{
  "$schema": "https://slfy.solidify.studio/schema/slfy-0.1.schema.json",
  "format": "slfy",
  "version": "0.1",
  "model": {
    "id": "shaft-in-torsion",
    "title": "Solid shaft in torsion",
    "summary": "A solid shaft whose diameter and torque are sliders; the shear stress and twist follow live.",
    "units": "mm",
    "parameters": [
      {
        "id": "d",
        "label": "Shaft diameter",
        "symbol": "d",
        "value": 40,
        "min": 20,
        "max": 80,
        "step": 1,
        "unit": "mm"
      },
      {
        "id": "L",
        "label": "Shaft length",
        "symbol": "L",
        "value": 600,
        "min": 300,
        "max": 1000,
        "step": 10,
        "unit": "mm"
      },
      {
        "id": "T",
        "label": "Torque",
        "symbol": "T",
        "value": 500,
        "min": 50,
        "max": 2000,
        "step": 10,
        "unit": "N·m"
      },
      {
        "id": "G",
        "label": "Shear modulus",
        "symbol": "G",
        "value": 80,
        "min": 25,
        "max": 85,
        "step": 1,
        "unit": "GPa"
      },
      {
        "id": "rpm",
        "label": "Speed",
        "symbol": "N",
        "value": 120,
        "min": 0,
        "max": 600,
        "step": 10,
        "unit": "rpm"
      }
    ],
    "parts": [
      {
        "id": "shaft",
        "name": "Shaft",
        "material": "steel",
        "role": "moving",
        "rotation": [
          0,
          0,
          1.5708
        ],
        "explode": [
          0,
          0,
          0.1
        ],
        "info": {
          "summary": "A solid round shaft carrying torque T.",
          "role": "Sizes are in metres, so the millimetre sliders are divided by 1000 in each size."
        },
        "motion": {
          "kind": "rotate",
          "axis": "y",
          "speed": "rpm * 2 * pi / 60 / 10"
        },
        "shapes": [
          {
            "kind": "cylinder",
            "r": "d / 2000",
            "h": "L / 1000"
          }
        ]
      },
      {
        "id": "bearing_left",
        "name": "Left bearing",
        "material": "castIron",
        "role": "static",
        "explode": [
          0,
          0,
          0.1
        ],
        "mount": {
          "kind": "coaxial",
          "target": "shaft",
          "at": 0.1
        },
        "shapes": [
          {
            "kind": "tube",
            "rOuter": "d / 2000 + 0.02",
            "rInner": "d / 2000",
            "h": 0.03
          }
        ]
      },
      {
        "id": "bearing_right",
        "name": "Right bearing",
        "material": "castIron",
        "role": "static",
        "explode": [
          0,
          0,
          0.1
        ],
        "mount": {
          "kind": "coaxial",
          "target": "shaft",
          "at": 0.9
        },
        "shapes": [
          {
            "kind": "tube",
            "rOuter": "d / 2000 + 0.02",
            "rInner": "d / 2000",
            "h": 0.03
          }
        ]
      }
    ],
    "annotations": [
      {
        "id": "torque",
        "kind": "moment",
        "label": "T",
        "magnitude": "T",
        "unit": "N·m",
        "anchor": {
          "part": "shaft",
          "at": "end"
        }
      },
      {
        "id": "length",
        "kind": "dimension",
        "label": "L",
        "anchor": {
          "part": "shaft"
        }
      }
    ],
    "calculations": [
      {
        "id": "J",
        "label": "Polar second moment of area",
        "symbol": "J",
        "formula": "pi * (d / 1000) ^ 4 / 32",
        "unit": "m⁴",
        "latex": "J = \\frac{\\pi d^4}{32}"
      },
      {
        "id": "tau",
        "label": "Maximum shear stress",
        "symbol": "tau",
        "formula": "T * (d / 2000) / J / 1e6",
        "unit": "MPa",
        "latex": "\\tau = \\frac{T r}{J}",
        "limit": {
          "kind": "max",
          "value": 80,
          "label": "allowable"
        }
      },
      {
        "id": "theta",
        "label": "Angle of twist",
        "symbol": "theta",
        "formula": "T * (L / 1000) / (G * 1e9 * J) * 180 / pi",
        "unit": "°",
        "latex": "\\theta = \\frac{T L}{G J}"
      },
      {
        "id": "P",
        "label": "Power transmitted",
        "symbol": "P",
        "formula": "T * rpm * 2 * pi / 60 / 1000",
        "unit": "kW",
        "latex": "P = \\frac{2 \\pi N T}{60}"
      }
    ],
    "charts": [
      {
        "id": "tau_r",
        "title": "Shear stress across the radius",
        "x": {
          "label": "r",
          "unit": "mm",
          "from": "0",
          "to": "d / 2"
        },
        "y": {
          "label": "τ",
          "unit": "MPa"
        },
        "series": [
          {
            "id": "t",
            "label": "τ",
            "formula": "T * (x / 1000) / J / 1e6"
          }
        ]
      }
    ]
  },
  "view": {
    "camera": {
      "position": [
        0.45,
        0.3,
        0.55
      ],
      "target": [
        0,
        0,
        0
      ]
    },
    "extent": 0.6,
    "floorY": -0.08,
    "cut": {
      "enabled": false,
      "normal": [
        0,
        0,
        1
      ],
      "pos": 0
    }
  },
  "meta": {
    "generator": "Solidify (solidify.studio)",
    "license": "CC-BY-4.0",
    "created": "2026-11-10"
  }
}