	Applies To
	Product(s):	AutoPIPE
	Version(s):	2004, XM, V8i, CONNECT;
	Area:	Calculations
	Original Author:	Bentley Technical Support Group
	Date Logged & Current Version	Nov. 2015 10.00.00.10

Problem:

The results from ASME NB Eq 12 + Eq. 13 stresses don’t equal Eq. 10, for a specific transient pair using AutoPIPE, why?

C3 is not used in this particular analysis, as you can see below, the discontinuity stress is zero. There is no difference between Eq. 10 and Eq. 12 + Eq. 13, except for how Autopupe decides to break apart the moment loading. Is it possible that something is being doubly accounted for in the moment term?

Answer:

There are small differences between the equations and doubtful that Eq12 + Eq13 would equal Eq10. The influence of the discontinuity part can be significant as the C'3 term is different to C3.

From the above screen shot of the results, no further comment is possible. Suggest to work through the equations and assign the correct moments and SIFs and see if it works out.

Furthermore, consider the equations and what is included in the assessment. If the discontinuity effect was ignored as suggested above this is what is happening according to the definitions in ASME:

Eqn 10 is a range or stress going from one load condition to another and does not contain Gravity loads but does contain all other mechanical loads SAM Earthquake etc.

Eqn 12 considers only the Thermal loads.

Eqn 13 takes the moment from Eqn 9 so includes Gravity and other mechanical loads

EQUATION 10	EQUATION 12	EQUATION 13 (taken from EQ 9)
SAM, RXX, TXX	TXX	GR, RXX, SAM (if included)

Again, Eqn 12 + Eq 13 does not equal Eqn 10.

It isn’t clear from one line of output what is happening here, but one can assume that Load Set pair 28-32 is between two thermal cases since Eqn 12 = Moment part of Eqn 10. Where a load pair involve mechanical load sets this won’t be the case. Depending on what loads are included in the load pair will determine how the values are calculated and how they relate.

Q. The results from ASME NB Eq 12 + Eq. 13 stresses don’t equal Eq. 10, for a specific transient pa

Problem:

Answer:

See Also