Applies To Product(s): AutoPIPE, Version(s): 2004, XM, & V8i Environment: N/A Area: Modeling Subarea: Original Author: Bentley Technical Support Group Attention: Please see the following AutoPIPE help section: Help Contents Contents Tab Modeling Approaches Modeling Approaches This help has been provided in order to give users ideas for modeling typical piping arrangements. The steps shown in each example should not be taken as the only method available to create models. In addition, the intent of the examples is to present ways to create adequate models of specific piping components for analytically purposes. Anchors Bends Cuts Flexible Joints Frames Hangers Nozzles Pipes Reducers Rotating Equipment Supports Tees Valves Vessels Comments, Questions, and Answer: Q1. Modeling an Elbow with Tapered weld joint for Nuclear NB analysis Answer: Model elbow as described above, at each end of the elbow where the elbow is welded to the pipe, Insert Xtra Data joint Type and User SIF there are multiple "Joint Type" available As-Welded Butt Weld Flush Butt Weld As-Welded Butt Weld NB 4250 Transition Flush Butt Weld NB 4250 Transition As-Welded Butt Weld 1:3 Transition Flush Butt Weld 1:3 Transition Socket/Fillet Weld Select the type of weld joint the best fits your requirements based on code description. In AutoPIPE, press toolbar icon "Show Joint Type", located on left toolbar near the bottom. Use this feature to clearly see where joint types have been applied, and review the "Joint Type, SIF" tab of the input grid for settings. Q2. Modeling 3D, 5D or Larger Sweep Elbows Answer : AutoPIPE's Bend Point dialog screen has a Bend radius field which defaults to Long radius with pull down option for short radius. You can either select short radius or, for a larger sweep elbow, click once on the Bend radius field and type the actual radius (units are in bottom right hand corner of screen). Q3. Inserting Valves, Reducers Or Other Components After Elbow Or After Tee Answer: A bend component is made up of 4 node points: A. Near Point - automatically generated B. Tagent Interface Point (TIP) - user generated C. Far Point - automatically generated D. Mid Point (if enabled) - user specified between Near and Far Point. AutoPIPE does not allow users to insert the next node point or component between the Bend's Near and Far points. If done, the bend cannot be drawn and a error message ( E732-3: Not enough clearance to fit bend xxx ) will be mentioned in the Tools Model Consistency check report. Solution, the user must first enter a pipe run directly after an elbow whose length is just beyond the automatically generated Near OR Far points before adding the next piping component. This means that there will be 2 points, a bend point and a run point, very close to one another. The should not be exactly in the same location, or another warning will be displayed about a zero length run ( W726-6: Near zero length element at point XXX ) The same technique is used for inserting valves and other components directly after a tee, AutoPIPE requires that the user first input a run of pipe after the tee before inserting the component to model the leg / branch weld points of the tee. AutoPPE will adjust the elbow's stiffness if it detects a flange or valve component within a defined distance from an elbow, see the next item below for more details: "Q4. When a flanged elbow is modeled in AutoPIPE, does it affect the stiffness of the elbow in the analysis? If so, how?" Q4. When a flanged or valve is modeled after an elbow in AutoPIPE, does it affect the stiffness of the elbow in the analysis? If so, how? Answer: Yes the stiffness of an elbow is affected if the program detects a flange or valve component within a certain distance after and elbow. In AutoPIPE, p lease see the following help section for details on this distance: Help Contents Contents Tab Command Reference Tools & Utility Commands Model Options Model Edit Options Distance L/D from flange/valve to bend. T he effect of this setting on the flexibility factor can be seen in the Tools Model Input Listing Elbow Report. AutoPIPE's official training class covers this modeling approach and model option setting. Q4. I have a question regarding 1000m radius bend in Autopipe. I would like to add points on the bend. What is the easiest way as I have to insert points at 6m intervals. Answer: There is no command in AutoPIPE to split/insert a bend with multiple points. However, please see the following options available based on the version of AutoPIPE being used. AutoPIPE V8i 09.05.xx.xx and Lower: Option #1: Create a miter bend with as many cuts as desired. Please see the following AutoPIPE help section for details: Help Contents Contents Tab Modeling Approaches Modeling Approaches Bend Miter Bends Model 2: 3 Cuts - Widely Spaced. Using Excel, calculate all Option #2: Create the bend in AutoCAD and manually transfer each node point (DX, DY, DZ) coordinates to AutoPIPE as new bends are added. AutoPIPE V8i 09.06.xx.xx and higher: Option #1: All options available in AutoPIPE 9.5 and lower Option #2: Create the bend in AutoCAD and import file using the new Import AutoCAD file procedure. Option #3: (Preferred method) Create a ring main using the new Ring Main Wizard, after the ring main has been created, cut/copy/paste/move it to the correct location in the model Q5 How does AutoPIPE calculate the weight of a typical pipe fittings (i.e. Tee, elbow, reducer, etc..)