These solvers are based on two approaches in FEM analysis, namely implicit (for Abaqus/Standard) and explicit. The distinction between the two different numerical approaches makes it possible to understand which solver to use.


Read More: Debugging of ABAQUS errors


In the case of the implicit method, equilibrium is enforced between externally applied load and internally generated reaction forces at every solution step (Newton Raphson method).
In the case of the Abaqus explicit method, there is no enforcement of equilibrium. But this does not mean that explicit is not accurate. You can minimize its deviation from equilibrium to almost zero by increasing the number of solution steps, i.e. reducing the time step size.
We can list the main differences below:
Abaqus Implicit is unconditionally stable.
Implicit schema is incremental as well as iterative. However, explicit schema is only incremental.
In terms of cost per Increment, it is costly for implicit and cheaper for explicit. Disk space and memory usage are typically much smaller than that for implicit. The explicit method shows great cost savings over the implicit method as the model size increases:

Abaqus implicit and Abaqus explicit diagram

Therefore, Abaqus/Standard(or Abaqus implicit) must iterate to determine the solution to a nonlinear problem but Abaqus/Explicit determines the solution without iterating by explicitly advancing the kinematic state from the previous increment. Read More: Quasi Static

Explicit or Standard, Which one should I use?

For many analyses, it is clear whether Abaqus/Standard or Abaqus/Explicit should be used. For example, Abaqus/Standard is more efficient for solving smooth nonlinear problems; on the other hand, Abaqus/Explicit is the clear choice for high-speed dynamic analyses such as crash analysis or drop test. There are, however, certain problems that can be simulated well with either program.

Typically, these are problems that usually Abaqus/Standard can solve but may have difficulty converging because of contact or material complexities, resulting in a large number of iterations. For example, in problems where very complex contact conditions or very large deformations are present. Such analyses are expensive in Abaqus/Standard because each iteration requires solving a large set of linear equations.

Main types of Abaqus analysis | choosing Abaqus standard or explicit

In the video below, prepared by the CAE Assistant team, see the complete comparison between the Abaqus standard solver and the Abaqus explicit solver:

 

In this post, we have tried to explain ‘Abaqus standard and Abaqus explicit’ thoroughly so that you can choose the right solver for your needs. Also we clarified there is no difference between Abaqus standard vs implict. they typically refer to the same solver.

additionally, It would be useful to see Abaqus Documentation to understand how it would be hard to start an Abaqus simulation without any Abaqus tutorial. Also, please share your views with the CAE Assistant experts in the comment section. We really appreciate your feedback, as it helps us improve our tutorials and fulfill all your CAE needs without requiring additional tutorials.

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✅ Module by Module Training                                  ✅ Standard/Explicit Analyses Tutorial

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You can have the PDF of this post by clicking on CAE Assistant- Abaqus implicit or Abaqus explicit

Which of the Explicit or Standard solvers is more suitable for my problem?

Abaqus/Standard is a good choice to solve static, low-speed dynamic, steady-state transport, or smooth nonlinear analyses. On the other hand, Abaqus/Explicit is the clear choice for quasi-static events such as the rolling of hot metal, severely nonlinear behavior such as contact, transient response, or high-speed dynamic analyses such as crash analysis or drop test. There are, however, certain problems that can be simulated well with either program.

What are the main differences between Explicit and Implicit Solvers in Abaqus?

  1. Implicit is unconditionally stable.
  2. Implicit schema is incremental as well as iterative. However, the explicit schema is only incremental.
  3. In terms of cost per increment, it is costly for implicit and cheaper for explicit.
  4. Disk space and memory usage are typically much smaller than that implicit: look at this diagram.

What is the difference between the solving strategy of Abaqus/Standard and Abaqus/Explicit?

These solvers are based on two approaches in FEM analysis, namely implicit (for Abaqus/Standard) and explicit. The distinction between the two different numerical approaches makes it possible to understand which solver to use. Abaqus/Standard must iterate to determine the solution to a nonlinear problem, but Abaqus/Explicit determines the solution without iterating by explicitly advancing the kinematic state from the previous increment.

What methods are used to analyze problems in Implicit and Explicit Solver?

In the case of the implicit method, equilibrium is enforced between externally applied load and internally generated reaction forces at every solution step (Newton Raphson method).

In the case of the explicit method, there is no enforcement of equilibrium. But this does not mean that explicit is not accurate. You can minimize its deviation from equilibrium to almost zero by increasing the number of solution steps, i.e. reducing the time step size.

How can we solve problems that involve several analysis stages?

Abaqus provides a useful capability for simulations involving several analysis stages. In this ability, the user can start a simulation in Abaqus/Explicit. Then the results at any point within the solver run can be transferred as the starting point for continuation in Abaqus/Standard. The user will define new model information during the import analysis.

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2 thoughts on “Differences between ABAQUS Standard & ABAQUS Explicit

  1. Avatar of turkce turkce says:

    Good write-up. I definitely appreciate this site. Keep it up! Elle Tanny Kirtley

  2. Avatar of sara.nik-4868 sara.nik-4868 says:

    Hello, thank you for this article. I needed to choose one of these two solver to solve my problem. This article helped me choose the most suitable solver. thank you

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