STRESS ANALYSIS USING FINITE ELEMENT METHOD ON SIALON/AISI 430 FERRITIC STAINLESS STEEL JOINT

Ceramic has many good characteristics for high temperature applications such as in heat exchangers. In the actual application of the ceramic to the structures, a ceramic-to-metal joint is unavoidable. This makes joining of ceramic to metal a critically important technology in advanced engineering. However, the fundamental problem in joining of metals and ceramics is the development of residual stresses which originated from the property mismatch between the ceramic and metal. A finite element analysis (FEA) using ANSYS was used to evaluate the residual stresses in the joints. In this analysis, stress analyses were conducted on sialon/AISI 430 joint. The joint was assumed to be perfectly bonded at the interface at 1200°C and stresses developed during cooling down to room temperature. Sequential coupled-field analysis was performed with PLANE55 and PLANE42. Model was simplified to two dimensional (2-D) problems, since its rotation about the axis of symmetry will generate the complete volume of the cylinder. It was found that the maximum tensile stress occur at the edge of sialon, close to the joint interface. The influence of thickness of sialon, diameter and joint design on the generation of stress in sialon was analyzed. Analyses were made to study the effect of each parameter on stress by varying it, for example, thickness of sialon, while fixing the other parameters. It was found that increasing thickness of sialon and diameter of the joint has resulted in increasing magnitude of tensile stress. The stresses can be reduced by employing symmetrical design joint and incorporating interlayer. The verification of the model was carried out by analytical calculation and comparison with literature review. The results of simulated stresses are in good agreement with the analytical method and literature review

Stress Analysis of Steam-Methane Reformer Tube

Reformer tubes are designed to last at least 100,000 hours (11.4 years) of operation, but frequently, some of the tubes in the furnace fail prematurely. Most of the failures occur due to the high temperature and pressure developed within the tubes. Thus, the use of Finite Element Analysis (FEA) software to model, simulate and draw meaningful conclusion from the actual process conditions of the reformer tubes can reveal important information regarding the mechanical and thermal stress response. The main objective of this project is to simulate the combined stress and temperature profiles developed within the reformer tube. This project involves modeling the mechanical and thermal loadings present in the tube as well as simulating the stress distribution across the tube's thickness and length. FEA using ANSYS utilized to analyze stress and temperature profile of the tube. Literature review of reformer tube has been performed and data needed has been identified. Stresses have been computed using ANSYS and verified with theoretical value. It has been seen that the temperature difference across the tube length resulted from the non-unifonn heat transfer coefficient can be considerable causing high thermal stresses. Maximum von mises stress equal to 142.61 MPa developed at the inner surface of the entrance region. The stress then compared with the tensile strength of the tube and it is showed that the tube is able to sustain the stress without fracture

STRESS ANALYSIS USING FINITE ELEMENT METHOD ON SIALON/AISI 430 FERRITIC STAINLESS STEEL JOINT

Ceramic has many good characteristics for high temperature applications such as in heat exchangers. In the actual application of the ceramic to the structures, a ceramic-to-metal joint is unavoidable. This makes joining of ceramic to metal a critically important technology in advanced engineering. However, the fundamental problem in joining of metals and ceramics is the development of residual stresses which originated from the property mismatch between the ceramic and metal. A finite element analysis (FEA) using ANSYS was used to evaluate the residual stresses in the joints. In this analysis, stress analyses were conducted on sialon/AISI 430 joint. The joint was assumed to be perfectly bonded at the interface at 1200°C and stresses developed during cooling down to room temperature. Sequential coupled-field analysis was performed with PLANE55 and PLANE42. Model was simplified to two dimensional (2-D) problems, since its rotation about the axis of symmetry will generate the complete volume of the cylinder. It was found that the maximum tensile stress occur at the edge of sialon, close to the joint interface. The influence of thickness of sialon, diameter and joint design on the generation of stress in sialon was analyzed. Analyses were made to study the effect of each parameter on stress by varying it, for example, thickness of sialon, while fixing the other parameters. It was found that increasing thickness of sialon and diameter of the joint has resulted in increasing magnitude of tensile stress. The stresses can be reduced by employing symmetrical design joint and incorporating interlayer. The verification of the model was carried out by analytical calculation and comparison with literature review. The results of simulated stresses are in good agreement with the analytical method and literature review

Effect of chemical treatment on the tensile properties of single oil palm empty fruit bunch (OPEFB) fibre

