Fracture Mechanics: Stress Intensity Factor and Crack Growth

In course

Description

This lecture covers the relationship between crack growth conditions and the energy release rate, defined as the Strain Energy Release Rate G. It explains the stress field ahead of a crack, stress intensity factors, and the effect of cracks on modulus. The instructor introduces the concept of crack-tip energy dissipation and the generalization for ductile materials. The lecture also discusses small-scale yielding and the 'process zone' near the crack tip where all dissipative processes occur.

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An elastic modulus (also known as modulus of elasticity) is the unit of measurement of an object's or substance's resistance to being deformed elastically (i.e., non-permanently) when a stress is applied to it. The elastic modulus of an object is defined as the slope of its stress–strain curve in the elastic deformation region: A stiffer material will have a higher elastic modulus. An elastic modulus has the form: where stress is the force causing the deformation divided by the area to which the force is applied and strain is the ratio of the change in some parameter caused by the deformation to the original value of the parameter.

Shear modulus

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