scholarly journals Thermal shock weakening of granite rock under dynamic loading: 3D numerical modeling based on embedded discontinuity finite elements

2020 ◽  
Vol 44 (13) ◽  
pp. 1788-1811
Author(s):  
Timo Saksala ◽  
Adnan Ibrahimbegovic
2012 ◽  
Vol 16 (4) ◽  
pp. 1101-1124 ◽  
Author(s):  
Shuyu Sun ◽  
Abbas Firoozabadi ◽  
Jisheng Kou

2001 ◽  
Author(s):  
Abhay A. Watwe ◽  
Ravi S. Prasher

Abstract Traditional methods of estimating package thermal performance employ numerical modeling using commercially available finite-volume or finite-element tools. Use of these tools requires training and experience in thermal modeling. This methodology restricts the ability of die designers to quickly evaluate the thermal impact of their die architecture due to the added throughput time required to enlist the services of a thermal analyst. This paper describes the development of an easy to use spreadsheet tool, which performs quick-turn numerical evaluations of the impact of non-uniform die heating. The tool employs well-established finite-volume numerical techniques to solve the steady-state, three-dimensional Fourier equation of conduction in the package geometry. Minimal input data is required and the inputs are customized using visual basic pull-down menus to assist die designers who may not be thermal experts. Data showing comparison of the estimates from the spreadsheet tool with that obtained from a conventional analysis using the commercially available finite element code ANSYS™ is also presented.


Author(s):  
Timo Saksala ◽  
Reijo Kouhia ◽  
Ahmad Mardoukhi ◽  
Mikko Hokka

This paper presents a numerical study on thermal jet drilling of granite rock that is based on a thermal spallation phenomenon. For this end, a numerical method based on finite elements and a damage–viscoplasticity model are developed for solving the underlying coupled thermo-mechanical problem. An explicit time-stepping scheme is applied in solving the global problem, which in the present case is amenable to extreme mass scaling. Rock heterogeneity is accounted for as random clusters of finite elements representing rock constituent minerals. The numerical approach is validated based on experiments on thermal shock weakening effect of granite in a dynamic Brazilian disc test. The validated model is applied in three-dimensional simulations of thermal jet drilling with a short duration (0.2 s) and high intensity (approx. 3 MW m −2 ) thermal flux. The present numerical approach predicts the spalling as highly (tensile) damaged rock. Finally, it was shown that thermal drilling exploiting heating-forced cooling cycles is a viable method when drilling in hot rock mass. This article is part of the theme issue ‘Fracture dynamics of solid materials: from particles to the globe’.


Author(s):  
A. Gagnoud ◽  
Y. Du Terrail-Couvat ◽  
O. Budenkova

Author(s):  
Mohammad R. Aligoodarz ◽  
Mohammad Reza Soleimani Tehrani ◽  
Hadi Karrabi ◽  
Mohammad R. Roshani

Turbo machineries including compressors performance degrades over the period of operation and deviates from design levels due to causes including dust entrance into the compressor, blades mechanical damage, erosion and corrosion. These lead to reduction in compressor performance, efficiency and pressure ratio. Subsequently gas turbine performance is affected since their operation sate is correlated. In this study the numerical investigation of common causes that determine geometric characteristics of a 2-stage centrifugal compressor running in a gas station, including blades fouling and corrosion is performed. 3D Numerical modeling is implemented along with utilization of Shear Stress Transport (SST) turbulence model and independency from the grids is verified.


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