A component made of 7075-T6 aluminum alloy has an edge crack of 1.4 mm in length. Plane strain fracture toughness of this alloy is given as 27 MPA\M. Geometrical factor of the crack is given as 1.2. (a) If this alloy is subjected to uniaxial tensile stress of 380 MPa, determine whether sudder brittle fracture occurs or not. (b) Calculate the maximum allowable crack size for this component in order not to be failed ir brittle manner under a stress of 1000 MPa
Design Against Fluctuating Loads
Machine elements are subjected to varieties of loads, some components are subjected to static loads, while some machine components are subjected to fluctuating loads, whose load magnitude tends to fluctuate. The components of a machine, when rotating at a high speed, are subjected to a high degree of load, which fluctuates from a high value to a low value. For the machine elements under the action of static loads, static failure theories are applied to know the safe and hazardous working conditions and regions. However, most of the machine elements are subjected to variable or fluctuating stresses, due to the nature of load that fluctuates from high magnitude to low magnitude. Also, the nature of the loads is repetitive. For instance, shafts, bearings, cams and followers, and so on.
Design Against Fluctuating Load
Stress is defined as force per unit area. When there is localization of huge stresses in mechanical components, due to irregularities present in components and sudden changes in cross-section is known as stress concentration. For example, groves, keyways, screw threads, oil holes, splines etc. are irregularities.
Step by step
Solved in 3 steps
