Roymech engineering encyclopedia

Fatigue Failure, Stress Concentrations and Material Behaviour




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Fatigue is the progressive damage of a material subjected to repeated or fluctuating loading and can result in failure at stresses below the material's static strength. This section provides engineering guidance and reference data for fatigue life, cyclic loading, stress concentrations, endurance factors, fatigue resistance, high-cycle fatigue and impact loading.

Jump to:  Metal Fatigue & Endurance   Stress Concentration Factors   fatigue_loading   Fatigue & Endurance Factors Fatigue Life   Fatigue Resistance Impact Loading (Fatigue) High Cycle Fatigue Strength

Often machine members subjected to repeated stressing are found to have failed even when the actual maximum stresses were below the ultimate strength of the material, and quite frequently at stress values even below the yield strength. The most distinguishing characteristics is that the failure had occurred only after the stresses have been repeated a very large number of times. Hence the failure is called fatigue failure

Metal Fatigue & Endurance

Introduction to metal fatigue, endurance, cyclic loading and cumulative fatigue damage.

Metal Fatigue & Endurance

Stress Concentration Factors

Stress concentration factors for geometric discontinuities, notches, fillets, holes and other changes in component geometry.

Stress Concentration Factors

Fatigue Loading

Alternating, repeated and combined cyclic stresses, including mean stress, stress amplitude and stress ratio.

Fatigue Loading

Fatigue & Endurance Factors

Factors used to modify fatigue and endurance strength for practical component design and operating conditions.

Fatigue & Endurance Factors

Fatigue Life

Guidance on static, low-cycle, finite-life and high-cycle loading, including cumulative fatigue damage.

Fatigue Life

Improving Fatigue Resistance

Design, geometry, manufacturing and treatment methods for reducing stress concentrations and improving fatigue resistance.

Fatigue Resistance

Impact Loading

Impact stress and deflection, gravity and kinetic impact, beam loading, energy effects and stress waves.

Impact Loading

High Cycle Fatigue Strength

Estimating finite-life fatigue strength from S-N relationships between low-cycle strength and endurance strength.

High Cycle Fatigue Strength

Useful Links..
  1. FatigueCalculator.com... Excellent Source of Fatigue data. (Based on US materials )
  2. Metal Fatigue examples... Open University Notes and pictures
  3. Comparison of fatigue provisions in codes and standards... HSE down load related to offshore industry
  4. ExcelCalcs... Excellent facility for Engineers. Library includes Fatigue calculator based on Roymech. (Membership required).
  5. Fatigue Basics -epi_eng ...Useful set of notes