Applies To
	Product:	AutoPIPE
	First Affected Version:
	Found in Version:	12.02.00.10
	Fixed and Released in Version:	12.04
	Area:	Time history
	Severity:	Critical
	Backlog Issue Number:	1061807

Behavior

Problem Description

Time history load cases use Time History Profile (*.THP) files to read time/load data pairs during time history analysis. Even though time/load pair is comma separated in the time history profile file, program only reads the first ten characters (including blanks) for the time values of each time/load pair in the Time History Profile file. The trailing characters in excess of ten characters for time values are not read during analysis, which may result in incorrect time history results.

Time history profile files may contain more than 10 characters for time values ONLY in following conditions
1. User created THP file by hand with more than ten characters for time values.
2. For AutoPIPE v12.0.0 through AutoPIPE v12.3.0, the THP files generated by steam relief: steam relief writes 15 characters (including preceding blank spaces) for the time value of each time/load pair. The trailing 5 characters of time value are thus not read during analysis, which may result in incorrect time history results.

Time History Profiles files generated by the program (through Time History Profile dialog or Fluid Transient) mostly limits the time/load value significant digits to 10 characters only, and hence such files are not impacted by this defect.

Steps to repeat

To illustrate this defect, the following scenario can be considered:

Step 1: Create a new ASME B31.3 model with English units

Step 2: Define a new pipe identifier with the following data:

Pipe Identifier: PIP12
Nominal Diameter: 12.0 in
Schedule: STD
Material: A106-B

Step 3: Keep the default values for on the Operating Pressure & Temperature dialog that appears and press OK

Step 4: Insert an anchor at the first point in the model (A00)

Step 5: Invoke the Run Point dialog and enter the following data:

Generate Points: 5
Offset DX: 5.0 ft
This will generate 5 points in the model with last point as A05.

Step 6: Launch the Time History Profile dialog and create a new Time-Force profile named PROF01 using the following data pairs:

Time (sec) Force (lbf)
0.0 0.0
1.0 8000
2.0 8000
3.0 0.0

Step 7: Launch the Time History Location dialog and create a new Time History Location named LOC01 using the following data:

Point: A05
Select History: PROF01
Scale: 1.0
DX: 0.0
DY: 1.0
DZ: 0.0
Start: 0.0

Step 8: Launch the Dynamic Analysis dialog. Enable “Analyze up to Cutoff Frequency” checkbox on the Modal tab and set the Cut-off frequency (Hz) to 999 and press Apply.

Step 9: Go to the Time History tab and add a new Time History Load Case with the following data:

File 1: LOC01
Duration: 3.0 sec

Step 10: Press OK on the Dynamic Analysis and Analyze the model. Note that the analysis is completed without any warnings.

Step 11: Launch the Result Review dialog and click No on the Confirm dialog if it appears. Click on the Anchor tab. Note that the Global FY for Time History 1 load combination would be around 8,500 lbf (slight variations due to material data changes may occur)

Step 12: Go to the model directory and open PROF01.THP file. Update the number of blank spaces to 10 before the first non-blank character of time value for each of row 3 to 6. Save the file.

Step 13: Analyze the model again. Note that a warning message regarding the smallest timestep for the THP file will be displayed. This is because time history analysis is unable to read the time values from the Time History Profile file correctly.

Step 14: Launch the Result Review dialog, click No on the Confirm dialog if it appears. Click on the Anchor tab.

Note that the Global FY for Time History 1 load combination is now around 197 lbf, which is unconservative.

Evaluation Criteria

The following considerations are provided to assist in your evaluation of the potential impact of this defect on the results:

1. Evaluate whether this defect has affected any existing models by considering the criteria below:

a. Was the model created or updated in program version 11.2.0 or later?
b. Were there any Time History cases defined in the model?
c. Was there any Time History Profile associated with any of the Time History Cases with the time and/or load value having significant digits after the first 10 characters for any of the time/load pairs?

A 'No' to one or more of the above criteria means that this defect does not affect the model’s results. No further consideration for this model is necessary. Otherwise the following mitigation conditions can be considered:

Time History Profiles files generated by the Time History Profile dialog or Fluid Transient mostly limits the significant digits for time/load value to 10 characters only, and hence such files may not be impacted by this defect.

Time History Profile files automatically generated by Steam Relief for AutoPIPE v11.2 through AutoPIPE v11.4 mostly limits the time/load value to 10 characters, and hence such files may not be impacted by this defect.

Workaround

Manually update the Time History Profile files so that the significant digits for the time value are within the first 10 characters.

Solution

Program shall read all the characters entered for the time value for each time/load pair entered in the Time History Profile (*.THP) files.

Additionally, to assist in the screening of the models created in previous program versions for any potential impact by this defect, the program shall automatically examine the model database after opening the model and generate a report (model name + "_D1061807.TXT"), listing the Time History Load Cases potentially impacted by this defect. The program shall display the following confirmation message:

“Time History results may be incorrect due to a previous program defect #1061807. Would you like to review the evaluation report?”

The contents of the critical error evaluation report shall be like the following sample critical error report:

Defect #1061807 Evaluation Report

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

Model Name: TEST1
Model Version: 12.00.00.10
Program Version: 12.02.00.14
Report Filename: TEST1_D1061807.TXT

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

Time History results for load cases having significant digits for the time and/or load value spanning more than ten characters in the associated Time History Profile file(s) may be incorrect due to a previous program defect #1061807. Please refer to the published defect report for more details, mitigation conditions, and instructions. To assist in the screening of this model for any potential impact by this defect, program has examined the model database and has found that the results for the Time History load cases (with impacted profile files limited to first 100 file for each load case) listed below may be incorrect. Model should be re-analyzed using this program version.

After saving this model or running any analysis in this version or later commercial release versions, this screening will no longer be performed.

Time History load cases (profiles) potentially impacted by this defect:
-----------------------------------------------------------------------

Time History 3
W_F1.THP

Time History 4
W_F3.THP

Time History 5
W_D2.THP

Also See:

Critical and High issues released in v.12.04.

Known Issues in AutoPIPE (Enhancements, defects, etc..)

Bentley AutoPIPE