Cold Drawn Tube. Problem:

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Suzan Lewis
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1 Cold Dawn Tube Poblem: An AISI 1 cold-dawn steel tube has an ID of 1.5 in and an OD of 1.75 in. What maximum extenal pessue can this tube take if the lagest pincipal nomal stess is not to exceed 8 pecent of the minimum yield stength of the mateial? Joseph Shigley and Chales Mischke. Mechanical Engineeing Design 5th ed. New Yok: McGaw Hill, May.

2 Cold Dawn Tube Oveview Anticipated time to complete this tutoial: 3 minutes Tutoial Oveview This tutoial is divided into six pats: 1) Tutoial Basics ) Poblem Planning 3) Pepocessing 4) Solution 5) Post-Pocessing 6) Hand Calculations Audience This tutoial assumes an intemediate knowledge of ANSYS 8.; theefoe, it goes into modeate detail to explain each step. A poblem planning section has been added to help set up the poblem. Moe advanced ANSYS 8. uses should be able to complete this tutoial faily quickly. Peequisites 1) ANSYS 8. in house Stuctual Tutoial ) Completion of thee o moe Basic Machine Design Tutoials, including the Basic Pessue Vessel Tutoial. Objectives 1) Constuct a plan fo solving the poblem ) Build and solve Ansys models 3) Use a log file to iteatively solve the poblem Outcomes 1) Lean how to set up the poblem befoe stating Ansys ) Incease familiaity with the gaphical use inteface (GUI) 3) Lean how to ceate and mesh moe complex geometies 4) Incease familiaity with post pocessing tools

In this tutoial: Instuctions appea on the left. Visual aids coesponding to the text appea on the ight. Cold Dawn Tube Tutoial Basics All commands on the toolbas ae labeled.

3 In this tutoial: Instuctions appea on the left. Visual aids coesponding to the text appea on the ight. Cold Dawn Tube Tutoial Basics All commands on the toolbas ae labeled. Howeve, only opeations applicable to the tutoial ae explained. The instuctions should be used as follows: Bold > Example: Italics MB1 MB MB3 Text in bold ae buttons, options, o selections that the use needs to click on > Pepocesso > Element Type > Add/Edit/DeleteFile would mean to follow the options as shown to the ight to get you to the Element Types window Text in italics ae hints and notes Click on the left mouse button Click on the middle mouse button Click on the ight mouse button Some basic ANSYS functions ae: To otate the models use Ctl and MB3. To zoom use Ctl and MB and move the mouse up and down. To tanslate the models use Ctl and MB1. 3

4 Take a few minutes to plan out you solution to this poblem. You plan should include some of the following items: Cold Dawn Tube Poblem Planning 1) Obtain all necessay known infomation. Inside Diamete: Outside Diamete:.8*Sy: E fo 1 CD steel: Poisson's Ratio: ) Plan a simple, epesentative geomety. The entie tube does not need to be modeled. A quate of the coss section will suffice. The Ceate Patial Cylinde volume modeling tool is a good tool to ceate the geomety. If you model the geomety in the fist quadant, the bottom face can be constained in Y and the left face can be constained in X. The font face can be constained in Z. 3) Contemplate an appopiate element fo the mesh. 4) Detemine the best way to apply the pessue load to the exteio of the tube. Since the pessue to be applied to the exteio of the tube is unknown (the only specification is that it does not cause any pincipal nomal stess in the cylinde to exceed.8*sy), set up a paamete, P, to hold the value fo the pessue. 5) Identify which esults will be analyzed. Nodal pincipal stess solutions will be analyzed afte the solution is obtained. 6) Wite a log file and un iteative solutions. Using a log file will allow you to iteatively change the value of P until a maximum pincipal stess equals.8*sy. Since you ae ceating a solid model fom a volume, use an element listed unde the Solid categoy (possibly use Solid187). Choose an appopiate edge mesh size so thee ae at least two elements though the thickness of the patial cylinde. 4

5 1) Change the woking diectoy, jobname, and title of you poject. ) Set Pefeences to Stuctual. 3) Add a Solid187 element. 4) Ceate a Mateial Model. E: 3e6 PRXY:.3 5) Ceate a Patial Cylinde Volume. WP X: WP Y: Rad-1: 1.5 Theta-1: Rad-: 1.75 Theta-: 9 Depth: 1 Cold Dawn Tube Pepocessing You model should look simila to the pictue shown to the ight: 6) Change the Element Edge Length to.15. > Pepocesso > Meshing > Size Cntls > Manual Size > Global > Size 7) Mesh the volume (use fee meshed volume command). You model should look simila to the pictue shown to the ight: 5

