Couple thermal and structural across a transient load

from apex import Aether
from apex.fields import save_field
import os

simos = Aether(api_key=os.environ["APEX_API_KEY"])

# Couple thermal and structural across a transient load step on a turbine blade.
# Stream the trajectory; observe stress field; steer the rollout when a margin
# is approached. Returns a trajectory_id you can later resume or audit.
traj = simos.simulate(
    domain="multiphysics",
    geometry=open("blade.step", "rb").read(),
    geometry_format="step",
    physics=["thermal", "structural"],
    boundary_conditions={
        "inlet":  {"T": 1450, "p": 2.2e6},
        "outlet": {"p": 1.0e5},
        "root":   {"fixed": True},
    },
    materials={"primary": "inconel718"},
    horizon_s=12.0,
    dt_s=5e-3,
    stream=True,
    annotations={"customer_ticket": "BLADE-2026-04"},
)

print(f"trajectory_id = {traj.id}")
print(f"compute_unit_estimate = {traj.compute_units_estimate:.1f}")

for step in traj:
    print(
        f"t={step.time:6.3f}s  "
        f"sigma_max={step.max_stress_MPa:7.1f} MPa  "
        f"T_tip={step.tip_temperature_K:6.1f} K"
    )

    # Steer if we're about to violate the 850 MPa margin.
    if step.max_stress_MPa > 850:
        print("  margin approached — applying root fillet +1.5 mm")
        traj.steer(redesign="root_fillet+1.5mm")

# Save the final stress field for the design-review PDF.
save_field(traj.final_field("vonMises"), "out/blade_vonMises.vti")