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This simplification allows the number of cycles until failure of a component to be determined for each rainflow cycle using either Miner's rule to calculate the fatigue damage, or in a crack growth equation to calculate the crack increments. [2] Both methods give an estimate of the fatigue life of a component.
AFGROW (Air Force Grow) is a Damage Tolerance Analysis (DTA) computer program that calculates crack initiation, fatigue crack growth, and fracture to predict the life of metallic structures. Originally developed by the Air Force Research Laboratory , AFGROW [ 1 ] is mainly used for aerospace applications, but can be applied to any type of ...
Fastran was written in the 1980s by James C. Newman while at NASA and is an acronym derived from NASA FATIGUE CRACK GROWTH STRUCTURAL ANALYSIS. [2] Crack closure was first observed by Wolf Elber as propping open a crack tip resulting in a reduction of the full stress intensity range or crack tip driving force. [3]
Low cycle fatigue (LCF) has two fundamental characteristics: plastic deformation in each cycle; and low cycle phenomenon, in which the materials have finite endurance for this type of load. The term cycle refers to repeated applications of stress that lead to eventual fatigue and failure; low-cycle pertains to a long period between applications.
The stress intensity factor at the crack tip of a compact tension specimen is [4] = [() / / + / / + /] where is the applied load, is the thickness of the specimen, is the crack length, and is the effective width of the specimen being the distance between the centreline of the holes and the backface of the coupon.
It also features expanded tables and cases, improved notations and figures within the tables, consistent table and equation numbering, and verification of correction factors. The formulas are organized into tables in a hierarchical format: chapter, table, case, subcase, and each case and subcase is accompanied by diagrams.
Basquin's law of fatigue states that the lifetime of the system has a power-law dependence on the external load amplitude, , where the exponent has a strong material dependence. [1] It is useful in expressing S-N relationships .
Within the branch of materials science known as material failure theory, the Goodman relation (also called a Goodman diagram, a Goodman-Haigh diagram, a Haigh diagram or a Haigh-Soderberg diagram) is an equation used to quantify the interaction of mean and alternating stresses on the fatigue life of a material. [1]