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Influence of cutting angle on mechanical properties of rock cutting by conical pick based on finite element analysis

Qiao S., Zhang Z. Q., Zhu Z. M., Zhang K.

Mining Science

2021

Vol. 28

161--173

In view of the current situation that it is difficult to obtain the actual cutting force received by the conical pick of Continuous-Miner and to deal with the characteristics of the cutting force. By using contact dynamics, rock mechanics, and finite element methods, based on the display dynamics analysis program ANSYS/LS-DYNA and the Holmquist–Johnson–Cook model, the contact mechanical characteristics between conical pick and rock are analyzed. The resultant force was obtained by obtaining the force curve of the conical pick under X, Y and Z directions, analysis of cutting gear cutting speed of 2.5 m/s, cutting depth of 5, 10, 15, 20 and 25 mm, cutting angle of 30°, 35°, 40°, 45°, 50° parameters of the size of cutting force and cutting ratio energy consumption, thus, the best cutting angle of the conical pick is obtained. The conclusions are as follows: when the cutting depth and cutting speed are constant, and the cutting angle is 45°, the mean cutting force received by the conical pick is the least, the specific energy consumption is the least, and the cutting efficiency is the highest. The best cutting angle of the conical pick should be 45°; When the cutting angle and cutting speed are constant, the energy needed by the cutter to cut the rock increases with the increase of cutting depth. The research results provide a theoretical basis for improving cutting efficiency and cutting life, and for choosing cutting angle and cutting thickness.

The Bionic Lightweight Design of the Mid-rail Box Girder Based on the Bamboo Structure

Cheng W. M., Fu W. G., Zhang Z. Q., Zhang M.

Przegląd Elektrotechniczny

2012

R. 88, nr 9b

113-117

Similar structure and mechanics behavior exist between the bamboo stem and the crane’s box girder. We studied the relation between the structure parameters and mechanics behavior for the bamboo structure and, it showed that the distance of stems increases by the decreasing of the bending moment and the shear force in the bamboo stem. Meanwhile, the permitted maximum distance between two adjacent stiffeners is established by considering the effects of the distance between two adjacent stiffeners on the rigidity and strength design indexes of the box girder. The strategy of the bionic optimization is to allow variable distances between two adjacent stiffeners so that the box girder has uniformly distributed buckling stability. The optimization is carried out by the finite element nonlinear buckling analysis. On the other hand, through case studies we find that the bionic box girder requires smaller number of stiffeners and smaller amount of steel than the traditional box girder. Moreover, the bionic box girder possesses more uniform buckling stability along the direction of its axis.

Struktura dźwigaru żurawi jest podbna do struktury bambusa. W artykule analizowano relacje między strukturą bambusa a jego właściwościami mechanicznymi.