Elastic energy, release, rupture

The release of elastic energy stored in the fibrils themselves, when they rupture, must be mentioned in developing a model of the separation process for adhering systems. Retraction of fibrils after rupture can be observed visually, in the peeling of a pressure-sensitive tape (11,23). See Figure 2. D611 (2b) reports for PMMA,... 

Griffith s fraeture eriterion can be stated as follows a pre-existing crack in an elastic body will grow if in so doing the elastie stored strain energy released at the instant of rupture is equal to or greater than the amount of surface energy required to create new surfaces. This can be expressed in mathematical form by Equation (5.1) ... 

The resilience, denoted and expressed in Joules (J), is the ability of a solid material to absorb elastic energy and release it when unloaded (e.g., rebound, springback). In practice, the absorbed elastic energy can be calculated from the true stress-strain plot (S - e) by integrating the surface area under the curve between the true yield strength and the origin. This area represents the amount of elastic work per unit volume that can be done on the material without causing it to rupture ... 

When rocks are stressed beyond their elastic limits they undergo a brittle fracture beneath the surface of the Earth. The release of energy gives rise to earthquakes. The point at which the rupture occurs is called the earthquake focus or h)q)ocenter. The geographic point on the Earth s surface directly above the focus is called the epicenter. 

The Mullins effect, which can be considered as a hysteretic mechanism related to energy dissipated by the material during deformation, corresponds to a decrease in the number of elastically effective network chains. It results from chains that reach their limit of extensibility by strain amplification effects caused by the inclusion of undeformable filler particles [24,25]. Stress-softening in filled rubbers has been associated with the rupture properties and a quantitative relationship between total hysteresis (area between the first extension and the first release curves in the first extension cycle) and the enei-gy required for rupture has been derived [26,27]. 

---