Cantilever 2D Column with Units- Dynamic EQ Ground Motion

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

1. To run Uniaxial Inelastic Material, Fiber Section, Nonlinear Mode, Uniform Earthquake Excitation

2. First import the InelasticFiberSection.py (upto gravity loading is already in this script) and run the current script

3. To run EQ ground-motion analysis BM68elc.acc needs to be downloaded into the same directory)

4. Same acceleration input at all nodes restrained in specified direction (uniform acceleration input at all support nodes)

5. The problem description can be found here (example:3)

6. The source code is shown below, which can be downloaded here.

# -*- 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 
# Example 3. 2D Cantilever -- EQ ground motion
#To run Uniaxial Inelastic Material, Fiber Section, Nonlinear Mode, Uniform Earthquake Excitation:First import the InelasticFiberSection.py(upto gravity loading is already in this script)
#and run the current script
#To run EQ ground-motion analysis (BM68elc.acc needs to be downloaded into the same directory)
# Same acceleration input at all nodes restrained in specified direction (uniform acceleration input at all support nodes)
#the detailed problem description can be found here: http://opensees.berkeley.edu/wiki/index.php/Examples_Manual  (example: 3)
# --------------------------------------------------------------------------------------------------
#	OpenSees (Tcl) code by:	Silvia Mazzoni & Frank McKenna, 2006
##########################################################################################################################################################################
import openseespy.opensees as op
#import the os module
#import os
import math
op.wipe()
#########################################################################################################################################################################
import InelasticFiberSection
#applying Dynamic Ground motion analysis
Tol = 1e-8
GMdirection = 1
GMfile = 'BM68elc.acc'
GMfact = 1.0
Lambda = op.eigen('-fullGenLapack', 1) # eigenvalue mode 1
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 # time-step Dt for lateral analysis
TmaxAnalysis = 10.0 # maximum duration of ground-motion analysis

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()