A dynamic ball compression test for understanding rock crushing

Abstract

During crushing, rock particles are subjected to complicated loading. It is desired to establish the relation between the loading and the fragmentation parameters for better understanding rock crushing mechanism. In this work, a split Hopkinson pressure bar system in combination with high speed cameras is utilized in the dynamic ball compression test, in which the spherical rock sample is adopted to avoid the shape effect. Using elasticity theory, the loading rate and the dynamic indirect tensile strength are first calculated. With the aid of the moment-trap technique and high speed cameras, the surface energy is determined for each sample. The relations between the loading rate and the fragmentation parameters, i.e., the number of fragments and the surface energy are established. The application of this method to a granitic rock shows that it is flexible and can be applied to the crushing study of generic brittle solids.

Impact of using lightweight eco-bricks as enclosures for individual houses of one story on zones of high seismicity

“…This test machine includes a load application rate control module, which prevents any error due to the load applying speed. In accordance with UNE 67-026:2002 assays took, at least, more than 60 seconds, otherwise ultimate breaking stress results might be higher than the real ones, as was demonstrated by (20).…”

Método de determinação de resistência à tração e módulo de elasticidade de partí­culas de agregados graúdos naturais.

“…Esses ensaios são classificados conforme o modo de aplicação da carga e o número de pontos de contato em: impacto simples, impacto duplo e compressão lenta, conforme exemplificado na Figura 1.9 [46,47] . Figura 1.9-Diferentes tipos de ensaio de quebra individual de partícula.…”

“…▪ Permitem durante o ensaio o registro da carga aplicada e deslocamento da partícula possibilitando a determinação da curva carga-deslocamento; e então, a energia de fratura da partícula (isto é, a energia consumida durante a quebra da partícula) pode ser determinada [46] .…”