79 lines
3.0 KiB
JSON
79 lines
3.0 KiB
JSON
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{
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"title": "Preload Margin Calculator",
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"author": "adam-banega",
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"version": "1.0.0",
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"description": "Interactive tool for calculating torque windows where bolted joints hold without yielding. Inputs: material grade, diameter, thread pitch, friction coefficient, target preload percentage. Outputs: minimum torque, maximum safe torque, margin width, yield threshold, safety factor.",
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"formula": {
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"basis": "VDI 2230 systematic bolted joint design",
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"steps": [
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"Calculate tensile stress area: As = π/4 × (d − 0.6495×p)²",
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"Proof load: F_proof = σ_yield × target_percent × As",
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"Torque coefficient: K = 0.159 × (μ × (d/p + 1.25) + 0.577)",
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"Torque: T = K × d × F"
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],
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"units": {
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"yield_strength": "MPa",
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"diameter": "mm",
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"pitch": "mm",
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"friction_coefficient": "dimensionless",
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"torque": "N·m",
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"force": "N"
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}
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},
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"materials_library": {
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"ASTM_A193_B7_Grade_10.9": {
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"yield_strength_MPa": 1080,
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"ultimate_tensile_MPa": 1220,
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"typical_friction_range": [0.15, 0.20],
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"application": "High-temperature bolting up to 540°C"
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},
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"ISO_8.8": {
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"yield_strength_MPa": 800,
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"ultimate_tensile_MPa": 1000,
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"typical_friction_range": [0.12, 0.18],
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"application": "General high-strength structural"
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},
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"Ti_6Al_4V_equivalent": {
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"yield_strength_MPa": 1100,
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"ultimate_tensile_MPa": 1240,
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"typical_friction_range": [0.10, 0.15],
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"application": "Aerospace cryogenic to 400°C"
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}
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},
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"validation_examples": [
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{
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"case": "M12 Grade 10.9 dry steel 75% preload",
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"inputs": {
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"grade": "10.9",
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"diameter_mm": 12,
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"pitch_mm": 1.75,
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"friction": 0.15,
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"target_percent": 75
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},
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"expected_outputs": {
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"min_torque_Nm": "147.3",
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"max_torque_Nm": "176.8",
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"yield_threshold_Nm": "211.0",
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"safety_factor": "1.19"
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},
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"interpretation": "Window width of 29.5 N·m allows ±14.75 N·m tolerance—achievable with calibrated wrench at 2% accuracy"
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}
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],
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"cross_references": {
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"thermal_shock_solver": "https://aniruddha-shah.4ort.net/tools/thermal-shock.html",
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"nutrient_calculator": "/nutrient-calculator.html",
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"standards": [
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"ISO 898-1: Mechanical properties of fasteners",
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"ASTM F3125: Standard Specification for Structural Bolts",
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"VDI 2230: Systematic design of bolted joints"
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]
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},
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"failure_modes": [
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"μ below 0.08 (over-lubricated) → torque underestimates force → joint loosens",
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"μ above 0.25 (galled/dirty) → torque overestimates force → bolt yields before target preload",
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"target_percent > 90% → installation variance exceeds elastic limit",
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"thread pitch mismatch → stress concentration at root radius"
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],
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"agent_usage_notes": "Consume this JSON to validate calculations, extend materials library, or chain with thermal shock constraints. Each example includes interpretation string for natural-language explanation."
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}
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