# 14.7.4. Plot stress distribution of plane stress quad model (ops_vis)ΒΆ

Example .py file 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 import openseespy.opensees as ops import openseespy.postprocessing.ops_vis as opsv # import opensees as ops # local compilation # import ops_vis as opsv # local import matplotlib.pyplot as plt ops.wipe() ops.model('basic', '-ndm', 2, '-ndf', 2) ops.node(1, 0., 0.) ops.node(2, 0., 1.) ops.node(3, 0., 2.) ops.node(4, 0., 3.) ops.node(5, 0., 4.) ops.node(6, 1., 0.) ops.node(7, 1., 1.) ops.node(8, 1., 2.) ops.node(9, 1., 3.) ops.node(10, 1., 4.) ops.node(11, 2., 0.) ops.node(12, 2., 1.) ops.node(13, 2., 2.) ops.node(14, 2., 3.) ops.node(15, 2., 4.) ops.node(16, 3., 0.) ops.node(17, 3., 1.) ops.node(18, 3., 2.) ops.node(19, 3., 3.) ops.node(20, 3., 4.) ops.node(21, 4., 0.) ops.node(22, 4., 1.) ops.node(23, 4., 2.) ops.node(24, 4., 3.) ops.node(25, 4., 4.) ops.nDMaterial('ElasticIsotropic', 1, 1000, 0.3) ops.element('quad', 1, 1, 6, 7, 2, 1, 'PlaneStress', 1) ops.element('quad', 2, 2, 7, 8, 3, 1, 'PlaneStress', 1) ops.element('quad', 3, 3, 8, 9, 4, 1, 'PlaneStress', 1) ops.element('quad', 4, 4, 9, 10, 5, 1, 'PlaneStress', 1) ops.element('quad', 5, 6, 11, 12, 7, 1, 'PlaneStress', 1) ops.element('quad', 6, 7, 12, 13, 8, 1, 'PlaneStress', 1) ops.element('quad', 7, 8, 13, 14, 9, 1, 'PlaneStress', 1) ops.element('quad', 8, 9, 14, 15, 10, 1, 'PlaneStress', 1) ops.element('quad', 9, 11, 16, 17, 12, 1, 'PlaneStress', 1) ops.element('quad', 10, 12, 17, 18, 13, 1, 'PlaneStress', 1) ops.element('quad', 11, 13, 18, 19, 14, 1, 'PlaneStress', 1) ops.element('quad', 12, 14, 19, 20, 15, 1, 'PlaneStress', 1) ops.element('quad', 13, 16, 21, 22, 17, 1, 'PlaneStress', 1) ops.element('quad', 14, 17, 22, 23, 18, 1, 'PlaneStress', 1) ops.element('quad', 15, 18, 23, 24, 19, 1, 'PlaneStress', 1) ops.element('quad', 16, 19, 24, 25, 20, 1, 'PlaneStress', 1) ops.fix(1, 1, 1) ops.fix(6, 1, 1) ops.fix(11, 1, 1) ops.fix(16, 1, 1) ops.fix(21, 1, 1) ops.equalDOF(2, 22, 1, 2) ops.equalDOF(3, 23, 1, 2) ops.equalDOF(4, 24, 1, 2) ops.equalDOF(5, 25, 1, 2) ops.timeSeries('Linear', 1) ops.pattern('Plain', 1, 1) ops.load(15, 0., -1.) ops.analysis('Static') ops.analyze(1) # - plot model plt.figure() opsv.plot_model() plt.axis('equal') # - plot deformation plt.figure() opsv.plot_defo() # opsv.plot_defo(sfac, unDefoFlag=1, fmt_undefo='g:') plt.axis('equal') # get values at OpenSees nodes sig_out = opsv.sig_out_per_node() print(f'sig_out:\n{sig_out}') # - visu stress map # !!! select from sig_out: e.g. vmises # j, jstr = 0, 'sxx' # j, jstr = 1, 'syy' # j, jstr = 2, 'sxy' j, jstr = 3, 'vmis' # j, jstr = 4, 's1' # j, jstr = 5, 's2' # j, jstr = 6, 'alfa' nds_val = sig_out[:, j] # print(f'nds_val:\n{nds_val}') plt.figure() opsv.plot_stress_2d(nds_val) plt.xlabel('x [m]') plt.ylabel('y [m]') plt.title(f'{jstr}') # plt.savefig(f'quads_4x4_{jstr}.png') # for educational purposes show values at integration points and # nodes which can finally be averaged at nodes eles_ips_crd, eles_nds_crd, nds_crd, quads_conn = opsv.quad_crds_node_to_ip() print(f'\neles_ips_crd:\n{eles_ips_crd}') print(f'\neles_nds_crd:\n{eles_nds_crd}') print(f'\nnds_crd:\n{nds_crd}') print(f'\nquads_conn:\n{quads_conn}') eles_ips_sig_out, eles_nds_sig_out = opsv.sig_out_per_ele_quad() print(f'\neles_ips_sig_out:\n{eles_ips_sig_out}') print(f'\neles_nds_sig_out:\n{eles_nds_sig_out}') sig_out_indx = j # same as j, jstr fig = plt.figure(figsize=(22./2.54, 18./2.54)) # centimeter to inch conversion fig.subplots_adjust(left=.08, bottom=.08, right=.985, top=.94) opsv.plot_mesh_with_ips_2d(nds_crd, eles_ips_crd, eles_nds_crd, quads_conn, eles_ips_sig_out, eles_nds_sig_out, sig_out_indx) plt.xlabel('x [m]') plt.ylabel('y [m]') # plt.savefig(f'quads_4x4_{jstr}_ips_nds_vals.png') plt.show() exit()