scholarly journals A validated co-simulation of grab and moist iron ore cargo: Replicating the cohesive and stress-history dependent behaviour of bulk solids

Author(s):  
M. Javad Mohajeri ◽  
Wilbert de Kluijver ◽  
Rudy L.J. Helmons ◽  
Cees van Rhee ◽  
Dingena L. Schott
2017 ◽  
Vol 34 (6) ◽  
pp. 2031-2053 ◽  
Author(s):  
Guangming Chen ◽  
Dingena L. Schott ◽  
Gabriel Lodewijks

Purpose Sliding wear is a common phenomenon in the iron ore handling industry. Large-scale handling of iron ore bulk-solids causes a high amount of volume loss from the surfaces of bulk-solids-handling equipment. Predicting the sliding wear volume from equipment surfaces is beneficial for efficient maintenance of worn equipment. Recently, the discrete element method (DEM) simulations have been utilised to predict the wear by bulk-solids. However, the sensitivity of wear prediction subjected to DEM parameters has not been systemically investigated at single particle level. To ensure the wear predictions by DEM are accurate and stable, this study aims to conduct the sensitivity analysis at the single particle level. Design/methodology/approach In this research, pin-on-disc wear tests are modelled to predict the sliding wear by individual iron ore particles. The Hertz–Mindlin (no slip) contact model is implemented to simulate interactions between particle (pin) and geometry (disc). To quantify the wear from geometry surface, a sliding wear equation derived from Archard’s wear model is adopted in the DEM simulations. The accuracy of the pin-on-disc wear test simulation is assessed by comparing the predicted wear volume with that of the theoretical calculation. The stability is evaluated by repetitive tests of a reference case. At the steady-state wear, the sensitivity analysis is done by predicting sliding wear volumes using the parameter values determined by iron ore-handling conditions. This research is carried out using the software EDEM® 2.7.1. Findings Numerical errors occur when a particle passes a joint side of geometry meshes. However, this influence is negligible compared to total wear volume of a wear revolution. A reference case study demonstrates that accurate and stable results of sliding wear volume can be achieved. For the sliding wear at steady state, increasing particle density or radius causes more wear, whereas, by contrast, particle Poisson’s ratio, particle shear modulus, geometry mesh size, rotating speed, coefficient of restitution and time step have no impact on wear volume. As expected, increasing indentation force results in a proportional increase. For maintaining wear characteristic and reducing simulation time, the geometry mesh size is recommended. To further reduce simulation time, it is inappropriate using lower particle shear modulus. However, the maximum time step can be increased to 187% TR without compromising simulation accuracy. Research limitations/implications The applied coefficient of sliding wear is determined based on theoretical and experimental studies of a spherical head of iron ore particle. To predict realistic volume loss in the iron ore-handling industry, this coefficient should be experimentally determined by taking into account the non-spherical shapes of iron ore particles. Practical implications The effects of DEM parameters on sliding wear are revealed, enabling the selections of adequate values to predict sliding wear in the iron ore-handling industry. Originality/value The accuracy and stability to predict sliding wear by using EDEM® 2.7.1 are verified. Besides, this research accelerates the calibration of sliding wear prediction by DEM.


Particuology ◽  
2020 ◽  
Vol 50 ◽  
pp. 67-75
Author(s):  
Fang Tao ◽  
Wei Chen ◽  
Jens Plinke ◽  
Craig Wheeler ◽  
Alan Roberts
Keyword(s):  
Iron Ore ◽  

2000 ◽  
Vol 37 (4) ◽  
pp. 764-780 ◽  
Author(s):  
A Burghignoli ◽  
A Desideri ◽  
S Miliziano

This paper presents the findings of a laboratory investigation of the thermomechanical behaviour of clayey soils. The tests were performed on reconstituted and natural clayey soils using triaxial cells modified to control temperature. The range of temperatures that were investigated is from 20° to 60°C. The thermal behaviour of the clays and the influence of temperature on their mechanical behaviour were investigated separately. The analysis of the experimental results obtained in drained and undrained nonisothermal tests and during thermal consolidation made it possible to identify a link between the thermal and the time-dependent behaviour of the soil skeleton. Therefore, as for creep processes, the response of the soil to thermal loading is not unique but among other factors depends strongly on the overall and recent stress history experienced by the soil. In the range of temperatures investigated, the deformability and strength of the soil were found to be relatively independent of temperature. Stiffening of the soil results from thermal cycles.Key words: clay, temperature, creep, stress history, recent stress history.


Author(s):  
E. G. Rightor

Core edge spectroscopy methods are versatile tools for investigating a wide variety of materials. They can be used to probe the electronic states of materials in bulk solids, on surfaces, or in the gas phase. This family of methods involves promoting an inner shell (core) electron to an excited state and recording either the primary excitation or secondary decay of the excited state. The techniques are complimentary and have different strengths and limitations for studying challenging aspects of materials. The need to identify components in polymers or polymer blends at high spatial resolution has driven development, application, and integration of results from several of these methods.


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