# 14.2.6. 2D Column - Dynamic EQ Ground MotionΒΆ

Converted to openseespy by: Pavan Chigullapally
University of Auckland
Email: pchi893@aucklanduni.ac.nz

1. EQ ground motion with gravity- uniform excitation of structure
2. All units are in kip, inch, second
3. Note: In this example, all input values for Example 1a are replaced by variables. The objective of this example is to demonstrate the use of variables in defining
4. The OpenSees input and also to run various tests and algorithms at once to increase the chances of convergence
5. To run EQ ground-motion analysis (BM68elc.acc needs to be downloaded into the same directory)
6. The detailed problem description can be found here (example:2a)
7. The source code is shown below, which can be downloaded here.
  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 # -*- coding: utf-8 -*- """ Created on Mon Apr 22 15:12:06 2019 @author: pchi893 """ # Converted to openseespy by: Pavan Chigullapally # University of Auckland # Email: pchi893@aucklanduni.ac.nz # EQ ground motion with gravity- uniform excitation of structure # all units are in kip, inch, second ##Note: In this example, all input values for Example 1a are replaced by variables. The objective of this example is to demonstrate the use of variables in defining #the OpenSees input and also to run various tests and algorithms at once to increase the chances of convergence # Example 2a. 2D cantilever column, dynamic eq ground motion #To run EQ ground-motion analysis (BM68elc.acc needs to be downloaded into the same directory) #the detailed problem description can be found here: http://opensees.berkeley.edu/wiki/index.php/Examples_Manual (example:2a) # -------------------------------------------------------------------------------------------------- # OpenSees (Tcl) code by: Silvia Mazzoni & Frank McKenna, 2006 # # ^Y # | # 2 __ # | | # | | # | | # (1) LCol # | | # | | # | | # =1= _|_ -------->X # # SET UP ---------------------------------------------------------------------------- import openseespy.opensees as op #import the os module import os import math op.wipe() ######################################################################################################################################################################### ######################################################################################################################################################################### op.model('basic', '-ndm', 2, '-ndf', 3) #to create a directory at specified path with name "Data" os.chdir('C:\\Opensees Python\\OpenseesPy examples') #this will create the directory with name 'Data' and will update it when we rerun the analysis, otherwise we have to keep deleting the old 'Data' Folder dir = "C:\\Opensees Python\\OpenseesPy examples\\Data-2a" if not os.path.exists(dir): os.makedirs(dir) #this will create just 'Data' folder #os.mkdir("Data") #detect the current working directory #path1 = os.getcwd() #print(path1) LCol = 432.0 # column length Weight = 2000.0 # superstructure weight # define section geometry HCol = 60.0 # Column Depth BCol = 60.0 # Column Width PCol =Weight # nodal dead-load weight per column g = 386.4 Mass = PCol/g ACol = HCol*BCol*1000 # cross-sectional area, make stiff IzCol = (BCol*math.pow(HCol,3))/12 # Column moment of inertia op.node(1, 0.0, 0.0) op.node(2, 0.0, LCol) op.fix(1, 1, 1, 1) op.mass(2, Mass, 1e-9, 0.0) ColTransfTag = 1 op.geomTransf('Linear', ColTransfTag) #A = 3600000000.0 #E = 4227.0 #Iz = 1080000.0 fc = -4.0 # CONCRETE Compressive Strength (+Tension, -Compression) Ec = 57*math.sqrt(-fc*1000) # Concrete