feat: initial otko import

examples/concrete04_cantilever.py

@@ -0,0 +1,215 @@
+"""Concrete04 (Popovics) fiber-section cantilever.
+
+A single reinforced-concrete column cantilever using Concrete04 as the
+fiber material, mirroring the ex2c_canti2d_inelastic_fiber_section example
+but with Popovics concrete in place of Kent-Scott-Park (Concrete02).
+
+Run from the repository root:
+
+    python examples/concrete04_cantilever.py
+
+Produces ``examples/concrete04_cantilever.osmodel``.
+"""
+
+from __future__ import annotations
+
+import math
+import sys
+from pathlib import Path
+
+if __package__ is None or __package__ == "":
+    sys.path.insert(0, str(Path(__file__).resolve().parents[1] / "src"))
+
+from otko.core import (  # noqa: E402
+    Concrete04,
+    FiberSection,
+    ForceBeamColumn,
+    LinearTimeSeries,
+    NodalLoad,
+    Node,
+    PlainLoadPattern,
+    Project,
+    ProjectMeta,
+    PushoverCase,
+    RectangularPatch,
+    StaticCase,
+    Steel02,
+    StraightLayer,
+    UnitSystem,
+)
+from otko.services import load_project, save_project  # noqa: E402
+
+# ── Section geometry (SI units: m, N, Pa) ─────────────────────────────────────
+L_COL = 3.0          # column height [m]
+B_COL = 0.30         # section width  [m]
+H_COL = 0.30         # section depth  [m]
+COVER = 0.03         # clear cover    [m]
+
+# ── Material parameters (SI) ───────────────────────────────────────────────────
+FC = -30e6           # peak compressive strength [Pa]  (negative)
+EPSC0 = -0.002       # strain at peak
+EPSCU = -0.005       # ultimate compressive strain
+# Initial tangent: Ec = 4700 * sqrt(|fc| / 1e6) MPa  (ACI 318 formula, SI)
+EC = 4700.0 * math.sqrt(abs(FC) / 1e6) * 1e6   # ≈ 25.74 GPa
+
+FCT = 2.2e6          # tensile strength [Pa]
+ET = 1e-4            # ultimate tensile strain
+
+FY = 420e6           # rebar yield stress [Pa]
+ES = 200e9           # rebar elastic modulus [Pa]
+BS = 0.01            # strain-hardening ratio
+
+NUM_INT_PTS = 5
+N_BARS = 4
+BAR_AREA = 314e-6    # m² (≈ 20 mm diameter rebar)
+
+P_GRAVITY = -300e3   # gravity axial load [N]  (negative = compressive)
+H_LOAD = 50e3        # lateral load at tip [N]
+
+N_GRAVITY = 10
+GRAVITY_STEP = 1.0 / N_GRAVITY
+
+PUSH_TARGET = 0.05 * L_COL    # [m]
+PUSH_STEP = 0.001 * L_COL     # [m]
+
+
+def build_concrete04_cantilever() -> Project:
+    core_y = H_COL / 2.0 - COVER
+    core_z = B_COL / 2.0 - COVER
+
+    return Project(
+        meta=ProjectMeta(
+            name="Concrete04 Cantilever",
+            description=(
+                "Single RC column cantilever using Concrete04 (Popovics) "
+                "fiber section. Demonstrates the Concrete04 material "
+                "end-to-end: schema → model → runner → results."
+            ),
+            units=UnitSystem.SI_M_N,
+        ),
+        ndm=2,
+        ndf=3,
+        nodes=[
+            Node(
+                id=1, name="Base",
+                coords=(0.0, 0.0, 0.0),
+                restraint=(True, True, True, False, False, False),
+            ),
+            Node(id=2, name="Top", coords=(0.0, L_COL, 0.0)),
+        ],
+        materials=[
+            Concrete04(
+                id=1, name="C30-Popovics",
+                fpc=FC, epsc0=EPSC0, epscu=EPSCU, Ec=EC,
+                fct=FCT, et=ET,
+            ),
+            Steel02(
+                id=2, name="Rebar-B500",
+                Fy=FY, E0=ES, b=BS,
+            ),
+        ],
+        sections=[
+            FiberSection(
+                id=1, name="RC-Fiber-C04",
+                patches=[
+                    RectangularPatch(
+                        material_id=1,
+                        n_fib_y=8, n_fib_z=4,
+                        y_i=-H_COL / 2, z_i=-B_COL / 2,
+                        y_j= H_COL / 2, z_j= B_COL / 2,
+                    ),
+                ],
+                layers=[
+                    StraightLayer(
+                        material_id=2,
+                        n_bars=N_BARS, bar_area=BAR_AREA,
+                        y_start=-core_y, z_start= core_z,
+                        y_end  =-core_y, z_end  =-core_z,
+                    ),
+                    StraightLayer(
+                        material_id=2,
+                        n_bars=N_BARS, bar_area=BAR_AREA,
+                        y_start= core_y, z_start= core_z,
+                        y_end  = core_y, z_end  =-core_z,
+                    ),
+                ],
+            ),
+        ],
+        elements=[
+            ForceBeamColumn(
+                id=1, name="Column",
+                nodes=(1, 2),
+                section_id=1,
+                integration_points=NUM_INT_PTS,
+                geom_transf="Linear",
+            ),
+        ],
+        time_series=[
+            LinearTimeSeries(id=1, name="Gravity"),
+            LinearTimeSeries(id=2, name="Lateral"),
+        ],
+        load_patterns=[
+            PlainLoadPattern(
+                id=1, name="Gravity", time_series_id=1,
+                nodal_loads=[
+                    NodalLoad(node_id=2, forces=(0.0, P_GRAVITY, 0.0, 0.0, 0.0, 0.0)),
+                ],
+            ),
+            PlainLoadPattern(
+                id=2, 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)),
+                ],
+            ),
+        ],
+        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=10,
+            ),
+            PushoverCase(
+                id=2, name="Push-X",
+                preload_case_ids=[1],
+                pattern_ids=[2],
+                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=10,
+            ),
+        ],
+    )
+
+
+def main() -> None:
+    project = build_concrete04_cantilever()
+    project.validate_references()
+    print(f"Built '{project.meta.name}'")
+    print(f"  L={L_COL} m, BxH={B_COL}x{H_COL} m, Ec={EC/1e9:.2f} GPa")
+    print(f"  Gravity + pushover cases: {len(project.analyses)}")
+    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()