NonLinear Tutorial - PDF document

NonLinear Tutorial Buckling loads are critical loads where table. Each load has an associated 1.Eigenvaluetabulated solutions. However, in real-life, structurrities prevent most real-2.Nonlinear it employs non-linear, large-deflection, static analysis to predict buckli g mode. Universi y of Alberta AN www.mece.ualberta.ca/tutorials/an y s/IT/Buckli g /Buckli g .html Co py ri g ht © 2003 Universit y of Alberta Preprocessing: Defining the Problem1.Open preprocessor menu2.Give example a Title/title,Eigen-Value Buckling Analysis3.Define Keypoints4.Create Lines Keypoints Coordinates (x,y) 1 (0,0) 2 (0,100) Universi y of Alberta AN www.mece.ualberta.ca/tutorials/an y s/IT/Buckli g /Buckli g .html Co py ri g ht © 2003 Universit y of Alberta �Preprocessor �� Modeling Create 5.Define the Type of Element will use the BEAM3 (Beam 2D elastic) el f 6.Define Real Constantsi.Cross-sectional ii.Area moment of inertia IZZ: 833.333 iii.Total Beam Height HEIGHT: 10 7.Define Element Material Propertiesi.Young's modulus EX: 200000 ii.Poisson's Ratio PRXY: 0.3 8.Define Mesh Size9.Mesh the frame1.Define Analysis Type2.Activate prestress effectsYou must first ensure that y ou are lookin g at the unabrid g ed solution menu so that y ou can select Universi y of Alberta AN www.mece.ualberta.ca/tutorials/an y s/IT/Buckli g /Buckli g .html Co py ri g ht © 2003 Universit y of Alberta ES] item to 'Prestress ON', which ensures the stress stiffness matrix is calculated. This 3.Apply Constraints4.Apply LoadsThe eignenvalue solver uses a unit force to determine the necessary buckling load. Applying a load pp l y a vertical ( FY ) p oint load of -1 N to the to p of the beam ( ke yp oint 2 ) . Universi y of Alberta AN www.mece.ualberta.ca/tutorials/an y s/IT/Buckli g /Buckli g .html Co py ri g ht © 2003 Universit y of Alberta 5.Solve the System�Solution Solv�e Current LS 6.Exit the Solution processor to close the solution menu and re-7.Define Analysis Type8.Specify Buckling Analysis Optionsmethod ma y not be ade q uate and the Subs p ace method would have to be used. Universi y of Alberta AN www.mece.ualberta.ca/tutorials/an y s/IT/Buckli g /Buckli g .html Co py ri g ht © 2003 Universit y of Alberta 9.Solve the System�Solution Solv�e Current LS 10.Exit the Solution processor11.Expand the solution��ass Single Expand Expand Modes ... Universi y of Alberta AN www.mece.ualberta.ca/tutorials/an y s/IT/Buckli g /Buckli g .html Co py ri g ht © 2003 Universit y of Alberta 12.Solve the System�Solution Solv�e Current LS General Po�stproc List Results � Detailed SummaryGeneral Post��proc Plot Results Deformed ShapeCommand File Mo interface that you may want to browse. Open the file and save it to your computer. Now go to �'File Read input from...' and select the file. Universi y of Alberta AN www.mece.ualberta.ca/tutorials/an y s/IT/Buckli g /Buckli g .html Co py ri g ht © 2003 Universit y of Alberta NonLinear Tutorial Preprocessing: Defining the Problem1.Open preprocessor menu2.Give example a Title/TITLE, Nonlinear Buckling Analysis3.Create Keypoints4.Define Lines�Preprocessor �� Modeling Create 5.Define Element Types will use the BEAM3 (Beam 2D elastic) el f 6.Define Real Constantsi.Cross-sectional ii.Area Moment of Inertia IZZ: 833.333 iii.Total beam height HEIGHT: 10 7.Define Element Material Pro p erties Keypoint Coordinates (x,y) 1 (0,0) 2 (0,100) Universi y of Alberta AN www.mece.ualberta.ca/tutorials/an y s/IT/Buckli g /Buckli g .html Co py ri g ht © 2003 Universit y of Alberta i.Young's modulus EX: 200e3 ii.Poisson's Ratio PRXY: 0.3 8.Define Mesh Size9.Mesh the frame1.Define Analysis Type2.Set Solution ControlsEnsure the followin g selections are made under the 'Basic' tab ( as shown above ) Universi y of Alberta AN www.mece.ualberta.ca/tutorials/an y s/IT/Buckli g /Buckli g .html Co py ri g ht © 2003 Universit y of Alberta A.Ensure Large Static Displacements are permithe effects of large B.Ensure Automatic time stepping is on. AutomatiDecreasing the step size usually ensures better tic Time Step feature will determine an C.Enter 20 as the number of substeps. This will set the initial substep to 1/20 D.Enter a maximum number of substeps of 1000. E.Enter a minimum number of substeps of 1. F.Ensure all solution items are writen to a results file. A.Ensure Line Search is 'On'. This option is usB.Ensure Maximum Number of Universi y of Alberta AN www.mece.ualberta.ca/tutorials/an y s/IT/Buckli g /Buckli g .html Co py ri g ht © 2003 Universit y of Alberta 3.Apply Constraints4.Apply Loads5.Solve the System�Solution Solv�e Current LS g will a pp ear on y our screen for NonLinear Anal y ses Universi y of Alberta AN www.mece.ualberta.ca/tutorials/an y s/IT/Buckli g /Buckli g .html Co py ri g ht © 2003 Universit y of Alberta 1.View the deformed shape�Utility Menu PlotCt�rls p la y of element' ON ( as shown below ) . Universi y of Alberta AN www.mece.ualberta.ca/tutorials/an y s/IT/Buckli g /Buckli g .html Co py ri g ht © 2003 Universit y of Alberta ��General Postproc Plot Results �Deformed Shape... Def + undeformed PLDISP,1 Universi y of Alberta AN www.mece.ualberta.ca/tutorials/an y s/IT/Buckli g /Buckli g .html Co py ri g ht © 2003 Universit y of Alberta View the deflection contour plot y Post p rocessin g : Viewin g the Results Universi y of Alberta AN www.mece.ualberta.ca/tutorials/an y s/IT/Buckli g /Buckli g .html Co py ri g ht © 2003 Universit y of Alberta 1.Define Variables�Main Menu TimeHist PostproClick the add button in the upper left co� Y-Component of displacement Universi y of Alberta AN www.mece.ualberta.ca/tutorials/an y s/IT/Buckli g /Buckli g .html Co py ri g ht © 2003 Universit y of Alberta Reaction Forces� Structural 2.Graph Results over Time g ra p hin g button in the Time Histor y Variables window. Universi y of Alberta AN www.mece.ualberta.ca/tutorials/an y s/IT/Buckli g /Buckli g .html Co py ri g ht © 2003 Universit y of Alberta red due to a small increase in force. This is slightly less than Command File Mo interface that you may want to browse. Open the file and save it to your computer. Now go to �'File Read in p ut from...' and select the file. Universi y of Alberta AN www.mece.ualberta.ca/tutorials/an y s/IT/Buckli g /Buckli g .html Co py ri g ht © 2003 Universit y of Alberta