Nowadays there is a large number of tunneling projects in progress, mainly in Europe, both for roads and transport supplies. Performance prediction of tunnel boring machines (TBM) and the determination of some design parameters have become crucial, as they are critical elements in planning a project of mechanical excavation. In this paper we use the Discrete Element Method (DEM) to build models...

Based on the damage evolution equation of bearing steel, a user subroutine was developed to simulate fatigue behavior TBM main under condition low speed and heavy load. In addition, law in time domain space studied. Then, nonlinear spring element introduced interaction between roller raceway, vibration response after studied using transient dynamic method. The research shows that risk raceway i...

Abstract Robotic splicing of steel arches is a challenging task that necessary to realize the grasping and docking in limited space. Steel often have mass more than 200 kg length 4 m. Owing large volume high requirements for accurately positioning splicing, it difficult general manipulator meet stiffness requirements. To enhance structural arch manipulator, single-degree-of-freedom (DOF) closed...

Abstract Deep hole drilling processes for high-alloyed materials are characterised by worn guide pads and chatter vibrations. In order to increase feed rates, process stability bore quality in STS deep drilling, various investigations were carried out with adjustments the tool. First, a new chain production of tribologically optimised their effects on pad shape is described detail. The results ...

Bioerosion by boring sponges is an important mechanism shaping the structure of coral reefs all around the world. To determine the excavation rate by boring sponges, we developed a system in which chemical and mechanical boring rates [calcium carbonate (CaCO(3)) dissolution and chip production, respectively] were measured simultaneously in experimental tanks containing reefal rock inhabited by ...

For rotating-tool machining, such as milling, line boring, and cylinder boring, the tool rotation causes the machining force on each tooth to rotate repetitively relative to the inertial coordinate frame. This is quite different than stationary-tool machining, such as turning or boring with a stationary boring bar, in which the force directions are fixed relative to the inertial frame. Although...