Elastic Modulus (the term in sqr root needs to be in psi op.element('elasticBeamColumn', 1, 1, 2, ACol, Ec, IzCol, ColTransfTag) op.recorder('Node', '-file', 'Data-2a/DFree.out','-time', '-node', 2, '-dof', 1,2,3, 'disp') op.recorder('Node', '-file', 'Data-2a/DBase.out','-time', '-node', 1, '-dof', 1,2,3, 'disp') op.recorder('Node', '-file', 'Data-2a/RBase.out','-time', '-node', 1, '-dof', 1,2,3, 'reaction') #op.recorder('Drift', '-file', 'Data-2a/Drift.out','-time', '-node', 1, '-dof', 1,2,3, 'disp') op.recorder('Element', '-file', 'Data-2a/FCol.out','-time', '-ele', 1, 'globalForce') op.recorder('Element', '-file', 'Data-2a/DCol.out','-time', '-ele', 1, 'deformations') #defining gravity loads op.timeSeries('Linear', 1) op.pattern('Plain', 1, 1) op.load(2, 0.0, -PCol, 0.0) Tol = 1e-8 # convergence tolerance for test NstepGravity = 10 DGravity = 1/NstepGravity op.integrator('LoadControl', DGravity) # determine the next time step for an analysis op.numberer('Plain') # renumber dof's to minimize band-width (optimization), if you want to op.system('BandGeneral') # how to store and solve the system of equations in the analysis op.constraints('Plain') # how it handles boundary conditions op.test('NormDispIncr', Tol, 6) # determine if convergence has been achieved at the end of an iteration step op.algorithm('Newton') # use Newton's solution algorithm: updates tangent stiffness at every iteration op.analysis('Static') # define type of analysis static or transient op.analyze(NstepGravity) # apply gravity op.loadConst('-time', 0.0) #maintain constant gravity loads and reset time to zero #applying Dynamic Ground motion analysis GMdirection = 1 GMfile = 'BM68elc.acc' GMfact = 1.0 Lambda = op.eigen('-fullGenLapack', 1) # eigenvalue mode 1 import math Omega = math.pow(Lambda, 0.5) betaKcomm = 2 * (0.02/Omega) xDamp = 0.02 # 2% damping ratio alphaM = 0.0 # M-prop. damping; D = alphaM*M betaKcurr = 0.0 # K-proportional damping; +beatKcurr*KCurrent betaKinit = 0.0 # initial-stiffness proportional damping +beatKinit*Kini op.rayleigh(alphaM,betaKcurr, betaKinit, betaKcomm) # RAYLEIGH damping # Uniform EXCITATION: acceleration input IDloadTag = 400 # load tag dt = 0.01 # time step for input ground motion GMfatt = 1.0 # data in input file is in g Unifts -- ACCELERATION TH maxNumIter = 10 op.timeSeries('Path', 2, '-dt', dt, '-filePath', GMfile, '-factor', GMfact) op.pattern('UniformExcitation', IDloadTag, GMdirection, '-accel', 2) op.wipeAnalysis() op.constraints('Transformation') op.numberer('Plain') op.system('BandGeneral') op.test('EnergyIncr', Tol, maxNumIter) op.algorithm('ModifiedNewton') NewmarkGamma = 0.5 NewmarkBeta = 0.25 op.integrator('Newmark', NewmarkGamma, NewmarkBeta) op.analysis('Transient') DtAnalysis = 0.01 TmaxAnalysis = 10.0 Nsteps = int(TmaxAnalysis/ DtAnalysis) ok = op.analyze(Nsteps, DtAnalysis) tCurrent = op.getTime() # for gravity analysis, load control is fine, 0.1 is the load factor increment (http://opensees.berkeley.edu/wiki/index.php/Load_Control) test = {1:'NormDispIncr', 2: 'RelativeEnergyIncr', 4: 'RelativeNormUnbalance',5: 'RelativeNormDispIncr', 6: 'NormUnbalance'} algorithm = {1:'KrylovNewton', 2: 'SecantNewton' , 4: 'RaphsonNewton',5: 'PeriodicNewton', 6: 'BFGS', 7: 'Broyden', 8: 'NewtonLineSearch'} for i in test: for j in algorithm: if ok != 0: if j < 4: op.algorithm(algorithm[j], '-initial') else: op.algorithm(algorithm[j]) op.test(test[i], Tol, 1000) ok = op.analyze(Nsteps, DtAnalysis) print(test[i], algorithm[j], ok) if ok == 0: break else: continue u2 = op.nodeDisp(2, 1) print("u2 = ", u2) op.wipe()