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026-G09 Lot 1 Contact Contract

Status

Lot 1 is a controlled qualification increment. It does not close 026-G09; the official gate remains NOT_STARTED until the complete contact contract is reviewed and all required lots are closed.

Bounded scope

This lot exercises the existing nonlinear common-driver contribution named frictionless_penalty. Its current contact geometry is a bounded slave-node to triangular-master representation. The cases use a TET4 deformable body and the nonlinear static route with the common Newton residual and tangent assembly. The study covers signed gap, opening/closure/recontact, controlled penalty sensitivity, finite outputs and a structured excessive-penetration failure.

The linear exact active-set route is historical context only and is not mixed with this Lot 1 penalty evidence. Friction, general surface-to-surface contact, finite-sliding qualification, self-contact, external correlation and broader element-family qualification remain outside this lot.

Predeclared policy

Penalty values are [1e2, 1e3, 1e4, 1e5, 1e6]. The evidence records the penetration, signed gap, iterations, relative residual and contact tangent sparsity for every value. The expected internal trend is non-increasing penetration as penalty increases. No universal production penalty range or conditioning cutoff is approved here; that remains an Owner decision.

The controlled failure sets a maximum penetration below the imposed state. It must produce a structured contact failure and must not be counted as a converged case. The runner treats the structured failure result as authoritative for this expected-failure case.

Case mapping

The machine-readable requirements and case registry are:

  • qualification/0_2_6/g09_requirements.json
  • qualification/0_2_6/g09_case_registry.json

READY cases are executed by scripts/run_g09_lot1.py. The registry keeps NOT_SUPPORTED explicit; it is not converted to a pass.

Evidence and limitations

The Lot 1 report and manifest record the source SHA, dirty state, runtime, configuration, predeclared policy and artifact digests. A successful Lot 1 result is internal research evidence only. It does not claim qualification of finite sliding, general surface contact, friction or contact for other element families.