Monte Carlo

 Working Directory and Extraction of necessary files

• Create a working directory in the desired location to keep the LS-OPT project file and input files, as well as the LS-OPT program output, e.g. monte_carlo.
  
• Extract all the files required for this example from download section into the working directory.

 

Project Details

1. Select the Working Directory of the LS-OPT project.
2. Select a suitable name for the file under Filename (e.g. monte_carlo). The extension .lsopt is appended by LS-OPT.
3. Description of the main task can e.g. be a suitable name for Problem Description ( in this case, Reliability analysis with Monte Carlo Method, optional) .
4. Choose a suitable name under the Initial Sampling name (e.g. Sampling).
5. Choose a suitable name under the Initial Stage name (e.g. LS_DYNA).
6. Click on the Create button to initiate the formation of the input file.

• The main GUI window of LS-OPT opens.

Home Screen Process Flowchart

1. Click on the Show task settings icon to select the optimization task and strategy.

The Task Selection window shall then open.

Define the Main Task

1. Select Monte Carlo analysis as Direct Simulation method.
2. Click on the OK button to proceed.

• After defining the main optimization task the Home Screen Process Flowchart takes its shape accordingly.

Home Screen Process Flowchart

1. Double click on the LS_DYNA box to define the solver stage in the simulation process.

The Stage dialog window shall open.

Define Stage Setup

1. Select the Setup tab.
2. Select the solver Package Name LS-DYNA.
3. For Command enter smpR7.1.2_95028 (or the respective command available on your system). On Windows, the command has to be specified using the absolute path. 
4. For Input File browse the LS-DYNA keyword file tube.k. Parameters are defined in this file by using  LS-DYNA keyword format *PARAMETER.
5. For efficient usage of the computing power from the machine, choice on handling number of concurrent jobs can be made suitable in this section. For more details see FAQ resources.

Design Parameters

1. The parameters defined in the selected Input File can be seen in the adjoining tab Parameters.

Define Histories

1. Select Histories tab.
2. Select NODOUT as a type of history under the standard LS-DYNA binary database list.
3. Enter TOP_DISP_HIST as the Name of history.
4. Select the Component as Displacement
5. Select the Direction as Z Component.
6. Select the Identifier Type as Node ID and enter 486 as node ID.
7. Click on the OK button to end the history definition.

Define Responses

1. Select the Responses tab.
2. Select NODOUT as a type of history under the standard LS-DYNA binary database list.
3. Enter TOP_DISP  as the Name of the response.
4. Select the Component as Displacement.
5. Select the Direction as Z Component.
6. Select the Identifier Type as node ID and enter 486 as node ID.
7. Select the Minimum Value of the displacement of this node in selected z-direction.
8. Click on the OK button to end the response definition.
9. Click on the OK button to proceed.

Home Screen Process Flowchart

 

1. Double click on the Setup box for the conversion of parameters to design variables of different types.

 

The Problem global setup dialog shall open.

Define Parameters

1. Select Parameter Setup tab.
2. Select the Type of both probabilistic design variables as Noise.
3. Open the Distribution settings dialog to define the distribution of variable SIGY.
4. Click on Add new distribution.
5. Enter s1 as the Distribution Name.
6. Select Normal as the distribution Type.
7. Enter 1 for Mean value.
8. Enter 0.05 for Standard Deviation.
9. Click on the OK button to end the distribution definition for variable SIGY.

10. Open the Distribution settings dialog to define the distribution of variable T1.
11. Click on Add new distribution.
12. Enter t1 as the Distribution Name.
13. Select the distribution Type as Normal.
14. Enter 1 for Mean value.
15. Enter 0.05 for Standard Deviation.
16. Click on the OK button to end the distribution definition for variable T1.
17. Click on the OK button to proceed.

Home Screen Process Flowchart

1. Double click on the Sampling box in order to define sampling settings.

A Sampling dialog shall open.

 

Define Metamodel Settings

1. Select Metamodel Settings tab.
2. Select the Pointselection method as Latin Hypercube.
3. Enter 100 for the Number of Simulation Points.
4. Click on the OK button to proceed.

Home Screen Process Flowchart

1. Double click on the Monte Carlo box.

An Optimization dialog shall open.

A Monte Carlo Analysis does not use objective functions, since no optimization is performed, but constraints.

 

Define Constraints

1. Select Constraints tab.
2. Select the response TOP_DISP to be constrained.
3. Set the Lower Bound for this response to -230.
4. Click on the OK button to proceed.

Home Screen Process Flowchart

Run LS-OPT

1. Click on the Run button on the Control Bar.
2. Select Normal Run.
3. For every stage the user has the option to observe the progress of the program execution by selecting the LED at the corner  on the Stage box. It is possible to observe the Progress and View Log for more information about the execution process.

• Correlation Matrix
• Scatter Plots
• Statistical Tools
• Histories
• DynaStats