6 Cold Dawn Tube Pepocessing 8) Apply Stuctual Displacement Constaints to the bottom, left, and font and back faces of the geomety. The bottom suface should be esticted fom moving in the Y diection. The left suface should be constained fom moving in X and the font and back sufaces should be constained fom moving in Z. 9) Ceate a paamete, P, and set the value to 75. 1) Apply Stuctual Pessue with magnitude P, to the exteio suface of the tube. You model should look simila to the pictue shown to the ight: 6

7 The model is eady to solve. 11) > Solution > Solve > Cuent LS Cold Dawn Tube Solution The model should take less than a minute to solve, but note that the time will vay depending on the compute. 7

8 1) Plot the nodal esults. > Geneal Postpoc > Plot Results > Contou Plot > Nodal Solution > Stess > 3d Pincipal Cold Dawn Tube Post Pocessing You model should look simila to the pictue shown to the ight: 13) Ceate a soted list of nodes with the maximum pinciple stesses. Tun absolute values on fo the sot. Sot in descending ode of the 3d Pincipal Stess. Include only the top 1 nodes in the list. The soted list should appea. Note that fo P = 75 the maximum pincipal stess value is -3,661 psi. 8

9 Cold Dawn Tube Post Pocessing 14) Wite a DB Log File with essential commands only. The log file should appea simila to the one shown to the ight. Remove lines shown in ed and add lines shown in blue to the appopiate places. Save the log file afte the appopiate changes ae made. Note: Ansys saves the log files with a file extension.lgw. If the compute pompts you to pick a pogam to use to open this file, choose Notepad. 15) Based on the maximum pincipal stess fom the solution that you just obtained, change the value of P in the log file to a new, easonable value. Copy all the text in the log file to the clipboad. In ANSYS select > File > Clea and Stat New 16) Paste the contents of the clipboad into the command line and hit ente. ANSYS will execute the commands of the log file. When the solution is finished, the soted nodes window should appea. Continue the iteative pocess until you find P such that the maximum pincipal stess does not exceed.8*sy. /BATCH /input,menust,tmp,'',,,,,,,,,,,,,,,,1 WPSTYLE,,,,,,,, /CWD,'J:\goups\pace\ANSYS Machine Design\Guided\Tutoial 14 Guided -Cold Dawn Tube; Pinicpal Stess\Results' /FILNAME,Cold Dawn Tube, /TITLE,Cold Dawn Tube /NOPR /PMETH,OFF, KEYW,PR_SET,1 KEYW,PR_STRUC,1 KEYW,PR_THERM, KEYW,PR_FLUID, KEYW,PR_ELMAG, KEYW,MAGNOD, KEYW,MAGEDG, KEYW,MAGHFE, KEYW,MAGELC, KEYW,PR_MULTI, KEYW,PR_CFD, /GO /PREP7 ET,1,SOLID187 MPTEMP,,,,,,,, MPTEMP,1, MPDATA,EX,1,,3e6 MPDATA,PRXY,1,,.3 CYL4,,,1.5,,1.75,9,1 ESIZE,.15,, MSHKEY, MSHAPE,1,3d CM,_Y,VOLU VSEL,,,, 1 CM,_Y1,VOLU CHKMSH,'VOLU' CMSEL,S,_Y VMESH,_Y1 CMDELE,_Y CMDELE,_Y1 CMDELE,_Y FINISH /SOL FLST,,1,5,ORDE,1 FITEM,,5 /GO DA,P51X,UY, FLST,,1,5,ORDE,1 FITEM,,6 /GO DA,P51X,UX, FLST,,1,5,ORDE,1 FITEM,, /GO DA,P51X,UZ, *SET,P, 75 FLST,,1,5,ORDE,1 FITEM,,3 /GO SFA,P51X,1,PRES,P SOLVE FINISH /POST1 AVPRIN,,, PLNSOL,S,3,,1 NSORT,S,3,,1,1, PRNSOL,S,PRIN 9

10 Cold Dawn Tube Hand Calculations 1 psi P Sy P theefoe P i i t i 11,167 ) )(.8 ( ,max = = = = = σ

Statically Indeterminate Beam

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