Two types of alumina-based cutting tools with compositions of 90 vol.% Al2O3+10 vol.% ZrO2 and 80 vol.% A12O3+20 vol.% TiC are produced by isostatic pressing and sintering technique. The effects of these additives on the mechanical properties and cutting performance of these materials are investigated. The tool life in both materials is examined under identical conditions on cutting a grey cast...

In the process of turning, pointing at the uncertain phenomenon of cutting which is caused by the disturbance of random factors, for determining the uncertain scope of cutting force, the integrated symmetric fuzzy number and the finite element method (FEM) are used in the prediction of cutting force. The method used symmetric fuzzy number to establish fuzzy function between cutting force and th...

According to the movement characteristics of surrounding rock gob-side entry retaining by roof cutting (GERRC), structural evolution mechanism and stability control countermeasures are studied in this paper. Taking bulking as core point, process GERRC is divided into five stages: cutting, dynamic pressure support, gangue bulking, double arch roadway formation. Combined with mechanical analysis,...

Abstract The rock uniaxial compressive strength (UCS) is the basic parameter for support designs in underground engineering. In particular, UCS should be obtained rapidly engineering with complex geological conditions, such as soft rock, fracture areas, and high stress, to adjust excavation plan ensure construction safety. To solve problem of obtaining real-time at sites, a forecast idea propos...

Although we know that our lineage has been producing sharp-edged tools for over 2.6 Myr, our knowledge of what they were doing with these tools is far less complete. Studies of these sharp-edged stone tools show that they were most probably used as cutting implements. However, the only substantial evidence of this is the presence of cut marks on the bones of animals found in association with st...

We study the structural instability mechanism and effect of a multi-echelon support in very-deep roadways. We conduct a scale model test for analysing the structural failure mechanism and the effect of multi-echelon support of roadways under high horizontal stress. Mechanical bearing structures are classified according to their secondary stress distribution and the strength degradation of the s...