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Calculating damage in LMS Tecware ProcessBuilder

by Siemens Valued Contributor Siemens Valued Contributor on ‎09-01-2016 05:38 AM - edited

 

Calculating damage in LMS Tecware ProcessBuilder

 

With LMS Test.Lab 16A revision or higher, the LMS Tecware ProcessBuilder can be run via LMS Test.Lab tokens.

 

LMS Tecware ProcessBuilder is a graphical environment where multiple methods can be combined together to create a data processing routine. Methods that can be combined include:

  • Filtering
  • Integration/Differentiation
  • Spike removal
  • Drift removal
  • Resampling
  • Fatigue and damage calculations
  • Logic operations

 

Building a Processing Routine

 

To calculate damage from a load time history in Tecware Processbuilder, the following steps are required:

 

  1. Select Time Histories: Identify files for analysis
  2. Process Creation: Select methods to calculate fatigue damage
  3. View results: View rainflow matrices, save damage results in Excel

Select Time Histories

 

Time history file selection can be done via the menu File-Data Import, or just by drag-and-drop of time data files from the Windows Explorer to the ProcessBuilder.

 

First select some time data to process, by choosing the ‘Data Import’ icon in the upper left as shown in Figure 1. An ‘Import’ dialog box will open.

 Figure 1: ‘Data Import’ icon for selecting time histories to processFigure 1: ‘Data Import’ icon for selecting time histories to process

In the ‘Import’ dialog box, several different file types can be selected, including LMS LDSF, RPC, ASCII, etc.  Navigate to a directory containing data and double click on it to select it for processing as shown in Figure 2.

 Figure 2: ‘Import’ dialog for selecting load time historiesFigure 2: ‘Import’ dialog for selecting load time histories

Press ‘Open’ when finished. There are checkboxes for selecting entire files or individual channels to be processed. By default, all added data is to be processed.

 

Process Creation

 

Next a processing routine consisting of different methods is built.

 

Drag and drop from the ‘Input/Output’ methods (right side of screen) one ‘Input’ method and one ‘Output’ method as shown in Figure 3. These will be at the beginning and end of the process.

 

 

 

 

Figure 3: Drag and drop an ‘Input’ method and ‘Output’ methodFigure 3: Drag and drop an ‘Input’ method and ‘Output’ method

Then from the ‘Histogram Counting’ methods, drag and drop the ‘Rainflow Counting’ icon in the middle screen (Figure 4).

 

 

Figure 4: Drag and drop the ‘Rainflow Counting’ methodFigure 4: Drag and drop the ‘Rainflow Counting’ method

From the group ‘Export/Convert’ drag and drop the ‘Export Properties’ method into the process as shown in Figure 5.  ‘Export Properties’ allows data results to be exported into Excel easily.

 

 

Figure 6: Making connections between methodsFigure 6: Making connections between methods

Note: Dropping a method on an existing method in the middle area automatically connects the two methods.

 

In the end, the process should look like Figure 7.

 

 

Figure 7: Appearance of final processFigure 7: Appearance of final process

Double-clicking an individual method will open the parameters. For Rainflow Counting, adjustments can be made to the number of bins, the limits, hysteresis gate, and whether groups of channels should share the same limits.

 

To compare different loads based on their damaging behavior, the damage can be calculated based on a SN-Curve. The SN-Curve can come from a number of different sources:

 

  • Known SN-Curve parameters
  • A default SN Curve with a slope of 5. No endurance limit and no maximum tensile strength is used.
  • A material database, for example the FKM libraries from VDMA (Verband Deutscher Maschinen- und Anlagenbau e.V.)

Now press the “Run” button to run the methods as shown in Figure 8.  Methods will turn green as they are completed. 

 

 

Figure 8: Running methods in ProcessBuilder turn green as they completeFigure 8: Running methods in ProcessBuilder turn green as they complete

Viewing Results: Excel

 

The Excel file with the damage values is available using a right-click on the ‘Export Properties’ method, and select ‘Show Excel’ as shown in Figure 9.

 

 

Figure 9: Right click on ‘Export Parameters’ and select ‘Show Excel’Figure 9: Right click on ‘Export Parameters’ and select ‘Show Excel’

The Excel file contains one line per channel and a default set of attributes like path, file name, channel name, unit, statistics and damage as shown in Figure 10.  If multiple files were processed, they appear on different Excel worksheets.

 

 

Figure 10: Excel file with damageFigure 10: Excel file with damage

To change the selection of attributes, double-click on the ‘Export Properties’ method and press the button ‘Select Properties’ as in Figure 11.

 

 

 

Figure 11: Choose ‘Select Properties’Figure 11: Choose ‘Select Properties’

Either remove ‘Selected Properties’ on the right, or add more attributes from the ‘Available Properties’ area on the left. If the ‘Available Properties’ on the left is empty, a run must be processed, so that the available attributes are filled in as shown in Figure 12.

 

 

Figure 12: Properties can be selected for display in the Excel outputFigure 12: Properties can be selected for display in the Excel output

Viewing Results: Rainflow Matrices and Data Graphs

 

To view the input data time histories or the resulting rainflow matrices, right click on the ‘Rainflow Counting’ method, and select “Show data in input” or “Show data in output” as appropriate (Figure 13).  For the Rainflow Counting method, input data is the time history, while the output data is the rainflow matrix. 

 

 

Figure 13: Showing input and output data on methodFigure 13: Showing input and output data on method

After selecting ‘Show data in output’ a ‘Management of Results’ dialog box is opened (Figure 14).  Here one can view the Rainflow matrices and use the arrow buttons to scroll thru the different channels.

 

 

Figure 14: ‘Management of Results’ and viewing of dataFigure 14: ‘Management of Results’ and viewing of data

From the Rainflow matrix display, it is possible to view the cycle counts and accumulated damage.  To do so, choose ‘Analyze -> Range Pair’ from the menu (Figure 15).  An accumulated cycle display is shown, showing the amplitude of the cycles versus the number of cycles.

To see the residue, select ‘Options -> Graphic Residue’ in the Rainflow display menu.

 

 

Figure 15: Choose ‘Analyze -> RangePair’ to see Cumulative Cycle CountFigure 15: Choose ‘Analyze -> RangePair’ to see Cumulative Cycle Count

In the RangePair display, one can then switch to accumulated damage using the toggle bar in the lower left (Figure 16). Remember, when the accumulated damage is equal to or greater than one, failure occurs.

 

 

Figure 16: Viewing ‘Cumulative Damage’ instead of ‘Cumulative Cycle Count’'Figure 16: Viewing ‘Cumulative Damage’ instead of ‘Cumulative Cycle Count’'

More Methods

 

There are several other methods for fatigue life calculation in LMS Tecware ProcessBuilder. There are methods for Stress Life and Strain Life calculations.

 

These other fatigue methods can be run via LMS Test.Lab tokens with LMS Test.Lab 16A revision or higher.

 

More Fatigue and Durability links: 

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