“Too Many Attempts” and “Less than the Minimum specified Time” Errors in Abaqus

Description

the Abaqus “Too Many Attempts” and “Time Increment Required is Less than the Specified Time” Errors

Abaqus is a user-friendly software to solve the finite element method models. The software covers a large variety of models by providing many options to. To simplify the modelling process, it uses many predefined parameters to help the engineers save time on the modelling process. However, depending on the model each might require different parameters and skipping them leads to errors in simulation.  As a result, in Abaqus, you might face many errors some of which are easy to solve, and some are difficult. The most common errors are the “Too many attempts” and “Time increment required is less than the specified time”.

Where can you check the type of the error?

You can find the errors from the message file or STL file in the Abaqus job directory. The easiest way to find the error is from the monitor section in the job manager. From the incrementation, for the “Too many attempts” error you can see that the last 5 of them were reduced. For the “Time increment required is less than the specified time” error you can see the last increment size is smaller than the defined increment in your step.  There is also a comment in the report that explains the error to you.

These two errors might occur for many reasons. They indicate that the solver tried to solve the simulation but due the process aborted due to some mistake in the model. The errors might happen because of mistakes in any module such as material properties, step, load, and mesh. Here each part is explained individually:

1-Load and Boundary conditions: While every module is important, the load and boundary condition definition in simulation have the most important impact on results. In this video, we try to explain the most common mistake that might occur in the load module that creates the errors mentioned above. This video is short and helps you find the error in your simulation quickly.

2-Material Properties: Material properties play an important role in model accuracy and processing time. In Abaqus, it is common to define the data points in a table. Abaqus uses interpolation to extract the results between each table row and to get the results out of the domain it uses the last data in the table. While inputting more data helps increase model accuracy it might cause convergence issues. To understand how many data points are required we need to understand how Abaqus uses the data to solve the model.’

3-Step and Increment: Too many attempts” and “Time increment required is less than the specified time” are two common errors in Abaqus. The errors usually occur because of mistakes in creating steps. Abaqus provides various steps such as heat transfer, general static, explicit, and implicit dynamic steps. These steps define the type of the simulation. To define these steps we need different details. Abaqus divides each step into multiple increments to solve the model. You can control the size of the increment. Thus, making a mistake leads to an error during the simulation process. To avoid these problems, you need to understand the concept of incrementation and step time. Here we first explain the initial, minimum, maximum, maximum number of increments, and max. allowed temperature change per increment. Then we will explain the common mistake in heat transfer and mechanical model by showing 5 examples. We go over each example and check the problem then we try to solve them by editing the step details.

The tutorial video

This video explains the common error called “too many attempts” and “Time increment required is less than the specified time” in Abaqus for beginners. If you feel you need to know more about the process of solving and modelling in Abaqus watch the following video:

If you are interested in learning how to change step settings to modify the incrementation please watch the following link:

The recorded video is about 10 minutes and helps you learn how to detect and fix errors.

This video is created by Reza Tangestani. For more information, please send him an Email:

rezatangestani@hyperlyceum.com

In case you would  like to know more about Abaqus!

Abaqus is an FEA software for multiple engineering purposes. Many researchers, companies, and students have been using it to simulate simple and complex models. Compared to other software, Abaqus is a flexible tool to analyze the process. Even though it has a user-friendly environment, it is not easy to learn as the license is rather expensive. Therefore, tutorial videos on this software are not easy to find or are too expensive. Before explaining the Abaqus tutorial details, we should first look at what Abaqus covers and what exactly it is. The following explanation is from Abaqus 6.14 documentation.

Abaqus/CAE  is a Complete Abaqus Environment that provides a simple, consistent interface for creating, submitting, monitoring, and evaluating results from Abaqus simulations. Abaqus/CAE is divided into modules, where each module defines a logical aspect of the modelling process; for example, defining the geometry, defining material properties, generating a mesh, submitting analysis jobs, and interpreting results.