레이저 충격 피닝(Laser Shock Peening) 플라스마 충격파 잔류 압축응력 & 1,000Hz 0-Alloc C# 피로 수명 연장 서보 엔진

using System;
using System.Runtime.CompilerServices;

namespace ZeliDesk.Stem.Materials.LaserPeening
{
    /// 

    /// 레이저 충격 피닝 계측 센서 텔레메트리 (0-Alloc Stack Only)
    /// 
    public readonly ref struct LspTelemetry
    {
        public readonly float MeasuredPressureGpa; // [GPa] PVDF 압전 센서 측정 피크 압력
        public readonly float LaserPulseEnergyJ;   // [J] 단일 펄스 레이저 에너지 (예: 5~10 J)
        public readonly float WaterFilmThicknessMm;// [mm] 물 가둠층 두께 (예: 1.0~1.5 mm)
        public readonly float MaterialHelGpa;      // [GPa] 타깃 금속의 HEL 한계 (예: 2.8 GPa)
        public readonly float SpotOverlapRatio;    // [0.0~0.8] 펄스 스팟 중첩률

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public LspTelemetry(
            float measuredPressureGpa,
            float laserPulseEnergyJ,
            float waterFilmThicknessMm,
            float materialHelGpa,
            float spotOverlapRatio)
        {
            MeasuredPressureGpa = measuredPressureGpa;
            LaserPulseEnergyJ = laserPulseEnergyJ;
            WaterFilmThicknessMm = waterFilmThicknessMm;
            MaterialHelGpa = materialHelGpa;
            SpotOverlapRatio = spotOverlapRatio;
        }
    }

    /// 

    /// LSP 제어 및 잔류 응력 연산 결과 구조체
    /// 
    public readonly ref struct LspControlResult
    {
        public readonly float CommandedLaserEnergyDeltaJ; // [J] 레이저 펄스 에너지 보정
        public readonly float CommandedWaterValvePwm;    // [0.0~1.0] 수막 제어 노즐 PWM
        public readonly float EstimatedResidualStressMpa;// [MPa] 표면 잔류 압축 응력 (음수)
        public readonly float CompressiveDepthMm;        // [mm] 압축 응력 유효 깊이
        public readonly bool IsPeeningOptimal;           // 소성 가공 최적 조건 달성 플래그
        public readonly bool IsSurfaceAblationRisk;      // 표면 열적 손상 위험 감지

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public LspControlResult(
            float commandedLaserEnergyDeltaJ,
            float commandedWaterValvePwm,
            float estimatedResidualStressMpa,
            float compressiveDepthMm,
            bool isPeeningOptimal,
            bool isSurfaceAblationRisk)
        {
            CommandedLaserEnergyDeltaJ = commandedLaserEnergyDeltaJ;
            CommandedWaterValvePwm = commandedWaterValvePwm;
            EstimatedResidualStressMpa = estimatedResidualStressMpa;
            CompressiveDepthMm = compressiveDepthMm;
            IsPeeningOptimal = isPeeningOptimal;
            IsSurfaceAblationRisk = isSurfaceAblationRisk;
        }
    }

    /// 

    /// 1,000Hz 실시간 레이저 충격 피닝 서보 제어 엔진
    /// 
    public ref struct LaserShockPeeningEngine
    {
        private const float IdealPressureMultiplier = 2.0f; // HEL의 2.0배 압력이 이상적
        private const float OptimalWaterThicknessMm = 1.2f; // 최적 수막 두께

        /// 

        /// 1ms 주기 충격파 압력 평가, 에너지 피드백 및 수막 제어 루프
        /// 
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public LspControlResult Update(in LspTelemetry telemetry)
        {
            // 1. 타깃 최적 압력 계산 (P_target = 2.0 * HEL)
            float targetPressure = telemetry.MaterialHelGpa * IdealPressureMultiplier;
            float pressureError = targetPressure - telemetry.MeasuredPressureGpa;

            // 2. 레이저 에너지 보정량 산출 (P propto sqrt(I) propto sqrt(E))
            float energyCorrectionJ = Math.Clamp(pressureError * 1.5f, -2.0f, 2.0f);

            // 3. 물 가둠층 노즐 밸브 제어 (두께 1.2mm 유지)
            float thicknessError = OptimalWaterThicknessMm - telemetry.WaterFilmThicknessMm;
            float waterPwm = Math.Clamp(0.5f + (thicknessError * 0.4f), 0.1f, 0.95f);

            // 4. 표면 잔류 압축 응력 및 침투 깊이 추정
            // sigma_res ~= -0.6 * (P_peak - HEL) * (1 + 0.5 * Overlap)
            float excessPressure = MathF.Max(0.0f, telemetry.MeasuredPressureGpa - telemetry.MaterialHelGpa);
            float residualStress = -excessPressure * 250.0f * (1.0f + telemetry.SpotOverlapRatio * 0.6f);
            residualStress = Math.Clamp(residualStress, -900.0f, 0.0f); // 단위: MPa

            // 침투 깊이 (약 1.0~1.8mm)
            float depthMm = (excessPressure / telemetry.MaterialHelGpa) * 1.2f;
            depthMm = Math.Clamp(depthMm, 0.2f, 2.5f);

            // 표면 열적 용융(Ablation) 위험: 수막이 너무 얇거나 압력이 지나치게 낮을 때 플라스마 가둠 실패
            bool ablationRisk = (telemetry.WaterFilmThicknessMm < 0.4f) || (telemetry.MeasuredPressureGpa < 1.5f && telemetry.LaserPulseEnergyJ > 7.0f);
            bool isOptimal = (telemetry.MeasuredPressureGpa >= targetPressure * 0.9f) && !ablationRisk;

            return new LspControlResult(
                commandedLaserEnergyDeltaJ: energyCorrectionJ,
                commandedWaterValvePwm: waterPwm,
                estimatedResidualStressMpa: residualStress,
                compressiveDepthMm: depthMm,
                isPeeningOptimal: isOptimal,
                isSurfaceAblationRisk: ablationRisk
            );
        }
    }
}