Materials Science Forum Vol. 819

Abstract: The paper discusses the crushing behavior of glass fibre reinforced epoxy (GRE) pipes under hydrothermal ageing condition. This study determines the behavior of the GRE pipes when subjected to different ageing periods and temperatures. Hydrothermal ageing has been found to cause degradation between resin and fibre interface thus causing the reduction in the strength of composite laminates. The pipes were subjected to hydrothermal condition to simulate and precipitate ageing by immersing the pipe samples in water at 80°C for 250, 500, and 1000 hours. Compression tests were carried out using Universal Testing Machine (UTM) for virgin condition and aged samples in accordance with ASTM D695 standard. The maximum force at the initial failure region is observed for each of the conditioned pipes. The results show that the strength of the matrix systems was considerably degraded due to the plasticization of the matrix system.

Abstract: This paper presents the blast loading of small scale soil barrier subjected to surface burst,analysed by using AUTODYN 2D and AUTODYN 3D.Results from the AUTODYN analyses are then compared with published experimental results. Good agreements with published experimental results are obtained for numerical analysis by using AUTODYN 3D for peak pressure at the front part of the barrier. In this case study, AUTODYN 2D numerical analyses provide higher pressure readingsat about 62% and 36% differences as compared with the published experimental results for pressure measurement at the middle front and back of soil barrier surface. The discrepancy of AUTODYN2D results was due to geometric dissimilarity from the actual experimental test. For complex geometries shape of barrier, that involves different shapes and configurations, three dimensional analyses are required to accurately predict the complex reflections and interactions associated with the propagation of the blast wave.

Abstract: Hematite nanoparticles with average particle size of 75.6 and 93.4 nm were produced by mechanical grinding technique using planetary ball mill. The ground hematite were characterized by X-ray diffraction analysis technique, specific surface area analysis (BET), transmission microscope (TEM) and scanning electron microscope (SEM). The effects of different properties of hematite particles used as a catalyst for decolorization of synthetic dye, Remazol Red 3B (RR3B) were investigated. The experimental results show that smaller particle size of 75.6 nm decolourized at the rate of 95.8% within 10 min reaction while larger particle size of 93.4 nm decolorized at the rate of 95.9% within 60 min reaction. The decolorization of RR3B dye by both catalyst were achieved with minimum iron leached (<5 mgL^-1) which fulfill the Malaysian Environmental Quality (Industrial Effluent) Regulations 2009. The continuous mode for decolorization of RR3B was carried out and complete decolorization was achieved with low iron dissolution which demonstrates the possibilities of using milled hematite as catalyst for large-scale textile industry wastewater treatment applications.

Abstract: Ammonia classified as one of the hazardous chemical to environment and human. Therefore, monitoring the ammonia in air is vital. Chitosan film was selected as a sensing material for ammonia detection in this study. Chitosan powder was dissolved in 2% of acetic acid to form chitosan solution gel. It was subsequently deposited on patterned electrode by using electrochemical deposition technique. The response of the chitosan sensor towards ammonia was tested via electrical testing by exposing different ammonia concentration ranging from 20 ppm, 100 ppm, 200 ppm, and 300 ppm using air exposure technique. The response of the chitosan sensor towards ammonia was recorded as output voltage. Sensor properties which include sensitivity, stability, recovery, and repeatability were studied. The electrical result showed that the response of chitosan sensor increases as the ammonia concentration increases. All the sensing properties were achieved. Finally, the structure characterization of the chitosan was studied using Fourier Transform Infrared Spectroscopy (FTIR). The appearance of N-H and O-H groups in FTIR spectrum of chitosan film provides evidence that the domain functional group exist in chitosan after it was processed into film.

Abstract: In this study, an experimental investigation was conducted in order to determine the effect of moisture absorption at different adhesive thickness (i.e., 0.5, 1.0, 1.5 and 2.0 mm) on strength of adhesive T-joint in urea granulator fluidization bed. In particular, T-joint specimens were exposed to three humidity conditions, namely, 80°C, 90°C, and 100°C at a constant time immersion of 15 minutes in water. Stainless steel plate and stainless steel perforated plate were joined by using a specific adhesive jig according to desired thickness. Tensile test was conducted by using universal tensile machine (UTM) at room temperature. The result obtained has enabled to explain the failure mechanisms and characteristics of adhesive T-joint with respect to moisture condition and bonding thickness. Epoxy adhesive with several weight percent of water absorption will degrade the physical properties of the adhesive. Moisture condition has some effect on the strength of the adhesive bonding. 1.0 mm of adhesive thickness provides the highest value of failure load. Experimental results indicated that failure load of adhesive T-joint at room and 90°C water temperature give higher value of strength if compared to water temperature at 80°C and 100°C.

