| 1. |
- Kou, Shao Quan, et al.
(författare)
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Numerical investigation of particle breakage as applied to mechanical crushing—Part II: Interparticle breakage
- 2001
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Ingår i: International Journal of Rock Mechanics And Mining Sciences. - 1365-1609 .- 1873-4545. ; 38:8, s. 1163-1172
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Tidskriftsartikel (refereegranskat)abstract
- A numerical approach to interparticle breakage is applied using the rock failure process analysis code, RFPA2D. A 2D particle assembly in a container is first numerically simulated to obtain the fringe patterns of stress fields that resemble the photoelastic test. Then, in addition, the interparticle breakage of the particle assembly in a chamber is conducted. The chamber consists of a steel container and a steel platen for transferring the load, and contains 15 particles of arbitrary sizes and irregular shapes. A plane strain condition is assumed. The particle bed is loaded under form conditions, in which the size reduction and the applied force are a function of the displacement. The numerical results indicate that, during the crushing process, three principal regimes appear: (i) the elastic deformation regime, where each particle deforms elastically; (ii) the fragmentation regime, where the particle assembly is crushed in a particle-by-particle fashion; and (iii) the assembly hardening regime, where the densified assembly recovers a significant stiffness. The dominant mode of failure is at first splitting, which is more or less parallel to the loading direction, and then progressive crushing, which mainly depends on the confinement from the chamber walls. The analysis of the load–displacement curves of the assembly obtained from the simulations reveals a high undulating load plateau, which suggests a macro-ductile behaviour.
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| 2. |
- Kou, Shao Quan, et al.
(författare)
-
Numerical simulation of the cutting of inhomogeneous rocks
- 1999
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Ingår i: International Journal of Rock Mechanics And Mining Sciences. - 1365-1609 .- 1873-4545. ; 36:5, s. 711-717
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Tidskriftsartikel (refereegranskat)abstract
- In this study, the possible modes of crack initiation and propagation leading to chip formation in rock cutting are studied numerically by using a rock failure process analysis code referred to as RFPA. By using this approach, additional information is obtained on the tool-rock interaction and the failure mechanisms of rock under mechanical tools.
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| 3. |
- Minhat, Mohamad, et al.
(författare)
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A novel open CNC architecture based on STEP-NC data model and IEC 61499 function blocks
- 2009
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Ingår i: Robotics and Computer-Integrated Manufacturing. - : Elsevier BV. - 0736-5845 .- 1879-2537. ; 25:3, s. 560-569
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Tidskriftsartikel (refereegranskat)abstract
- Modern manufacturing industries demand computer numeric controllers, having higher level input languages than outdated G-code, and less proprietary vendor dependencies. IEC 61499 is a new standard for distributed measurement and control systems, that enables portability and interoperability of embedded controllers, along with the ease of their mapping to arbitrary distributed networking hardware configurations. This paper demonstrates that the IEC 61499 reference architecture can be successfully used to create a computer numeric controller, offering interoperability, portability, configurability, and distribution characteristics. The layered CNC-FB architecture is proposed, which simplifies the design of a CNC machine controller with the architecture layers responsible for data processing, data storage and execution. In combination with the object-oriented Model-View-Control design pattern, the CNC-FB architecture supports the design framework, in which simulation of the machining becomes natural and inherent part of the design process, with seamless transition from simulation to actual machining. The implemented controller was tested in both the model and on an actual milling machine
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| 4. |
- Minhat, Mohamad, et al.
(författare)
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STEPNCMillUoA : A CNC system based on STEP-NC and Function Block architecture
- 2009
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Ingår i: International Journal of Mechatronics and Manufacturing Systems. - 1753-1039. ; 2:1-2, s. 3-19
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Tidskriftsartikel (refereegranskat)abstract
- STEPNCMillUoA is the prototype of a new CNC system that utilises the STEP-NC data model and IEC 61499. STEP-NC provides a high-level data model and enables feature-based machining whereas the enabled layered Function Block architecture simplifies the design of the CNC controller. The architecture layers are responsible for data processing, storage and execution. The object-oriented Model-View-Control design pattern supports the system architecture and the design framework, in which simulation of the machining becomes natural and inherent part of the design process, with seamless transition from simulation to actual machining. This system possesses interoperability, portability, re-configurability and distribution characteristics. The system was tested through simulation and actual machining
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| 5. |
- Tang, C. A., et al.
(författare)
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Numerical investigation of particle breakage as applied to mechanical crushing—Part I: Single-particle breakage
- 2001
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Ingår i: International Journal of Rock Mechanics And Mining Sciences. - 1365-1609 .- 1873-4545. ; 38:8, s. 1147-1162
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Tidskriftsartikel (refereegranskat)abstract
- A numerical approach to particle breakage is applied using the Rock Failure Process Analysis code, RFPA (super 2D) . The numerical tool is validated by simulating the Brazilian test with a two-dimensional disk sample. Then two irregularly shaped particles with an exact geometry and exact mechanical properties are numerically modelled to investigate their breakage behaviour under unconfined and confined loading conditions. The numerical results indicate that the dominant mode of failure is catastrophic splitting and progressive crushing, which mainly depends on the loading conditions with respect to confinement. The analysis of the load-displacement curves obtained from the simulations suggests a brittle-ductile transition between the two cases. The lateral constraint increases the initial stiffness and the maximum breakage strength of the particle. Most of the energy released during the failure process comes from the crushing of highly stressed areas, particularly, in the vicinity of the contact points where a crushed zone forms. It is also found that the particle shape governs the breakage strength in addition to the material properties themselves, and that the heterogeneity of the particles governs the fracture propagation paths
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