	Applies To
	Product:	AutoPIPE
	First Affected Version:	6
	Found in Version:	09.06.00.15
	Fixed and Released in Version:	09.06.00.19
	Area:	All
	Severity:	Critical
	Backlog Issue Number:	139135

Problem Description

If the hot modulus value for a particular thermal case changes between points laying on the same pipe ID, the hot modulus value for the first point may be used for all subsequent points. This is only true when such a temperature case is selected as hot modulus case for an analysis set. The analysis results such as displacement, forces & moments, and reactions etc. for load cases in such an analysis set may be incorrect.

Using hot modulus for analysis is mandatory for ASME NB code. For ASME B31.3 code, hot modulus usage is mandated if change in elastic modulus significantly affect the stress distribution. For JSME code, using hot modulus is mandatory for seismic analysis. For B31.1, ASME NC, and ASME ND codes, using hot modulus for analysis is not mandatory by the code.

To illustrate this problem the following scenario can be considered:

Step 1: Open ‘B313_APPENDIXS_EXAMPLE1.DAT’ sample model
Step 2: Delete the V-stop at node 20
Step 3: Open Analysis Sets dialog (Load > Static Analysis Sets) and select T1 as hot modulus case
Step 4: Analyze the model and generate Displacements report and note the Displacement value at node 20 in the Y direction for Gravity load combination (-3.596 in)
Step 5: Now update the temperature values for temperature case T1 for nodes 15 & 20 to 700 deg F. Note that the corresponding hot modulus values are updated
Step 6: Analyze the model once again and take out the Displacement report

Note that the displacement value at node 20 in the Y direction for Gravity load combination remains the same (-3.596 in).

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 in program version 6.00 or later?
b. Was there any analysis set with Hot Modulus set to a value other than "None"?
c. The following two conditions are met:

i. Was there a pipe having the same Pipe ID and with points having different hot modulus values for a temperature case?
AND
ii. Was the same temperature case used as hot modulus case for any of the analysis sets?

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.

2. Otherwise, the following mitigation conditions should be considered:

a. If the hot modulus change is across certain components like Reducers, Valves, Flexible Joints then the correct hot modulus value will be used
b. If the hot modulus change is across a pipe section with rigid properties applied on it then the correct hot modulus values will be used
c. If the hot modulus change is at a point where the pipe segment changes then the correct hot modulus values will be used

Solution

When evaluating hot modulus for a component, always use the correct hot modulus value for the member.

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 + "_D11153.TXT") listing the Analysis Sets that may be effected by this defect. The program will display the following confirmation message:
One or more analysis results may be affected by a previous program defect in which different hot modulus value are not used for points on the same pipe ID. Would you like to review the evaluation report?

Avoidance

1. Update the pipe ID at the location of hot modulus change to a new pipe ID with the same pipe properties
2. Start a new segment at the location of hot modulus change

AutoPIPE known issue - defect 139135 (11153)

Problem Description

Solution

Avoidance

See Also