Abstract: This paper presents the results of an experimental investigation on mechanical characterization of adhesive T-joint in granulator fluidization bed at elevated temperature. This research aims to explore the suitability of adhesive bonding between stainless steel plate and perforated plate to replace plug weld in granulator fluidization bed. For this purpose, T-joint and bulk specimens were prepared for tensile loading tests, at different temperature. Measurement of the temperature-dependent of the tensile strength was conducted using thermostatic chamber attached to a universal testing machine for a range from room temperature to 100°C. The strength of adhesive T-joint decreases for temperatures over than 35°C. This is because at high temperature, the failure is determined by the changes of mechanical properties of adhesive. The results have shown that the strength of adhesive T-joint was affected by both temperature and bondline thickness. The objective of the present study was to examine a series of adhesively-bonded T-joints in tension at elevated temperatures between room temperature and 100°C having various bond thicknesses.

Abstract: The improvement of the quality of the surface roughness of the polyurethane board (PB) has always been a challenge in the automotive industry. A suitable combination of the milling parameters is very important in order to get a high grade of smoothness specially when dealing with complex designs such as curved profiles. In this paper, a half factorial design of experiment (DoE) with 16 runs at two levels is applied in the milling operation of the checking fixtures of a car seat belt bracket under a dry cutting condition. The Feed rate, Depth of cut, Spindle speed, Step over and Plunge rate were taken as the variables for the DoE. Two different milling tools, a flat end mill of diameter10 mm for roughing, and a ball nose of diameter 5 mm for the finishing process were used. Minitab software was use to analyze the correlation between the parameters and the surface roughness. The most influential factor in the milling process was observed to be the Step over.

Abstract: A failure characteristic investigation is carried out on a constant forcespring (CFS) (also known as flat spiral spring) fitted in a counterweight balancingmechanism. A SolidWorksSimulation Softwarewas used to performed the static and fatigue test. Based on the simulation results, the maximum Von Mises stress obtained is 455.6 MPa which is less thanthe yield stress, S_y of the material which is520 MPa. The minimum life of the CFS obtained from simulation and analytical fatigue analysis are 4,991cycles and 4,185 cycles respectively. The maximum operating torque applied to the CFS is 62.672 Nmm which corresponds to the position when the CFS is fully deflected. These is much lower than maximum design torque, which is calculated to be 1,335,496.2 Nmm. This shows that the torque applied to the CFS in the counterweight balancing mechanism is acceptable.

Abstract: A failure characteristic of a fractured constant force spring (CFS) or flat spiral spring fitted in a counterweight balancing mechanism is investigated via series of visual experimentation. Macroscopic examination reveals several beach marks that shows direction of fatigue crack propagation has indicated that the CFS fracture had initiated and propagated due to fatigue from an inner surface origin. Macro cracks resulted from stress concentration were also visible on grain boundaries. The crack was initiated at the center of the CFS which later propagated in the direction perpendicular to the applied cyclic load and finally fractured when it can no longer sustain the applied cyclic load. Inspection via Scanning Electron Microscopy (SEM) has indicatedsign of fatigue striations perpendicular to the fracture propagation which is a characteristic of fatigue failure mechanism. Examination of the fractured surface also pointed porosities that reflects points of crack initiation. Multiple crack initiation points identified shows that the fracture was a result of high stress or high stress concentration.

Abstract: A failure analysis of a broken multi strand wire rope from an offshore platform crane was performed. The wire rope was operated for less than 5 years. The wire consists of seven strands, one central strand and six strands around it. The diameter of the small wires was about 0.78-0.94 mm and the larger wires was a round of 1.52 - 1.78 mm. The large size wires were found fractured by cyclic torsional stresses as characterized by the presence of fatigue cracking originating from the outer surface of the wire. Meanwhile the smaller wires were fractured in a ductile manner under excessive load after the larger wire broken out due to the fatigue mechanism.