Marin endurance limit API

Corrects the rotating-beam endurance limit with the Shigley Marin factors (surface ka, size kb, load kc, temperature kd, reliability ke), returning the adjusted Se and each factor. Answers 'What endurance limit should I use for my actual part finish, size and reliability?'.

Price$0.08per request

MethodPOST

Route/v1/engineering/marin-endurance-limit

StatusLive

MIME typeapplication/json

Rate limit120/minute

Cache0s public

fatigueendurance-limitmarin-factorsshigleysurface-finishreliabilitysize-factormachine-design

API URLhttps://x402.hexl.dev/v1/engineering/marin-endurance-limit

Integration docs

Example request

{
  "ultimateStrengthMpa": 600,
  "surfaceFinish": "machined",
  "diameterMm": 10,
  "loadType": "bending",
  "reliabilityPct": 99
}

Example response

{
  "enduranceLimitMpa": 195.9448,
  "rotatingBeamLimitMpa": 300,
  "factors": {
    "ka_surface": 0.82788,
    "kb_size": 0.96922,
    "kc_load": 1,
    "kd_temp": 1,
    "ke_reliability": 0.814
  },
  "formula": "Se = ka·kb·kc·kd·ke·Se', Se' = min(0.5·Sut, 700 MPa)",
  "interpretation": "Surface finish and load type usually dominate; axial loading drops the limit ~15% (kc=0.85)."
}

Input schema

{
  "type": "object",
  "required": [
    "ultimateStrengthMpa"
  ],
  "properties": {
    "ultimateStrengthMpa": {
      "type": "number",
      "examples": [
        600
      ]
    },
    "rotatingBeamLimitMpa": {
      "type": "number",
      "examples": [
        300
      ]
    },
    "surfaceFinish": {
      "type": "string",
      "enum": [
        "ground",
        "machined",
        "cold-drawn",
        "hot-rolled",
        "as-forged"
      ],
      "examples": [
        "machined"
      ]
    },
    "diameterMm": {
      "type": "number",
      "examples": [
        10
      ]
    },
    "loadType": {
      "type": "string",
      "enum": [
        "bending",
        "axial",
        "torsion"
      ],
      "examples": [
        "bending"
      ]
    },
    "tempFactorKd": {
      "type": "number",
      "examples": [
        1
      ]
    },
    "reliabilityPct": {
      "type": "number",
      "enum": [
        50,
        90,
        95,
        99,
        99.9,
        99.99
      ],
      "examples": [
        99
      ]
    }
  }
}

Output schema

{
  "type": "object",
  "additionalProperties": true
}