fatigue ratio
C2Technical/Specialist
Definition
Meaning
The ratio of fatigue strength (the stress a material can withstand for a given number of cycles without failing) to its ultimate tensile strength.
In engineering and materials science, it quantifies how much the material's resistance to failure under cyclic loading is reduced compared to its maximum static strength.
Linguistics
Semantic Notes
This is a compound technical term where "fatigue" refers specifically to material failure from repeated stress, and "ratio" refers to the mathematical relationship between two measured quantities.
Dialectal Variation
British vs American Usage
Differences
No significant lexical differences. Spelling may follow regional norms (e.g., "behaviour" vs. "behavior" in surrounding text).
Connotations
Identical technical meaning and neutral connotation.
Frequency
Equally rare outside specific engineering contexts.
Vocabulary
Collocations
Grammar
Valency Patterns
The fatigue ratio for [MATERIAL] is typically around 0.5.Engineers determined/calculated the fatigue ratio.A high fatigue ratio indicates good fatigue resistance.Vocabulary
Synonyms
Neutral
Usage
Context Usage
Business
Not used.
Academic
Used in materials science, mechanical engineering, and aerospace engineering research papers and textbooks.
Everyday
Not used.
Technical
Central term in fatigue analysis, structural design, materials testing, and failure analysis reports.
Examples
By Part of Speech
adjective
British English
- fatigue-ratio calculations
- fatigue-ratio data
American English
- fatigue-ratio calculations
- fatigue-ratio data
Examples
By CEFR Level
- The report mentioned the material's fatigue ratio, a key factor for aircraft parts.
- A higher fatigue ratio means the component can handle more stress cycles.
- The aluminium alloy's fatigue ratio of 0.45 was superior to the steel's 0.35 under the same testing conditions.
- We must optimise the design to improve the fatigue ratio without adding excessive weight.
Learning
Memory Aids
Mnemonic
Think of a bridge swaying (fatigue) and a ruler (ratio). The 'fatigue ratio' is like measuring how much sway it can handle versus its maximum push strength.
Conceptual Metaphor
STRENGTH IS A FRACTION (The material's dynamic, long-term strength is a portion of its maximum one-time strength).
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Прямой перевод "отношение усталости" будет непонятен и не является термином. Используйте кальку "коэффициент усталости" или описательный перевод "отношение усталостной прочности к пределу прочности".
Common Mistakes
- Confusing it with 'fatigue life' (number of cycles to failure) or 'safety factor'. Using it as a general synonym for 'tiredness' ratio. Incorrect plural: 'fatigues ratios'.
Practice
Quiz
What does a fatigue ratio of 0.5 imply?
FAQ
Frequently Asked Questions
No. The fatigue ratio is a dimensionless number (a strength ratio). The fatigue limit (or endurance limit) is a specific stress value below which the material theoretically has infinite fatigue life.
It is extremely rare but theoretically possible for certain materials or under specific definitions. Typically, the fatigue strength is less than the ultimate strength, so the ratio is less than 1.
Aerospace, automotive, civil engineering (bridges), and any industry designing components subject to vibration or repeated loading (e.g., turbines, machinery).
It provides a quick, comparative measure of a material's sensitivity to cyclic loading. A designer might choose a material with a higher fatigue ratio for a critical, repeatedly stressed component.