fdscore

fdscore is a Python library for Fatigue Damage Spectrum (FDS) computation and FDS-to-Power Spectral Density (PSD) inversion.

It implements the Henderson-Piersol closed-form inversion method, supports multiple inversion engines (closed form, spectral iterative, and time-domain iterative), and provides utilities for rainflow counting, Dirlik-based spectral fatigue estimation, and Miner-rule damage accumulation.

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Documentation Guide

Use this site as the canonical documentation for installation, workflow guidance, API reference, and theory. The public API documented here matches the stable namespace exposed by fdscore.

The repository also ships a CONTRACTS.md document that defines the public engineering contracts and compatibility rules used across the main release workflows.

Contents

Getting Started

• Installation
  • Requirements
  • Install From PyPI
  • Development Installation
  • Install From Source
• Quickstart
  • Basic Usage
  • What the Output Means
• Examples
  • Available Examples
  • Notes
• Core Concepts
  • Parameter Models
  • Result Objects
  • Compatibility Metadata
  • Normalized and Physical Workflows
  • Reusable Transfer Plans
  • Spectrum Families in fdscore

User Guide

• FDS Workflows
  • Time-Domain FDS
  • Spectral FDS
  • Deterministic Harmonic FDS
  • FDS Algebra
  • Choosing a Route
• ERS Workflows
  • Time-Domain ERS
  • Spectral Random ERS
  • Deterministic ERS
  • ERS Envelope Composition
  • ERS vs Shock Spectra
• Shock Workflows
  • SRS and PVSS
  • Event Detection
  • Rolling SRS and PVSS
  • Shock Envelope Helpers
  • Half-Sine Reduction
• Inversion Workflows
  • Closed-Form Inversion
  • Iterative Spectral Inversion
  • Iterative Time-Domain Inversion
  • Shared Parameter Object
  • Methodological Consistency Between FDS Generation and Inversion
  • Choosing an Engine
  • Choosing the Right FDS-to-PSD Path
  • Diagnostics
• PSD Analysis and Signal Synthesis
  • Welch PSD Estimation
  • Stationary Gaussian Time Synthesis
  • PSD Summary Metrics
  • Choosing the Right Utility
• Compatibility Rules
  • meta["compat"]
  • FDS Algebra Compatibility
  • Inversion Compatibility
  • ERS and Shock Compatibility
  • Public Contract Scope
• Assumptions and Limits
  • Time Synthesis
  • Spectral Fatigue
  • Spectral Random ERS
  • PSD Validity
  • Closed-Form Inversion Scope
  • Closed-Form Inversion Assumptions
  • Cross-Engine Methodological Asymmetry
  • FDSTimePlan Memory Tradeoff
  • Generic ERS vs Shock Backend
  • Rolling Shock Constraints

Reference

• API Reference
  • Configuration Models
  • Result Models
  • Fatigue and Inversion Workflows
  • PSD Analysis and Signal Synthesis
  • Deterministic Harmonic Workflows
  • ERS Workflows
  • Shock Workflows
• Theoretical Background
  • FDS and PSD in fdscore
  • Time-Domain FDS
  • Spectral FDS via Dirlik
  • Henderson-Piersol Closed-Form Inversion
  • Iterative Inversion Engines
• References