Multiple load cases

[Haitham Abdelmoneim Mohamed AbdelMalek]

Hi, I am trying to perform a static displacement loading on a concrete beam after impact drop weight. I used *INCLUDE card in the impact model and I added the static loading model. Then, defined *Case card in the impact model and i am getting this error" Try executing with "case" as a command line option (no quotes) to
turn on the built in case handling capability". 

Can someone help with this?. 

[James M. Kennedy]

Dear Haitham,

 

Some notes that may be of interest.

 

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Please look at multistage, multistep, and restart features:

 

http://www.dynasupport.com/faq/metal-forming/how-do-you-perform-a-multiple-step-analysis

 

http://www.d3view.com/multistage-dependent-or-independent-simulations/

 

Bala, S., "Stress Initialization in LS-DYNA: A Short Overview", Livermore Software

Technology Corporation, Livermore, California, October, 2009.

 

http://www.feapublications.com/pdf/StressInitialization.pdf

 

http://ftp.lstc.com/anonymous/outgoing/jday/restart.pp

 

http://www.findthatpowerpoint.com/search-40268-eDOC/download-documents-multi-stage-sheet-metal-forming-using-ls-dyna.ppt.htm

 

Wang, C., Geijselaers, H.J.M., and van den Boogaard, A.H., “Multi-Stage FE

Simulation of Hot Ring Rolling”, 11th International Conference on Numerical

Methods in Industrial Forming Processes (NUMIFORM 2013), Vol. 1532 ,

pp. 1014-1019, Shenyang, China, July, 2013.

 

http://scitation.aip.org/content/aip/proceeding/aipcp/10.1063/1.4806945

http://doc.utwente.nl/86790/1/Multi-Stage_FE_Simulation_of_Hot_Ring_Rolling_Postprint.pdf

 

Maker, B.N., and Zhu, X., "Input Parameters for Springback Simulation using

LS-DYNA", 3rd European LS-DYNA Users Conference, Paris, France, June,

2001.

 

http://www.dynalook.com/Personally/springback_maker_zhu.pdf

 

Maker, B.N., and Zhu, X., "A Procedure for Springback Analysis using

LS-DYNA", Livermore Software Technology Corporation, Livermore,

California, October, 2003.

 

http://www.lsdyna.eu/uploads/media/Procedure_Springback.pdf

 

---------------------------------------------

 

You also may wish to consider the following. Compared with binary restart dumps, Dynain

files (keyword-format files containing results such as *INITIAL_STRESS_SOLID) offer

more transparency and control for restarting the next analysis: you can handle them just like

regular keyword files. These files can be written conveniently using "staged construction"

commands. The disadvantage of dynain files is a larger file size compared to binary restart

dumps.

 

*DEFINE_CONSTRUCTION_STAGES

 

- This keyword divides the analysis time into "stages". Each consecutive blast could be

considered as one stage. For example:

 

Stage 1 starts at time=0, ends at time=1 seconds;

 

Stage 2 starts at time=1, ends at time=2 seconds;

 

Stage 3 starts at time=2, ends at time=3 seconds;

 

At the end of each stage, a dynain file will be written.

 

The keyword file could include 3 blasts, occurring at 0 seconds, 1 second, and 2 seconds.

 

*CONTROL_STAGED_CONSTRUCTION

 

- defines which stages should be included in this run. For example, the blasts could be

analysed as a sequence of chained runs (e.g. start at Stage 2, end at Stage 2), or else all

could be done in a single run (start at Stage 1, end at Stage 3).

 

*LOAD_REMOVE_PART

 

- defines the time at which a certain part should be deleted. For example, elements to be

deleted by the first blast could be given a certain Part ID, which is deleted at time=0.5 sec.

 

Other keywords:

 

*DEFINE_STAGED_CONSTRUCTION_PART

 

Purpose: Staged construction. This keyword offers a simple way to define parts that are

removed (e.g., during excavation), added (e.g., new construction) and used temporarily

(e.g., props) during the analysis. Available for solid, shell, and beam element parts.

 

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Some acquired notes on Staged Construction that may be of some interest (attached).

 

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The simplest way may be to simply run the first stage and observe the results for that parameter

and the time. Use that time for termination when you want to do a multi-stage simulation.

 

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Sincerely,

James M. Kennedy

KBS2 Inc.

September 19, 2022

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