VDload Subroutine for Movement of a Train on Railroad



VDload Subroutine for explicit model

An example of the VDload subroutine in Abaqus is provided. In this tutorial we explain the movement of train on a railroad track using Abaqus explicit model and VDload subroutine. We show the details of the model and  the model files are provided. You can check the Abaqus subroutine to learn how we implemented the load of each wheel. The geometry for each component is created. The material properties were assigned to each component. In the assembly section we show how they are together. We used explicit step with mass scaling option. We mesh each component based on each component application. In load and BC section we discuss the necessary details as well as gravity force. We explained each part with detail so you can understand the model.

Please note we used a large value for mass scaling option to decrease computational time. If you need to, you can decrease it. 

Please note this model requires at least 4 GB ram.

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 In this video, we avoid giving too many details so you can easily use the product. Here you can find the following files:

Abaqus files: CAE, ODB, INP, FORTRAN, and JNL

PowerPoint files that contain more details.

Video files: How to create this model, PowerPoint presentation.

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Vdload subroutine

VDload subroutine code is one of the most simple subroutine codes you can start learning. It is a subroutine for the Abaqus explicit which has many applications. One of the advantages of using Explicit Solver is its strong capability in contact analysis. In some cases, such as the movement of train wheels on a railroad track, which requires modelling various components or simulating the movement of a vehicle on a bridge, it is beneficial to use the explicit solver. To define the complex load distribution or movement on components for explicit models the VDload subroutine is helpful. You can define complex mechanical loads for your model with minimum effort. The use of VDload is similar to Dload and most of the variables are the same.

If you think you need more background, it might be a good idea to see the other video about the subroutine (Please click here). To use subroutine we need to use the FORTRAN code and also Abaqus needs to be linked to Intel FORTRAN. The video is short so you can learn this in less than 15 minutes and you will have the output and Abaqus CAE file.

More Details About Abaqus

Abaqus is an FEA software used to analyze models with high complexity. The provided option by this software creates a great environment for studying various models. Not even solid mechanics but also thermal and fluid mechanic models can be simulated in this software. It is worth mentioning that the fluid mechanic model was separated after Abaqus 6.16 and since version 2017 the company started to develop an independent solver for it. In order to increase the complexity of models, engineers can use FORTRAN to develop subroutine code and Python to create a model by scripting. Here we provide a simple description to explain how these two features help you to develop a model.

Scripting by Python:

Imagine you want to create a part with holes randomly distributed inside it. You need to bring a calculator and a piece of paper to find some random numbers to find the center and radius of those holes. The other option is to use Matlab code or any other coding language to find those random values. However, after finding those values you still need to create those holes inside your models. You need to modify your part at least one time per hole. Fortunately, Abaqus provided Python scripting to avoid this. You can easily create your code there and use the provided function to create and modify those holes inside your part. Consequently, you don’t need to do it by clicking and modifying your part. You can develop a code in Python to do the job for you.

Subroutine for Abaqus:

Now, you created your complex part and now you are ready to define your material properties, boundary condition and loads. However, you notice your material properties are very complex and it changes over time. Even if you didn’t have this problem, you would need to change the value of time-dependent on material properties. You look at the Abaqus feature and think there is no way you can do it. In fact, your model should change during the process. Your values are not just a simple number and you need to make them as a function of time and other variables. Here is the time you need to use subroutine to define those complex properties in your model. You need to use the proper function known as Subroutine and define your function there and run that by your model.



Easy learning

1 review for VDload Subroutine for Movement of a Train on Railroad

  1. HyperLyceum Team (verified owner)

    This helps you a lot to learn Vdload subroutine and the details are enough to propose as a project

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