"""OpenSees Example 2a. Elastic Cantilever Column with variables. OpenSees Wiki: https://opensees.berkeley.edu/wiki/index.php?title=OpenSees_Example_2a._Elastic_Cantilever_Column_with_variables This example mirrors the Tcl tutorial's teaching goal: the model is defined from a small set of named parameters, then derived quantities such as mass, section area, and stiffness are computed from them. The resulting OTKO project contains: - gravity preload - static pushover - earthquake base excitation with ``BM68elc.acc`` Run from the repository root: python examples/ex2a_canti2d_elastic_element.py Produces ``examples/ex2a_canti2d_elastic_element.osmodel``. """ from __future__ import annotations from pathlib import Path import math import sys if __package__ is None or __package__ == "": sys.path.insert(0, str(Path(__file__).resolve().parents[1] / "src")) from otko.core import ( # noqa: E402 ElasticBeamColumn, ElasticSection, LinearTimeSeries, NodalLoad, Node, PathTimeSeries, PlainLoadPattern, Project, ProjectMeta, PushoverCase, StaticCase, TransientCase, UniformExcitationPattern, UnitSystem, ) from otko.services import load_project, save_project # noqa: E402 from otko.services.peer_record import parse_plain_values # noqa: E402 # Geometry and loading variables from the Tcl tutorial. L_COL = 432.0 WEIGHT = 2000.0 H_COL = 60.0 B_COL = 60.0 G_ACCEL = 386.4 FC = -4.0 # Derived properties. P_COL = WEIGHT MASS = P_COL / G_ACCEL A_COL = B_COL * H_COL * 1000.0 IZ_COL = (1.0 / 12.0) * B_COL * H_COL**3 E_C = 57.0 * math.sqrt(-FC * 1000.0) # Analysis variables. N_GRAVITY = 10 GRAVITY_STEP = 1.0 / N_GRAVITY PUSH_TARGET = 0.01 * L_COL PUSH_STEP = 0.001 * L_COL H_LOAD = WEIGHT GROUND_DT = 0.01 GROUND_FACTOR = 1.0 ANALYSIS_DT = 0.01 ANALYSIS_STEPS = 1000 DAMPING_RATIO = 0.02 _ROOT = Path(__file__).resolve().parent GROUND_MOTION_FILE = _ROOT / "data" / "BM68elc.acc" REFERENCE_PUSH_TCL = _ROOT / "data" / "Ex2a.Canti2D.ElasticElement.Push.tcl.txt" REFERENCE_EQ_TCL = _ROOT / "data" / "Ex2a.Canti2D.ElasticElement.EQ.tcl.txt" def _ground_motion_values() -> list[float]: return parse_plain_values(GROUND_MOTION_FILE) def build_ex2a_canti2d_elastic_element() -> Project: values = _ground_motion_values() return Project( meta=ProjectMeta( name="OpenSees Ex 2a - Elastic Cantilever Column with Variables", author="OpenSees Wiki / Silvia Mazzoni & Frank McKenna", description=( "Variable-driven elastic cantilever model with derived mass, " "section, pushover, and earthquake analysis parameters." ), units=UnitSystem.US_IN_KIP, ), ndm=2, ndf=3, nodes=[ Node( id=1, name="Base", coords=(0.0, 0.0, 0.0), restraint=(True, True, False, False, False, True), ), Node( id=2, name="Top", coords=(0.0, L_COL, 0.0), mass=(MASS, 1.0e-9, 0.0, 0.0, 0.0, 0.0), ), ], sections=[ ElasticSection( id=1, name="Elastic-Column", E=E_C, A=A_COL, Iz=IZ_COL, Iy=IZ_COL, G=1.0, J=1.0, ), ], elements=[ ElasticBeamColumn( id=1, name="Column", nodes=(1, 2), section_id=1, geom_transf="Linear", ), ], time_series=[ LinearTimeSeries(id=1, name="Gravity"), LinearTimeSeries(id=2, name="Lateral"), PathTimeSeries( id=3, name="BM68elc", dt=GROUND_DT, factor=GROUND_FACTOR, values=values, file_path=str(GROUND_MOTION_FILE.name), ), ], load_patterns=[ PlainLoadPattern( id=1, name="Gravity", time_series_id=1, nodal_loads=[ NodalLoad(node_id=2, forces=(0.0, -P_COL, 0.0, 0.0, 0.0, 0.0)), ], ), PlainLoadPattern( id=200, name="Pushover-X", time_series_id=2, nodal_loads=[ NodalLoad(node_id=2, forces=(H_LOAD, 0.0, 0.0, 0.0, 0.0, 0.0)), ], ), UniformExcitationPattern( id=400, name="GroundMotion-X", direction=1, accel_series_id=3, ), ], analyses=[ StaticCase( id=1, name="Gravity", pattern_ids=[1], n_steps=N_GRAVITY, load_factor_increment=GRAVITY_STEP, system="BandGeneral", constraints="Plain", integrator="LoadControl", algorithm="Newton", test="NormDispIncr", tolerance=1e-8, max_iter=6, ), PushoverCase( id=2, name="Push", preload_case_ids=[1], pattern_ids=[200], control_node=2, control_dof=1, target_disp=PUSH_TARGET, step_size=PUSH_STEP, base_nodes=[1], system="BandGeneral", constraints="Plain", algorithm="Newton", test="EnergyIncr", tolerance=1e-8, max_iter=6, ), TransientCase( id=3, name="Earthquake", preload_case_ids=[1], pattern_ids=[400], dt=ANALYSIS_DT, n_steps=ANALYSIS_STEPS, system="SparseGeneral", constraints="Transformation", integrator="Newmark", integrator_params=(0.5, 0.25), algorithm="ModifiedNewton", test="EnergyIncr", tolerance=1e-8, max_iter=10, rayleigh_mode1_damping=DAMPING_RATIO, ), ], ) def main() -> None: project = build_ex2a_canti2d_elastic_element() project.validate_references() gm = next(ts for ts in project.time_series if ts.id == 3) assert isinstance(gm, PathTimeSeries) print(f"Built '{project.meta.name}'") print(f" LCol={L_COL}, Weight={WEIGHT}, ACol={A_COL:.1f}, Ec={E_C:.3f}") print(f" Gravity + pushover + earthquake cases: {len(project.analyses)}") print(f" Ground motion file: {GROUND_MOTION_FILE.name}") print(f" Reference Tcls: {REFERENCE_PUSH_TCL.name}, {REFERENCE_EQ_TCL.name}") print(f" Record points: {len(gm.values)}, dt = {GROUND_DT}s, factor = {GROUND_FACTOR}") out_path = Path(__file__).with_suffix(".osmodel") save_project(project, out_path) print(f"Saved -> {out_path}") restored = load_project(out_path) restored.validate_references() assert restored.model_dump(by_alias=True) == project.model_dump(by_alias=True) print("Round-trip OK.") if __name__ == "__main__": main()