## What is amplitude fatigue?

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A constant amplitude fatigue loading (or constant amplitude loading) is a fatigue loading in which all the load cycles are identical. A load cycle is usually called either just a cycle or a fatigue cycle.

## How do you calculate fatigue load?

in MPa, Smax – stress maximum value in a sinusoidal cycle in MPa, Su – material tensile strength in MPa, Sy – yield point of material in MPa, k – exponent in the equation ψN = N-k (log k = 1.973 – log Rm), m(-1) –exponent in the formula describing fatigue (Wöhler) graph for the stress ratio R=-1, ψN – material …

**What is fatigue stress amplitude?**

The stress amplitude at which failure occurs for a given number of cycles is the fatigue strength. N is the number of cycles required for a material to fail at a certain stress range in fatigue life. The stress range, ΔS = Smax–Smin, and number of cyclic loading are defined in Figure 12.2.

**What is constant amplitude fatigue limit?**

These recommendations further suggest that for constant amplitude loading, every 10% reduction in stress range below the knee point results in a one decade increase in fatigue life. Most textbooks include the concept of a fatigue limit which implies that below the knee point, fatigue life becomes infinite.

### Is amplitude a constant?

A steady state amplitude remains constant during time, thus is represented by a scalar. Otherwise, the amplitude is transient and must be represented as either a continuous function or a discrete vector.

### What is a fatigue calculator?

The fatigue calculator is designed to help keep our staff safe. Find out your likelihood of being fatigued in three easy steps.

**What is fatigue load?**

Fatigue loading is the changes observed in a material under the influence of stress generated during cyclic loading. This is generally represented by plotting a stress cycle curve (S-N curve), where S represents stress and N represents the number of cycles to failure.

**What is fatigue strength material?**

Fatigue strength is the highest stress that a material can withstand for a given number of cycles without breaking. Fatigue strength is affected by environmental factors, such as corrosion. The maximum stress that can be applied for a certain number of cycles without fracture is the fatigue strength.

#### What is S and N in S-N curve?

S-N curves An S-N curve defines the number of cycles to failure, N(S), when a material is repeatedly cycled through a given stress range S. OrcaFlex uses the S-N curve to calculate the damage in a fatigue analysis.

#### What is notch sensitivity?

The notch sensitivity of a material is a measure of how sensitive a material is to notches or geometric discontinuities. Notch sensitivity is influenced by many parameters such as notch geometry. Three types of notch geometries, V-shape, U-shape and -shape notches of various sizes are considered in this investigation.

**Does mean stress reduce amplitude for fatigue?**

Effect of mean stress Compressive mean stressdoes not reduce amplitude that can be superimposed -S yS y S y S n σ a -σ m (compression) σ m (tension) G o o d m a n l i n e s empiric concept S u Values from S-N curve (σ m=0) Extends infinite for fatigue (only static failure SNo macroscopic yielding uc Juvinall p.318 Fig. 8.16

**What is the difference between axial loading and fatigue strength?**

maximum stresseson surface weakest point fatigue start Fatigue strength usually slightly greater deliberately neglected safe side Reversed Axial Loading maximum stressesentire cross section no reserve ! Fatigue strength about 10% less eccentric loads about 20…30% less C G=0.7…0.9 gradient factor Reversed Torsional Loading

## What is the effect of fatigue strength on surface?

Fatigue Strength Influence of Surface So far special “mirror polish” surface (only in laboratory ! ) Minimizes 1.) surface scratches (stress concentration) 2.) differences of surface & interior material 3.) residual stresses from finishing Commercial surfaceshave localized points

## What coordinates do you use for fatigue strength?

Standard Fatigue Strength Sn’ Fatigue strength, or Peak alternating stress S (ksi) Linear coordinates (not used for obvious reason) Semilog coordinates Log-log coordinates Ferrous materials: for life cycle N > 106σ< S n’ Knee: 106< N <107