ASTM E1049-85 (2023) PDF

Full title and description

St ASTM E1049-85 (2023) — Standard Practices for Cycle Counting in Fatigue Analysis. This standard compiles accepted procedures for counting cycles in irregular load-versus-time histories (level-crossing, peak counting, simple-range, range-pair, and rainflow counting) and provides definitions and rules used when preparing load spectra for fatigue life assessment and damage calculations.

Abstract

ASTM E1049-85 (reapproved 2023) documents established cycle-counting procedures used in fatigue analysis to convert complex time histories of force, stress, strain, torque, acceleration, deflection or other loading parameters into count spectra for damage and life evaluation. It defines counting methods (including the widely used rainflow algorithm), relevant terms (mean crossing, range, peak, valley, etc.), and guidance for producing range–mean matrices or spectra for subsequent S‑N or cumulative-damage analyses.

General information

• Status: Active (reapproved / current as of 2023).
• Publication date: Original adoption 1985; reapproved/last updated 2023 (designation shown as E1049-85R23).
• Publisher: ASTM International.
• ICS / categories: Mechanical testing — ICS code 19.060 (fatigue / mechanical testing).
• Edition / version: Designation E1049-85 (reapproved 2023) — often rendered as E1049-85R23.
• Number of pages: 10 pages (concise practice document).

Scope

These practices provide a compilation of acceptable cycle-counting procedures for use in fatigue analysis and do not prescribe a single preferred method. They cover how to obtain cycle counts from irregular histories using level‑crossing, peak counting, simple‑range, range‑pair and rainflow counting and provide definitions and procedural rules necessary to prepare spectra for life‑prediction methods (e.g., S‑N analysis, Miner's rule). The standard explicitly leaves safety, health and regulatory applicability to the user.

Key topics and requirements

• Definitions of cycle-related terms (peak, valley, range, mean crossing, mean load) and how they apply to counting.
• Level-crossing, peak counting, simple-range, range-pair and rainflow counting procedures (including the simplified rainflow algorithm for repeating histories).
• Rules for handling residual or partial cycles (half cycles, sequence treatment, end effects) and for forming range–mean matrices or spectra for damage summation.
• Guidance for applying cycle counts to fatigue-damage calculations (e.g., preparing inputs for cumulative damage models); the standard is method-agnostic and intended to supply count data rather than mandate a damage model.
• Common practice references and examples used by software and benchmarks implementing the rainflow algorithm (used in many fatigue-analysis tools).

Typical use and users

Used by mechanical, structural and fatigue engineers, test laboratories, analysts performing life-prediction and durability studies, researchers, and software/tool developers who implement cycle-counting algorithms. Typical applications include structural component fatigue assessment, vehicle and aerospace component testing, wind‑turbine and rotating‑equipment fatigue analysis, and post‑processing of measured or simulated time‑history signals prior to S‑N or crack‑growth evaluations.

Related standards

Commonly used alongside standards and documents addressing fatigue testing, terminology and statistical treatment such as ASTM E1823 (fatigue & fracture terminology), ASTM E739 (statistical analysis of S‑N data), various ISO fatigue testing standards (e.g., ISO 1099 and ISO 12107 family), and engineering codes (ASME, IEC/EN standards) that reference cycle‑counting procedures for load spectrum preparation. Several IEC/EN technical documents and sector standards explicitly reference ASTM E1049 for rainflow/simplified rainflow guidance.

Keywords

cycle counting, rainflow counting, fatigue analysis, range–mean matrix, level crossing, peak counting, range‑pair counting, mean crossing, load spectrum, S‑N analysis, cumulative damage.

FAQ

Q: What is this standard?

A: ASTM E1049-85 (reapproved 2023) is a short practice document that compiles accepted cycle‑counting methods used to convert irregular loading time histories into cycle counts and spectra for fatigue life and damage assessment.

Q: What does it cover?

A: It covers procedural rules and definitions for a set of cycle‑counting methods — level‑crossing, peak counting, simple‑range, range‑pair and rainflow — and explains how to treat cycles, partial cycles and how to form counts for subsequent fatigue evaluation. It does not mandate a damage model or a single counting method.

Q: Who typically uses it?

A: Fatigue and structural engineers, test labs, analysts preparing load spectra, software developers implementing rainflow/counting algorithms, and standards bodies or code authors who need a common, documented counting practice.

Q: Is it current or superseded?

A: The document is the original E1049 designation (adopted 1985) and has been reapproved/reaffirmed with the 2023 reapproval (designation E1049-85R23). It is listed as active by ASTM. Users should reference the ASTM document summary for the official status and any editorial changes.

Q: Is it part of a series?

A: E1049 is a standalone practice focused on cycle counting but is commonly used together with other ASTM fatigue standards (terminology, test methods and statistical practices) and with relevant ISO/EN/ASME documents when preparing full fatigue assessments.

Q: What are the key keywords?

A: Key keywords include cycle counting, rainflow, range, mean crossing, load spectrum, fatigue analysis, S‑N, cumulative damage.