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The fatigue life of metals and some plastics too, can be affected by their surface finishes. Fatigue nearly always starts as a surface crack which spreads across the cross-section of the material and weakens it until it is unable to carry the load and it fails either by direct tension of shear stress on the uncracked remnant of the original cross-section.
The surface finish of the material contributes adversly to the initiatian period before a crack starts, and when the surface is rough a stress concentration is present there. When there is no roughness present the crystaline nature of the material itself may be the cause of the crack starting. But when the surface is rough this process is faster due to having greater local stresses. So with increasingly rougher surfaces the fatigue life becomes progressively shorter.
Depending on the spectrum of applied loads, this very local stress is responsible for the initiation of the crack which spreads with time. In sheet metal the spread is slow but in heavy solid pieces of metal, the speed of the crack is much faster so the start and finishing times are not very different.
What else can I help you with?
What is Effect of corrosion on fatigue life?
Yes it will bring down the fatigue life and the material will not endure at any point. Degrading nature of fatigue loading on the materials is compounded by the corrosion interaction. Synergistic damage - The damage will be more than the addition of damages due to corrosion and fatigue loading. The formation of intrusion and extrusion due to fatigue loading leads to the notches. The corrosion media will enter the notches and forms oxide with the base metal and it will be passive to further corrosion. But the fatigue loading will disturb the passive layer and facilitate the media to corrode the fresh material. Hence it will drastically decrease the fatigue life of the material.
Can the same material have high fatigue life but low strength?
Im going to throw in the trick answer: change the shape of the part in question to improve the fatigue and strength properties of the material in question.Answer 2Yes. Fatigue requires repeated cycles of loading. If you design a part with low strength but only has a few load cycles throughout the life of the part, then it will never fatigue.There are several application of Bolts that have low fatigue loading cycles. The screws attaching the interior of your car are low strength and they last forever---because there is very little load cycles applied to it.Another example: Wooden chair legs never break under fatigue. I wouldn't say that they are high strength part.
What is fatigue strength?
Fatigue life is the number of cycles a structure part can take before it breaks. A cycle is when the stress reverses or changes about its mean value as happens during vibration for example. Usually fatigue life is expressed in number of cycles; for example a steel part of a given strength may have its strength reduced in half after 1,000,000 cycles due to fatigue.
Why don't we draw out the Circuit diagram all the time?
Because the components are much more detailed and difficult to draw in real life
What is the lifespan of a windmill?
Design life is 30 years; with normal repair cycles most components have a 50% chance of being exchanged once.
What is the effect on tool life surface finish and dimensional accuracy when applying roughing and finishing cuts?
Tool life is greatly shortened when used for both roughing and finishing thus affecting dimensional accuracy and surface finish badly as tool begin to wear off or get chipped, whereas, tool life gets longer when different tools are being used for roughing and finishing again dimensional accuracy and surface finish is affected but this time by achieving good results.
What has the author Paul Anthony Bartolotta written?
Paul Anthony Bartolotta has written: 'Fatigue life prediction of an intermetallic matrix composite at elevated temperatures' -- subject(s): Fatigue life, Metal fatigue, Thermal fatigue, Metal matrix composites
What has the author Waloddi Weibull written?
Waloddi Weibull has written: 'The static strength and the fatigue strength of riveted, spotwelded and redux-bonded joints in 24 ST aluminium alloy sheet' 'A new method for the statistical treatment of fatigue data' 'Scatter of fatigue life and fatigue strength in aircraft structural materials and parts' 'Scatter in fatigue life of 24S-T alclad specimens with drilled holes'
What is the definition of pathological fatigue?
Pathological fatigue refers to extreme and persistent tiredness that is not alleviated by rest. It can be a symptom of various medical conditions, such as chronic fatigue syndrome, multiple sclerosis, or fibromyalgia. It significantly impacts daily functioning and quality of life.
What has the author Fernand Ellyin written?
Fernand Ellyin has written: 'Fatigue damage, crack growth, and life prediction' -- subject(s): Service life (Engineering), Materials, Fatigue, Fracture mechanics, Stress corrosion
Is life worth?
finish it and see
What has the author F H Hooke written?
F. H. Hooke has written: 'Some problems of fatigue life estimation' -- subject(s): Fatigue, Materials
What is Effect of corrosion on fatigue life?
Yes it will bring down the fatigue life and the material will not endure at any point. Degrading nature of fatigue loading on the materials is compounded by the corrosion interaction. Synergistic damage - The damage will be more than the addition of damages due to corrosion and fatigue loading. The formation of intrusion and extrusion due to fatigue loading leads to the notches. The corrosion media will enter the notches and forms oxide with the base metal and it will be passive to further corrosion. But the fatigue loading will disturb the passive layer and facilitate the media to corrode the fresh material. Hence it will drastically decrease the fatigue life of the material.
Can fatigue cause death?
Fatigue by itself is a sign, a symptom. In and of itself, ordinary fatigue would not be seen as a life threatening condition. However the cause of the fatigue is another matter. There could be an underlying condition in some cases that is life threatening and this could only be clarified by physicians. Also, ordinary fatigue can be and is routinely implicated in accidental deaths during the operation of machinery or automobiles, or while engaging in otherwise dangerous or very exacting activities like skiing, diving, climbing.
What has the author Kunihiro Iida written?
Kunihiro Iida has written: 'Life distribution and design curve in low cycle fatigue' -- subject(s): Fatigue, Structural Steel
When lost will finish?
After life it's self
What percentage of ocean life exists near the surface?
about 95% of ocean life exists near the surface. about 95% of ocean life exists near the surface.
