Convergence Study for Rock Unconfined Compression Test Using Discrete Element Method

Mesh convergence is a vital issue that needs to be addressed in a numerical model. This study investigated the effects of mesh element number on the Discrete Element Method (DEM) to granite rock response under compression loading. This study used the 3D finite-element code LS-DYNA to model the Unconfined Compression Test (UCT) numerical simulation. Models with five different mesh types were conducted for convergence mesh, namely normal mesh, fine mesh, super fine mesh, coarse mesh, and super coarse mesh. The mesh convergence of rock media has been conducted using DEM and steel plates simulated using the Finite Element Method (FEM). The DEM-FEM numerical analysis is compared with the results obtained from the experimental test. The best mesh was obtained as the simulation could reproduce the stress-strain curve trends, the failure behaviour and compression strength observed in the experimental test. The normal mesh was selected as the best mesh type in this study based on the comparisons that have been made. This study shows that the DEM-FEM numerical simulation can represent granite rock and can be used for further study based on mesh convergence

Local calcium carbonate powder: its properties and application as fillers

Calcium carbonate powder used as filler is produced from limestone. It is extremely difficult to define the limits of this mineral category. Its definition depends more on its uses than on its physical or chemical properties. Calcium carbonate filler comes in two forms: ground and light. Ground calcium carbonate is a low quality product and is much cheaper than light calcium carbonate. It has been widely used in several industries. For several purposes. Calcium carbonate filler must have high brightness and vary in size from nominal 325 mesh to submicron material. For plastics and pain industry, they must have low oil absorption and ease of dispersion. Quantitative analysis of the market is difficult to compile due to lack of statistics in the field. However, the polymer and paint industry are the largest consumer of white carbonate filler. Calcium carbonate is essentially a fairly cheap product, despite the fact that sophisticated techniques are used in its production

The measurement of full scale structural beam-column connection deformation using digital close range photogrammetry technique

Measurement and monitoring of structural components such as beams and columns under loading are important in structural analysis and design assessment. Presently, the assessment on structural components on deformation or displacement measurement is carried out through LVDTs or dial gauges. The LVDTs or dial gauges were installed in contact with the structural components, also known as contact method. However, present contact method is subjected to some limitations such as s displacement points of measurement are highly depend on the position of LVDTs available, reliability of LVDTs and dial gauges to measure during the experiments due to possibility of damage sensors and consumption of time on the installation the sensors. Due to the limitations of contact method, this study demonstrates the use of a noncontact method using digital close range photogrammetry technique to measure the deformational behaviour of full-scale structural beams and columns. In this study, a full-scale load tests on structural components were performed under laboratory conditions. A series of digital images of the structural beams and columns under various loads were captured using Nikon DSLR cameras. The digital images then processed and analyzed using digital close range photogrammetric technique to measure and extract the magnitude of the structural beam and column displacements. The deformation and displacement of beam and columns have been validated by comparing the photogrammetric outputs against the results obtained from the LVDTs. The statistical analysis shows the differences obtained between the photogrammetric technique and contact method used were not significant