Traditional engineering instruction is deductive, beginning with theories and progressing to the applications of those theories Alternative teaching approaches are more inductive Topics are introduced by presenting specific observations, case studies or problems, and theories are taught or the students are helped to discover them only after the need to know them has been established This study reviews several of the most commonly used inductive teaching methods, including inquiry learning, problem-based learning, project-based learning, case-based teaching, discovery learning, and just-in-time teaching The paper defines each method, highlights commonalities and specific differences, and reviews research on the effectiveness of the methods While the strength of the evidence varies from one method to another, inductive methods are consistently found to be at least equal to, and in general more effective than, traditional deductive methods for achieving a broad range of learning outcomes

Inductive Teaching and Learning Methods: Definitions, Comparisons, and Research Bases

DEM/CFD-DEM Modelling of Non-spherical Particulate Systems: Theoretical Developments and Applications

Review: Calibration of the discrete element method

The contribution of DEM to the science of comminution

Simulation of railway ballast using crushable polyhedral particles

Cone crusher modelling and simulation using DEM

Cone crusher performance evaluation using DEM simulations and laboratory experiments for model validation

The discrete element method (DEM) is used for modelling and simulating particle flow behaviour in research and industrial applications. If the results from such a simulation are to be trusted in a research project or be used as knowledge basis in engineering decision making, the modeller will need to apply some kind of calibration and validation approach. Even though most researchers and engineers apply some kind of method for calibration of the model and validation of the results, no general consensus or calibration methodology framework has been established that governs the quality or accuracy. DEM simulations are now used for modelling a vast number of machines and processes in minerals processing. It is hence of essence that the academia and industry continues the process of discussing a methodology for calibrating rock and ore materials. This paper aims at joining this discussion by presenting a general framework. The approach is based on the calibration framework proposed by Hofmann (2005) and adopting it to calibration of DEM models. The framework is based on calibration and validation on three different levels ranging from the basic single contact model parameter calibration; to a mid-level flow property test; to a full scale experiment. A calibration device has been developed in order to facilitate multiple flow regime experiments with directly observable particle flow paths. In order to efficiently perform both calibration experiments and simulations a design of experiments approach is applied. The actual calibration is conducted by minimizing the error between the experimental domain and the simulation domain by applying multi-objective optimization methods.

https://publications.lib.chalmers.se/records/fulltext/222851/local_222851.pdf

Framework for DEM Model Calibration and Validation

The objective of this paper is to simulate the effects of segregation of the feed material entering the hopper on top of a typical cone crusher. A commercially available Discrete Element Method (DEM) software has been used to simulate and demonstrate some important aspects and phenomena and problems that are common in cone crushers. The first phenomenon of interest is segregation and uneven distribution of the feed entering a cone crusher. This is a common problem in many applications and leads to decreased comminution performance, poor product quality, uneven wear of the crusher manganese liners, high stress amplitudes and premature fatigue failures. This problem has been observed in many different applications and can sometimes severely affect the crusher performance in a negative way. A range of possible solutions to address the segregated feed is studied. The internal size reduction process occurring in a cone crusher is also modelled an simulated by applying DEM. The results of the simulations show the dynamics of the crusher and the interaction of the rock material and the machine as well as the breakage and the size reduction process of the rock particles. The results from the DEM simulations of the crushing process are confirming earlier results retrieved by analytical models and simulations. The number of compressive crushing zones is confirmed to be around 10-11 in the studied crusher. The capacity of the crusher is controlled by the choke level. The two different breakage modes, inter and single particle, is clearly seen in the simulations. In addition, some new insights in the internal size reduction process are gained.

Johannes Quist

Papers

The contribution of DEM to the science of comminution

Cone crusher modelling and simulation using DEM

Cone crusher performance evaluation using DEM simulations and laboratory experiments for model validation

Framework for DEM Model Calibration and Validation

Application of discrete element method for simulating feeding conditions and size reduction in cone crushers