Stress concentration analysis of plate with circular hole : elasticity theory and finite element comparison

Stress concentration factor for a plate with circular free stress hole subjected to a uniform far field tension in single was investigated in this study. The stress concentration level along X and Y axis was determined by the elasticity theoritical method. Finite element analysis using LISA free source software was validate by the elasticity theoritical 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

Prediction of residual stress using explicit finite element method

This paper presents the residual stress behaviour under various values of friction coefficients and scratching displacement amplitudes. The investigation is based on numerical solution using explicit finite element method in quasi-static condition. Two different aeroengine materials, i.e. Super CMV (Cr-Mo-V) and Titanium alloys (Ti-6Al-4V), are examined. The usage of FEM analysis in plate under normal contact is validated with Hertzian theoretical solution in terms of contact pressure distributions. The residual stress distributions along with normal and shear stresses on elastic and plastic regimes of the materials are studied for a simple cylinder-on-flat contact configuration model subjected to normal loading, scratching and followed by unloading. The investigated friction coefficients are 0.3, 0.6 and 0.9, while scratching displacement amplitudes are 0.05 mm, 0.10 mm and 0.20 mm respectively. It is found that friction coefficient of 0.6 results in higher residual stress for both materials. Meanwhile, the predicted residual stress is proportional to the scratching displacement amplitude, higher displacement amplitude, resulting in higher residual stress. It is found that less residual stress is predicted on Super CMV material compared to Ti-6Al-4V material because of its high yield stress and ultimate strength. Super CMV material with friction coefficient of 0.3 and scratching displacement amplitude of 0.10 mm is recommended to be used in contact engineering applications due to its minimum possibility of fatigue

Mechanical properties of caco3 extracted from cockle shell with high density polyethylene (HDPE) for biomaterials in bone substitute application

This study was conducted to produce CaCO3 powder extracted from cockle shells as bioceramic materials which later combined with high density polyethylene (HDPE) as the polymer to produce composite as the final product. For CaCO3 clarification, the powder form of bioceramics was analyzed using FTIR, SEM and EDX analyses. Then, the composites produced were tested for mechanical properties via tensile and hardness tests. Firstly, the wasted cockle shells were all washed to remove dirts and soaked in regular water overnight before left to dry at room temperature. Then, they were all ground up between range 100 – 200 µm several times until the required size were obtained. The spectrum for FTIR showed identical result as previous work at reading 857.22cm-1 which represent vibrational bonds that can be attributed to the characteristics of external plane bending vibration of carbonate. After the confirmation, it was added to the melted HDPE to produce stronger composite via injection moulding method. Injection moulding process was to produce the sample into the shape of dumbbell to perform mechanical tests, tensile and hardness test with three parameters for each weight ratio. It could be concluded that pressure, velocity and temperature affecting the hardness of samples. In this research, the greatest value of Young’s modulus and maximum force which are 852.2 MPa and 271.457 kN, respectively. In conclusion, cockle shell could become great biomaterial as it provide good in mechanical properties. Furthermore, the source also abundantly available and with the fully usage of this waste to something more useful, it is able to reduce contamination to the earth. Then, the combination with any polymer is able to produce strong composite that could apply in any field. For this research, the composite is focus in biomaterial usage, especially in orthopaedic field for bone implant. For instance, CaCO3 are proved to be function at higher temperature, and further future works might be required to search the maximum temperature that this material could achieve

Experimental evaluation of fish feeder machine controller system

The aim of this project is to apply the automatic fish feeder controller system for fish pellet dispersion machine. The system uses Arduino as a microcontroller which programmed by setting the speed and timer of each DC motor to make this machine functioning automatically. When the adapter is switch, the microcontroller will be connected then activate the motor driver to generate the system. Two motors have been used as motor 1 and motor 2 which functions to drop and disperse the fish pellet respectively. The whole system was programmed through a specific coding and uploaded to the Arduino. This project benefits in reduce the manpower for the fish farming. The component that required to build this project is portable and cost-effective. From experimental result, the timer for motor 1 to dispense the fish food from the storage was 60s while 90s for DC motor 2 as a distributor. The speed for motor 1 was set to 110rpm while motor 2 was set with full speed of 255rpm. The fish pellet can be distributed and scattered up to 5m which can reduce the competition among the fish at one place

Highly Active W-H2SO4/HZSM-5 Catalyst for Direct Conversion of Methane into Aromatic

Dehydroaromatization of methane (DHAM) under non oxidative condition was studied over tungsten loaded HZSM-5 catalysts to produce aromatic hydrocarbons. The catalysts were prepared by impregnation method using different conditions : in neutral and acidified solution. The activity of W/HZSM-5 prepared by neutral solution and W-H2SO4/HZSM-5 prepared in acidified condition were compared. The results showed that the optimum activity of W-H2SO4/HZSM-5 catalyst exceeded that of W/HZSM-5 catalyst. The effect of Si/Al ratio of W-H2SO4/HZSM-5 catalyst was also studied. The W-H2SO4/HZSM-5 catalyst with Si/Al ratio = 30 was found to be the most promising for the DHAM reaction. The remarkable activity of the catalyst is attributed to the presence of dual effects: suitable content of octahedral polymeric and tetrahedral monomeric tungstate species accompanied by proper amount and strength of acid sites in the catalyst

Analysis of Golfer‘s brainwave signal during par tee Ireland and driving range game

Ways to improve sport performance become exceptional contemporary interest. Nowadays, many studies use human brain as an input signal include eyes blinking, attention and meditation to control the exchange process. Brain–Computer Interface (BCI) requires generating control signals for external device by analysing the internal brain signal. The objective is to identify the signal of brainwave which gives effect to performance of golfer. The analysis involved the meditation (α) and attention (β) state of different golf players. In this project, the brainwave of golfer’s will be analyzed based on the movement before club strike the ball. EEG signal used to find out the features by using Fast Fourier Transform (FFT). The analysis included three categories of player include beginner, intermediate and professional. Two types of game have been considered which are Par Tee Ireland and Driving Range. The project interfaces MATLAB software with an EEG headset. The data has interpreted in time and frequency domain graph that show different level in an attention (β) state for both games. Brainwave signals indicated players’ performance and lead to better performance. This data benefits increasing the performance of golfer to become the professional golfer by using electroencephalography (EEG) headset in future study