A study on effect of chemical treatment on the tensile modulus and strength of single oil palm empty fruit bunch (OPEFB) fibre is presented in this paper. The fibres were treated with alkaline treatment using sodium hydroxide of 5% concentration. Tensile test were conducted in accordance to the ASTM C1557. Results revealed that the tensile modulus of the treated fibres decreases by around 55% as compared to the untreated fibres. Tensile strength on the other hand increases by around 25% with the alkaline treatment. The tensile strength was found to be dependent on the fibre diameter where the strength decreases with the increases in fiber diameter at fracture. SEM revealed higher porosity at larger fibre diameter which contributed to the degradation of the fibre tensile strength. No significant impact by the alkaline treatment was observed to the tensile strain of the fibre

Crystal structure and Hirshfeld surface analysis of (E)-3-(2-chloro-6-fluorophenyl)-1-(3-fluoro-4- methoxyphenyl) prop-2-en-1-one

In the title chalcone derivative, C16H11ClF2O2, the enone group adopts an E conformation. The dihedral angle between the benzene rings is 0.47 (9)° and an intra­molecular C-H...F hydrogen bond closes an S(6) ring. In the crystal, mol­ecules are linked into a three-dimensional network by C-H...O hydrogen bonds and aromatic [pi]-[pi] stacking inter­actions are also observed [centroid-centroid separation = 3.5629 (18) Å]. The inter­molecular inter­actions in the crystal structure were qu­anti­fied and analysed using Hirshfeld surface analysis

VoVo: a hybrid requirements prioritization technique in scrum-agile environment

Requirements prioritization is a crucial process in Requirements Engineering. However, selecting an appropriate technique in Scrum-Agile environment which can satisfy a quality factor such as scalability, effectiveness and efficiency can be difficult. Moreover, it becomes much more difficult if the stakeholders are distributed in different places and most of stakeholders tend to neglect this activity. This paper will proposed VoVo technique, a hybrid requirements prioritization technique which combined cumulative voting and Volere techniques. VoVo offers a structurally guided prioritization technique which can encourage user participation in prioritization process and also can mitigating the scalability issues especially in geographically distributed project. This hybrid technique is using two tiers prioritization process where in the first tier, the prioritization will be done by stakeholders while in the second tier requirementss will be prioritized by an experts usually a scrum master or project manager. The implemented VoVo has been evaluated through evaluation survey which addressed directly to scrum practitioners. Its suitability and effectiveness in managing and prioritizing requirements in Sprint Backlog will be measured based on testing and evaluation survey feedbacks. Hence, we conclude that VoVo technique is suitable to be used for managing and prioritizing requirements in Scrum project

Design and Fabrication of a Mutual Control Electronic Circuit for Solar and Electrical Water Heating

This research is a temperature controller that will be implemented to ensure that the water temperature of the solar water heating unit is maintained at the desirable level at all times of use. This control circuit is designed to control the On/Off action of the immersed electrical heater according to specific temperature range. A temperature sensor will sense the water temperature constantly and send signal to a micro-controller unit. The micro-controller will process the data according to a written program and control the actions of electrical heater. At the same time, temperature reading will be displayed through LCD and real-time data can be viewed from a computer via serial port. During times of sufficient sunlight, solar energy will be the main source used for heating water; otherwise, there will be an automatic switching to the electrical operated immersion heater. This controller will give reliability to users of solar water heating systems

Mechanical and crash performance of unidirectional oil palm empty fruit bunch fibre-reinforced polypropylene composite

The mechanical properties of unidirectional oil palm empty fruit bunch (OPEFB) fibre / polypropylene (PP) composites were analysed. The composites were fabricated with unidirectional fibre orientations of 0°, 45°,and 90°,with mass fractions of 25%, 35%,and 45% for each fibre orientation angle. The composites were then subjected to tensile, flexural,and impact testing. Superior tensile, flexural,and impact strengths were observed for the unidirectional composites with 0° fibre orientation angle. A fibre loading of 35% provided the highest tensile strength,while fibre loadings of 25% and 45% yielded the greatest flexural and impact resistances, respectively.The crash performance of the unidirectional composite subjected to low-velocity impact in the automotive bumper fascia was investigated. The composite exhibited significantly improved energy absorption capability and comparable specific energy absorption when compared with the current material being used for the bumper fascia

Design and performance of a power generating manual treadmill

Treadmills are one of the most popular training equipment in the gym and at home. The working principle of treadmills is by moving the belt with the human knee bending, which creates mechanical energy to turn the belt. A gear or pulley and belt system connects to the generator along the axel line of the rolling bars. The power generated by the DC generator is stored in a battery pack and could be used to charge phones or other equipment. It has been found that treadmills can provide an efficiency of 95% when the DC motor is used and 92% when the AC motor is used. The main objective of this study is to design and fabricate a powder-generating manual treadmill and to analyze the performance of the system under different operation conditions