The concept of brittleness plays a crucial role in the development of tight oil and gas as it reflects a rock’s ability to fail and maintain a fracture in a hydraulic fracture experiment. Conventional methods that attempt to quantify the degree of brittleness associated with a rock mass have a few shortcomings. For example, failure criteria are not used and only the effective moduli are conside...

Brittleness of materials—whether it occurs naturally or with aging—affects significantly performance and manifests itself in various properties. In the past, brittleness was defined qualitatively, but now a definition of brittleness for viscoelastic materials exists, enabling analysis of all types of polymer-based materials. The quantity brittleness, B, has been evaluated for neat thermoplastic...

The wear of polymer-based materials is connected to their brittleness. We have previously formulated a quantitative definition of brittleness in terms of elongation at break and storage modulus for thermoplastic polymers. We provide a formula connecting brittleness to viscoelastic recovery (healing) after sliding wear. Our model fits a selection of ten thermoplastics representing several classe...

Though many of the current symbolic problem solvers have attempted to combat "brittleness" with learning procedures, here at the Computing Research Laboratory (CRL) an alternative approach has been developed based on achieving symbolic plasticity through model generation. This paper describes the evolutionary-Model Generative Reasoning (e-MGR) architecture that implements this approach, and dis...

The cold climate is a favorable parameter for the development of tension cracks and decrease of rock brittleness. Therefore, this paper attempts to investigate the Hamekasi porous limestone in order to predict the brittleness indices during freeze-thaw cycles. The freeze–thaw test was executed for one cycle including 16 h of freezing, and 8 h of thawing. The geo mechanical properties and brittl...

Materials are often characterized in terms of their toughness, though more than one definition of toughness exists. Likely the most widely recognized means of defining material toughness, denoted here as τ, is by the area under the stress strain curve from a tensile test. Another important feature describing the nature of materials is that property known as brittleness, which has for a long tim...

the cold climate is a favorable parameter for the development of tension cracks and decrease of rock brittleness. therefore, this paper attempts to investigate the hamekasi porous limestone in order to predict the brittleness indices during freeze-thaw cycles. the freeze–thaw test was executed for one cycle including 16 h of freezing, and 8 h of thawing. the geo mechanical properties and brittl...

assessment of the correlation between rock brittleness and rock fracture toughness has been the subject of extensive research works in the recent years. unfortunately, the brittleness measurement methods have not yet been standardized, and rock fracture toughness cannot be estimated satisfactorily by the proposed indices. in the present study, statistical analyses are performed on some data col...

Assessment of the correlation between rock brittleness and rock fracture toughness has been the subject of extensive research works in the recent years. Unfortunately, the brittleness measurement methods have not yet been standardized, and rock fracture toughness cannot be estimated satisfactorily by the proposed indices. In the present study, statistical analyses are performed on some data col...