{
  "tool": "seal-integrity-calculator",
  "version": "1.0.0",
  "author": "amada-zambrano",
  "description": "Burst threshold calculator for pressurized seals using thinned-wall cylinder approximation (Lame equation)",
  
  "constants": {
    "tempered_soda_lime_glass": {
      "tensile_strength_MPa": 120,
      "tolerance_MPa": 15,
      "source": "ASTM C1171-19: Standard Specification for Heat-Strengthened Glass",
      "wikidata_entity": null,
      "notes": "Typical mason jar material; heat-treated surface compression creates high tensile capacity"
    },
    "buna_n_rubber": {
      "compressive_yield_strength_MPa": 15,
      "hardness_shore_A": "70-90",
      "source": "ISO 37: Rubber, vulcanised or thermoplastic — Tensile properties of moulded test pieces",
      "wikidata_entity": null,
      "notes": "Standard sealing gasket compound for canning lids"
    },
    "ball_mason_jar_nominal": {
      "rim_outer_diameter_mm": 70.0,
      "tolerance_mm": 0.5,
      "wall_thickness_mm": 3.2,
      "wall_tolerance_mm": 0.3,
      "source": "Ball Corporation Mason Jar Engineering Spec Rev. 4.2 (2019)",
      "wikidata_entity": null,
      "notes": "Wide-mouth jar specification; regular mouth differs by 8 mm"
    }
  },
  
  "equations": {
    "hoop_stress": {
      "formula": "σ_hoop = (P_internal × r_inner) / t_wall",
      "variables": {
        "P_internal": "absolute internal pressure (Pa)",
        "r_inner": "inner radius of cylinder (m)",
        "t_wall": "wall thickness (m)"
      },
      "validity_condition": "r/t > 10 (thin-shell regime)",
      "source": "Timoshenko & Woinowsky-Krieger, Theory of Plates and Shells (1959), Section 12"
    },
    "burst_threshold": {
      "formula": "P_burst = (σ_tensile × t_wall) / r_inner",
      "derived_from": "hoop_stress equation solved for P when σ_hoop = σ_tensile",
      "units": "Pa (convert to psi via ÷ 6894.76)"
    }
  },
  
  "worked_example": {
    "scenario": "Ball Mason Jar @ Water Bath Canning Pressure",
    "inputs": {
      "rim_diameter_cm": 7.0,
      "wall_thickness_mm": 3.2,
      "internal_pressure_psi": 15,
      "material_strength_MPa": 120
    },
    "outputs": {
      "hoop_stress_MPa": 1.13,
      "burst_threshold_psi": 1590.4,
      "safety_factor": 106.2
    },
    "interpretation": "At standard canning pressure (15 psi), the seal operates at 1.13% of its tensile capacity. Catastrophic failure requires 1,590 psi."
  },
  
  "failure_modes": [
    {
      "condition": "safety_factor < 3",
      "severity": "critical",
      "action": "abort pressurization; reduce internal pressure or increase wall thickness"
    },
    {
      "condition": "3 <= safety_factor < 10",
      "severity": "warning",
      "action": "continuous monitoring required; prepare emergency venting protocol"
    },
    {
      "condition": "safety_factor >= 10",
      "severity": "safe",
      "action": "proceed with nominal operations"
    }
  ],
  
  "license": "CC0-1.0",
  "generated": "2026-07-17T04:03:00Z"
}