Continuum Measures of Spall Damage

Abstract

Following the introduction of the concept of continuous spall damage as a replacement for the customary discrete description, existing spall criteria are generalized to continuous measures of damage and are classified according to their dependence on the history of the continuum field variables. A compound-damage-accumulation theory is proposed in which the rate of damage accumulation depends on the existing damage, in addition to the applied stress. Several examples of the application of the new theory to the correlation of existing data are given.

Trans-scale Coupling in Multiscale Simulations

“…We name the accumulated damage contributed by nucleation and growth of microdamage as nucleated damage and grown damage. This is in accord with the concept of simple and compound damage proposed by Davison and Stevens [16]. Therefore the mesoscopic basis of simple and compound damage is nucleated damage and grown damage, respectively.…”

“…The "explosive" increase of D for smaller De * results from the time-dependent growth rate of microdamage,f V (σ,T De * ). This is a reflection of the compound damage noted by Davison and Stevens [16].…”

High-power laser shock-induced dynamic fracture of aluminum and microscopic observation of samples

“…Samples were measured to be fully dense (2.71 g/cm 3 globular grains, whose average diameter is approximately 20 µm. The shock-loaded samples were 10 mm × 10 mm squares of different thicknesses.…”

“…In 1914, Hopkinson firstly observed the spall phenomenon [2] that there were planar separation of material parallel to the wave front when materials under dynamic loads. After the Second World War, driven by engineering and military applications, spall research gets widespread concern and has a great progress [3][4][5]. Since the 1970s, the concepts of damage accumulation and evolution have been proposed as being responsible for the dynamic fracture of ductile metals.…”

Damage evolution, localization and failure of solids subjected to impact loading

“…For example, the particulates in alloys can become the sites of microdamages in spallation. Owing to the rate-dependent nature of spallation there have been various e!orts to formulate this process, such as the integral criterion [1], continuum measure of spallation [2], microstatistical fracture mechanics [3], etc. All these approaches provide progressively helpful means to reveal the essence of this rate-dependent failure process.…”