Do Bike Chains Have Infinite Fatigue Life?

For many metals, including steel and aluminum,

no damage occurs once a constant amplitude load drops below the endurance limit

(infinite life). This behavior can be represented by a straight line in a logarithmic diagram called S-N curve.

Does aluminum have infinite fatigue life?

In addition, in the case of aluminum,

there is no fatigue limit

, and inclusions or defects often cause fatigue damage.

Does titanium have infinite fatigue life?

Some materials, like titanium and most steels, have a clear fatigue limit. So below that limit,

the fatigue life is indeed infinite

.

Do all materials have a fatigue limit?

Not all materials have an endurance limit

. For example, rigid, elastic, low damping materials, like some thermoplastics or thermosetting plastics, have a very low or non-existent endurance limit. Endurance limit should not be confused with fatigue strength.

What is fatigue lifetime?

Fatigue life is a mechanical and scientific term that relates to

how long an object or material will last before completely failing because of concentrated stresses

.

How do you get fatigue life?

The number of cycles for the low-cycle fatigue was determined using the Manson-Coffin chart. The calculations made it possible to determine the graphs of fatigue life

Smax = f(λ)

. The fatigue life chart compares the results of calculations for the IM model and the II model with experimental tests.

Does stainless steel fatigue?

Stainless steels exhibit a ‘fatigue limit’ or ‘endurance limit’ during cyclic stressing

. This means that there is a stress level, below which fatigue failure should not occur. This is determined from a series of fatigue tests, run to failure at various stress levels.

Which of the following shows fatigue limit?

Explanation:

All ferrous materials

show fatigue limit. These are cast iron, wrought iron and high and low carbon steels. Austenitic stainless steel is an exception.

Does copper have a fatigue limit?

The standard fatigue strength for copper alloys is that reported for 100,000,000 cycles

. At stresses above this fatigue strength, fewer cycles can be accomplished before failure; at lower stresses, the metal will withstand more cycles before failure.

What is the difference between fatigue limit and endurance limit?

The difference between fatigue limit and endurance limit is that

the endurance limit does not define a limited number of cycles after which the breakdown will occur

. The part basically has infinite life and will not exhibit fatigue failure. It has an indefinite fatigue life.

What affects fatigue life?

Fatigue life

The number of cycles is related to engine speed. It can be converted to equivalent durability hours. Fatigue life is affected by

cyclic stresses, residual stresses, material properties, internal defects, grain size, temperature, design geometry, surface quality, oxidation, corrosion

, etc.

Which metal has no endurance limit?

Representative curves of applied stress vs number of cycles for steel (showing an endurance limit) and

aluminium

(showing no such limit).

Why does aluminium not have endurance limit?

Aluminum does not have an endurance limit such as ferrous metals.

Aluminum will fail if it goes though enough stress cycles

. However, it may be thousands or even millions of cycles before it fails (all depending on the loads/ cycles). Ferrous metals, for example, steel does have an endurance limit.

Does nickel have a fatigue limit?

1. The fatigue limit of 30CrMoA steel plated with electroless nickel is

540 MPa

, a decrease of 39 percent compared with unplated steel (880 MPa).

Which material has endurance limit?

What causes fatigue failure?

What causes fatigue failure? Fatigue failure is

the formation and propagation of cracks due to a repetitive or cyclic load

. Most fatigue failures are caused by cyclic loads significantly below the loads that would result in yielding of the material.

How is fatigue life measured?

Fatigue tests are performed to measure the reduction in stiffness and strength of materials under repeated loading and to determine the total number of load cycles to failure. Fatigue tests are performed by

repeated tension–tension, compression– compression, tension-compression or other combinations of cyclic loading

.

Is fatigue strength the same as yield strength?

In staircase fatigue method, using uniaxial tensile fatigue test and R=0.1, we get a

fatigue limit higher than the Yield Strenght of the material

. In this case: fatigue limit=220 MPa; the Yield Strength = 170 MPa.

What decreases the fatigue strength?

What decreases fatigue strength? Explanation:

Surface smoothness

enhances fatigue strength of a material. Inclusions reduce surface smoothness. Shot peening, case hardening and grain refinement improve tensile strength and fatigue strength.

What is stress life cycle?

Fatigue strength is determined by applying different levels of cyclic stress to individual test specimens and measuring the number of cycles to failure

.

What are the three major approaches to predict fatigue failure?

The three methods used to predict life include

total life (S-N), crack initiation (E-N), and crack growth

.

What is completely reversed stress?

Reversed stresses :

Those stresses which have same magnitude of stresses but in opposite sense

(i.e σ

_{1 =}

-σ

₂

).

Does steel have an endurance limit?

For a large number of steels, there is a direct correlation between tensile strength and fatigue strength;

higher-tensile-strength steels have higher endurance limits

. The endurance limit is normally in the range of 0.35 to 0.60 of the tensile strength.

What is fatigue strength of steel?

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 the fatigue limit of stainless steel?

Discussion of the Different Approaches

The different approaches discussed here are in general agreement on the overall fatigue limit values for stainless steel. – They all agree on a value of around

31.5 ksi at over 108 cycles or higher

.