? Answer: AutoPIPE fittings are made up of equivalent center-line length of straight pipe with assigned pipe properties. Change the pipe properties used to construct a fitting in order to account for different fitting weights. Reducer are the only exception, (from online help): Over the length of the reducer, AutoPIPE assumes an average of the connecting pipes for the outside diameter (Do), wall thickness (t). This affects the reducer weight, pipe contents weight, and section properties. Material properties (E, a, and allowable stresses) from the pipe at the near end of the reducer are extended to the far end of the reducer. Q6. How to model a Pulled Bend and a does the program consider the thinning wall on the outer radius of a pulled bend? Answer: A pulled bend is a bend that is formed by a machine wrapping the pipe around a shoe horn form (i.e. like a tubing bender bending tubing) Using AutoPIPE Nuclear version, with piping codes ASME NB, NC, or ND selected, users can set Bend Type = Pulled. For other version of AutoPIPE, Standard or Plus (Advanced), using non-nuclear piping codes, to model a pulled bend, select Bend Type = "elbow", SIF and flexibility factor will automatically be calculated but suggest that bourdon pressure effect be turned on (Tools Model Options Edit "Include Bourdon rotational effect" check ON). One side effect of bending the work-piece is the wall thickness changes; the wall along the inner radius of the tube becomes thicker and the outer wall (extrafit) becomes thinner. AutoPIPE does not consider the different wall thickness. The wall thickness is a uniform value specified on the pipe properties dialog screen. Q7. My piping system has a section of bent piping (not mitered). The radius of the bend is approximately 6ft. The angle of the bend is about 120 degrees. How would I model this bend in AutoPIPE? Answer : See the following options: Option #1: see the following AutoPIPE help section: Help Contents Contents Tab Modeling Approaches Modeling Approaches Bend Miter Bends Model 2: 3 Cuts - Widely Spaced, use the math formulas to layout the piping and insert the bends points s needed Option #2: Construct the pipe layout to locate the intersect point of both piping runs connected to the bend (image below, BR02). After the straight pipe is layed out use Modify Convert Point to.. Bend command, specify 6' diameter bend radius and AutoPIPE will automatically insert the bend correctly. Option #3: In AutoPIPE 09.06.xx.xx and higher, use the ring main wizard, the ring is made CCW from the point, so create as a new segment and attach it after the ring has been made. OR, as the same segment careful to locate the ring center offset see following: Results: Q8. Can the software analyze stress in pipelines where the pipe turns that are not standard 45 or 90 degree turns? Answer : Yes, there are typically 2 types of bends in AutoPIPE: a. Normal bend (any sized fillet radius between two intersecting pipe lengths). b. Mitered bends (both closed and Wide) Note : 1. AutoPIPE assumes the bend is constructed without any kinks and has a uniform wall thickness per the PipeID specified. 2. Any bend angle the is modeled out side of the applied Piping code will need to have a user calculated SIF applied to the bend points as needed. 3. The image on the left is acceptable bend but the bend on the right, although can be constructed, is not good modeling practice. Recommend creating a mitered bend. Q9. How to model a socket elbow, or other Socket welded fittings (i.e. Tee, valves, Sockolet, etc..)? Answer : Apply manufacture recommended SIF values or refer to a specific piping code for recommended SIF values to be applied (note: the intent on many ASME codes to use conservatively an SIF value = 2.1) ASME Codes state the following regarding socket welds: B31.1 use 1.3 for socket welds with no undercut, and 2.1 for all others. B31.3 states "2.1 Max or 2.1 T/Cx but not less than 1.3. Cx is the fillet weld leg length" B31.8 states "2.1 Max or 2.1 T/Cx but not less than 1.3. " To apply this SIF to all bends and Tees perform the following: Press Select Bends to highlight all bends in the model, Press Select Tees to highlight all tee in the model Press Insert Xtra data Joint Type and User SIF select "Joint End Type" = "Socket or Fillet Weld " / "Socket or Fillet Weld (no undercut), OR, "Joint End Type" = User Manually enter the "Inplane SIF" = (manufacture / code recommended value, ex. 2.1) Manually enter the "Outplane SIF" = (manufacture / code recommended value, ex. 2.1) "Override all other SIFs at this point" = unchecked (i.e maximum SIF used if automatic SIF 2.1), "Flexibility Factor" = 1.0 (no flexibility) Press OK button to apply SIF values to all highlight components. To account for the extra weight of a 2000# to 9000# fitting: Create a new pipe property with the correct wall thickness Press Select Bends to highlight all bends in the model, Press Select Tees to highlight all tee in the model, Press Modify "Pipe Properties over range", select the new pipe property ID, and press OK button to assign the new pipe ID to the selected components. Q10. When defining an elbow, only specifying end points Elbows have fittings How to specify user stress indices to apply to only one end? Answer : With a nuclear piping code selected (i.e. ASME NB, NC, or ND, etc..), select the bend near or far point then select Insert Xtra Data Joint Type and User SIF select the proper joint type or select User to enter all the indices values. press OK button when completed. Press the SIF icon to show where SIF values are located: Q11. After inserting Xtra Data Joint Type & User SIF change to User Defined, and set the values for both in / out of plane SIF = 1.23 with Override all other SIF at this point checked on, the Bend data listing shows the code calculated value instead of my user SIF value at node point A01 F, why? Answer: This is by design, Bend data listing will show the code calculated SIF values. However, if a different SIF value was applied to a bend, the letter "u" is added directly after the value. As indicated at the bottom of the report, u = User sif present at the point, check user-SIF data listing. In addition, reviewing the code compliance report shows: See Also Bentley AutoPIPE External Links Bentley Technical Support KnowledgeBase Bentley LEARN Server Comments or Corrections? Bentley's Technical Support Group requests that you please submit any comments you have on this Wiki article to the "Comments" area below. THANK YOU!
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