Applied Mechanics and Materials Vols. 465-466

Abstract: 3-Dstereoscopic PIV is capable of measuring 3-dimensional velocity components. Itinvolves a very sophisticated routine during setup, calibration, measurementand data processing phases. This paper aims to verify the 3-D stereoscopic PIVmeasurement procedures and to prove that the flow entering thediffuser is a fully developed flow. A diffuser inlet of rectangularcross-section, 130 mm x 50 mm is presently considered. For verification, thevelocities from PIV are compared with the velocities from pitot static probeand theory. The mean velocity obtained using pitot static probe is 2.44 m/s,whereas using PIV is 2.46 m/s. It thus gives the discrepancy of 0.8%. There isalso a good agreement between the mean velocity measured by PIV and theoreticalvalue with the discrepancy of 1.2%. This minor discrepancy is mainly due touncertainties in the experiments such as imperfect matching of coordinatesbetween the probe and laser sheet, unsteadiness of flow, variation in density andless precision in calibration. Basically, the operating procedures of 3-Dstereoscopic PIV have successfully been verified. Nevertheless, the flowentering diffuser is not perfectly developed due to the imperfect joining ductand the abrupt change of inlet cross-section introduced. Therefore, improvementto the existing rig is proposed by means of installing settling chamber withmultiple screens arrangement and contraction cone.

Abstract: Typically from the industry, the decision on when to deploy subsea processing equipment is a big investment decision and quite a number of the operating oil and gas industry are waiting and monitoring the trend from the big players in the industry. There are quite a number of publications on these equipment groups but it has been based on different issues. There is a need to investigate the current trend on the assessment and selection from both the operators and the equipment manufacturers/suppliers perspective. A technology questionnaire survey was designed and administered to experts in this field. The result reveals Risk and RAM analysis as the most used assessment method; also expert systems has gained some level of acceptability in the final selection process. Some of the criterias such as gas volume variation that are considered not critical in the literature are still ranked as critical by the experts. The experts also suggested other important issues that should be taken into consideration for effective selection and assessment.

Abstract: This study applies the finite element method (FEM) to predict maximum forging load and effective strain in internal helical gear forging. Maximum forging load and effective strain are determined for different process parameters, such as modules, number of teeth, and die temperature of the internal helical gear forging, using the FEM. Finally, the prediction of the power requirement for the internal helical gear warm forging is determined. Therefore, the maximum forming force and strain distribution will be prediction for the different parameters of helical gear worm forging.

Abstract: This study applies the finite element method (FEM) in conjunction with an nanoindentation test to predict the loading curve and stress distribution of thin hard coatings. To verify the prediction of FEM simulation for loading and unloading process, the experimental data are compared with the results of current simulation. Loading curve is investigated for different material parameters, such as elastic modulus E, yield stress Y₀ and tangent modulus ET of nanoindentation process, by finite element analysis. The effects of material properties of thin film on the stress distribution for loading and unloading in the nanoindentation are also investigated. Therefore, the loading curve and stress distribution will be prediction for the different material parameters of nanoindentation process.

Abstract: In developing a new method for weld based freeform fabrication, parameter affecting the geometry of single-pass need to be determined as it has great influence on dimensional accuracy and mechanical property of metallic part. In this paper, profile geometry and microstructure of single pass weld bead developed using Gas Metal Arc Welding Cold Metal Transfer (GMAW-CMT) was investigated. Observation on cross sectional weld bead indicates GMAW-CMT has capability to produce free spatter and crack defect weld bead. Profile geometry measurement shows weld bead develop at higher heat input has width size larger than the weld bead develop at lower heat input. Microstructure examination in the substrate reveals formation of columnar dendritic, cellular and planar structure while at buildup layer exhibit equiaxed dendritic structure

Abstract: This paper presents experimental results of object handling motions to evaluate tactile slippage sensation in a multi fingered robot arm with optical three-axis tactile sensors installed on its two hands. The optical three-axis tactile sensor is a type of tactile sensor capable of defining normal and shear forces simultaneously. Shear force distribution is used to define slippage sensation in the robot hand system. Based on tactile slippage analysis, a new control algorithm was proposed. To improve performance during object handling motions, analysis of slippage direction is conducted. The control algorithm is classified into two phases: grasp-move-release and grasp-twist motions. Detailed explanations of the control algorithm based on the existing robot arm control system are presented. The experiment is conducted using a bottle cap, and the results reveal good performance of the proposed control algorithm to accomplish the proposed object handling motions.

Abstract: The paper presents a set of parametric studies performed on a coal pulveriser by means of scale model classifier. In this study, there were two aspect of geometry have been investigated, the number of vanes and the length of vortex finder. This study has been conducted using ANYSY FLUENT 14.0. The study includes the initial classifier model with 12 vanes and 230mm vortex finder length. An experimental result used to validate the Computational Fluid Dynamics (CFD) result. Velocity measurements were taken at different axial locations within the scale model classifier. In conclusion, the two sets of data indicate good agreement and show the utility of CFD as a rating and design tool for coal pulveriser manufacturers. This work also shows that simplified experimental and computational models can be used to assist in the designing of a fully functional coal air classifier.

Abstract: Stress concentration factor for a plate with circular free stress hole subjected to a uniform far field tension in single direction was investigated in this study. The stress concentration level along X and Y axis was determined by the elasticity theoretical method. Finite element analysis using LISA free source software was validated by the elasticity theoretical results. It was found that finite element analysis stress concentration factor results shows similar pattern as theoretical but higher near of the hole. Plain strain analysis with Quad 8 element type showed better results compared to plain stress with Quad 4 element type and plain strain with Quad 4 element type.

Abstract: Mechanical robot has been widely used in environmental monitoring. The robot were apply to the air ducting in the Mechanical Ventilation and Air Conditioning System ( MVAC) to show real view inside the ducting. The aim of the mobile robot is to help reach certain places that cannot afford by human especially in the ducting. This paper highlight the third model of Mechanical Robot Ducting (MerDuct) that has been developed and analyze the result obtains by the MerDuct. Abandoned ducting was selected to gather the visual image by MerDuct using in-situ approach method. The result shows the real condition inside the ducting, and rubbish were found in the ducting. The information gathers by MerDuct start from the beginning to the end of the ducting. The visual image captured will be important for pre and post duct cleaning process. This kind of monitoring also will be the guide for maintenance activity to create safe and clean indoor air to the building occupants and building environment.

Abstract: Composite materials are widely used in aircraft, automotive, marine and railway applications and are exposed to impact loads, in particular low velocity impact. As material properties of composites are affected by strain-rate [, finite element analysis (FEA) by using static properties would not predict their impact behaviour accurately. Thus, the objective of this study was to include strain-rate effects in the simulation of composite laminates under low velocity impact. This was achieved using ABAQUS anisotropic damage model (ADM) by taking account of material properties changes as a function of log strain-rate using user-defined ABAQUS/VUSDFLD subroutine Strain-Rate Dependent ADM (SRD ADM). Results obtained from SRD ADM were validated using simple tensile test done by Okoli [. Subsequently a three-point bending impact event of a simple composite laminate beam by a cylindrical steel impactor was simulated using both the original ABAQUS Static ADM and the user-defined SRD ADM, and compared with experimental impact test results done by [. The results show that reductions in errors of predicted maximum impact reaction force (compared to experimental data) were achieved from 29% using Static ADM to 14% using SRD ADM and from 35% using Static ADM to 15% using SRD ADM respectively for impactor speeds of 2 ms^-1 and 5 ms^-1.