Learning Forum

[1802039]

What is the difference between working within LS Dyna Prepost-RUN and Workbench?

I am completely new in this field.

Thank you.

[Ram Gopisetti]

 

Hi, 

LS-DYNA PrePost functions within a dedicated layer, handling both pre- and post-processing tasks, including model setup with native card support and result parsing. LS-RUN, on the other hand, is responsible for executing files such as .k, .dyn, .key, etc. generated from the above stage, and offers options to run and manage simulations, either locally or across a cluster.

WB LS-DYNA, while maintaining control over a limited set of cards and capabilities, still provides the flexibility to configure control models and modify cards using command snippets, much like how Mechanical interacts with APDL.

I know it is a top-off comparison for more details check with your local ANSYS channel partner. 

Cheers, Ram 

 

 

[Alex Rycman]

Hello, 

When working with LS-DYNA, you have the option to use either Ls-PrePost or Ansys Workbench to preprocess the model/post process the results, each offering distinct advantages. In both cases LS-DYNA as a solver is the same. 

LS-Prepost is a traditional preprocessor that is keyword-based, allowing users to edit and manage input files directly. It is available for free and can be downloaded for personal use. This approach is suitable for users familiar with LS-DYNA's keyword workflow and those who prefer a more hands-on method of managing simulation inputs

On the other hand, Workbench provides a more user-friendly, CAD-like environment with a push-button interface, making it easier for users who are accustomed to Ansys Mechanical workflows. Workbench allows users to leverage various tools such as Spaceclaim Design, Exploration, and optimization features, providing a more integrated and streamlined workflow. It is particularly beneficial for users who prefer a graphical interface and want to take advantage of Workbench's capabilities in pre and post-processing

Thanks,
Alex 

[Dennis Chen]

 

 

I know we have Ansys Employees has already offered really good answers but if it’s ok, I would like to add a comment here because I actually use both LSPP and Workbench LS-Dyna to pre/post process models in LS-Dyna.

What I encourage you to think about is instead of asking the questions “what’s the difference between these tools or which one should I use?”, we can ask the question “how can I combine these tools together into a coherent work flow and process such that I am now more effective AND efficient than I could have been using only one of these tools”. 

In that regard, I do the following and I hope this helps you

1) I use LSPP to prepare keywords such that I can save them in a text editor such as VS code and then insert into my workbench model

2) I use workbench to mesh and set up the basics of the model.   Each workbench action corresponds to a keyword in the input deck and our job is to know exactly which button in WB is generating what keywords (sometimes it’s a combination) so using WB is no different than using LSPP in the end

3) workbench is geometry based so it lacks capabilities such as creating a node in space, or finding the node number of a CNRB (remote point) but there are python scripts that I’ve created to find these node numbers, etc.  So even weakness of WB can be overcome with additional studying

4) write out the input file but never solve in WB because solving there is just not clean right now and because we want to post process in LSPP 

5) generate default card templates such as default control cards or database cards.   This is no different from using *Include in LSPP

5) always post process in LSPP becuase it has a very easy to use post processor honestly and is extremely capable and has built in journal files to allow automations, among many other key functionalities that’s currently not present in workbench.

Below 2 videos are what I’ve made on this topic and I hope it helps you

Introduction to LS-Dyna (first 20 minutes touched this topic)

https://www.youtube.com/watch?v=53-NEshyEnE&t=1983s

don’t use default control/database cards in workbench

https://www.youtube.com/watch?v=qhp1dvAcBgc