DELAMINATION PREDICTION IN DRILLING OF CFRP COMPOSITES USING ARTIFICIAL NEURAL NETWORK

Carbon fibre reinforced plastic (CFRP) materials play a major role in the applications of aeronautic, aerospace, sporting and transportation industries. Machining is indispensible and hence drilling of CFRP materials is considered in this present study with respect to spindle speed in rpm, drill size in mm and feed in mm/min. Delamination is one of the major defects to be dealt with. The experiments are carried out using computer numerical control machine and the results are applied to an artificial neural network (ANN) for the prediction of delamination factor at the exit plane of the CFRP material. It is found that ANN model predicts the delamination for any given set of machining parameters with a maximum error of 0.81% and a minimum error of 0.03%. Thus an ANN model is highly suitable for the prediction of delamination in CFRP materials

Static and Dynamic Behaviour of Additive Manufactured Multi-Material Honeycomb Structure

The degree to which a vehicle protects its occupants from the effect of accidents and lightweight requirements in the automotive industry has drawn the attention of composite materials, which have high specific stiffness, strength and energy absorbing capability. At present bumper design is made of single material which constrains it to the property of that particular material only. Additive manufacturing is a technique, which paves way for the manufacturing the combination of multiple materials. Among these combinations of materials, the main aim of the multi-material honeycomb structure is to resist the motion after impact and at the same time absorb energy progressively. The present study aims in providing new possibilities for combining multiple properties in a single product and investigating the effect of various design for additive manufacturing applications. From the results of dynamic FEA, a progressive failure is observed in the multi-material honeycomb structure with increased absorption of energy than single material. The force increases with increase in cell wall thickness due to the stiffness of the material and the force increases with decrease in cell wall size for both single and multi-material honeycomb structure. From the results of static FEA and static experimentation, a progressive failure is observed in multi-material honeycomb structure with increased absorption of energy than single material. The force increases with increase in cell wall thickness due to the stiffness of the material and the force increases with decrease in cell wall size for both single and multi-material honeycomb structure. From the static experimentation results of multi-material honeycomb structure the cell wall thickness of 1mm in multi-material the force experienced by cell size of 3.5mm is 82.3% lower than the cell size of 2.5mm. For cell wall thickness of 1mm in multi-material the force experienced by cell size of 3mm is 55.6% lower than the cell size of 2.5mm. For cell wall thickness of 1mm in multi-material the force experienced by cell size of 2.5mm is maximum. For cell wall thickness of 1.5 mm in multi-material the force experienced by cell size of 3.5mm is 77.8% lower than the cell size of 2.5mm. For cell wall thickness of 1.5 mm in multi-material the force experienced by cell size of 3mm is 28% lower than the cell size of 2.5mm. For cell wall thickness of 1.5 mm in multi-material the force experienced by cell size of 2.5mm is maximum. For cell wall thickness of 2 mm in multi-material the force experienced by cell size of 3.5mm is 77.6% lower than the cell size of 2.5mm. For cell wall thickness of 2 mm in multi-material the force experienced by cell size of 3mm is 28.6% lower than the cell size of 2.5mm. For cell wall thickness of 2 mm in multi-material the force experienced by cell size of 2.5mm is maximum. It is evident that the experimental results are in liaise with the theoretical equation where the thickness of the cell wall increases the force or stress induced increases and if the cell size increases the force or stress induced decreases

Effect of tool pin profile on microstructure and tensile properties of friction stir welded dissimilar AA 6061–AA 5086 aluminium alloy joints

Joints between two different grades of aluminium alloys are need of the hour in many light weight military structures. In this investigation, an attempt has been made to join the heat treatable (AA 6061) and non-heat treatable (AA 5086) aluminium alloys by friction stir welding (FSW) process using three different tool pin profiles like straight cylindrical, taper cylindrical and threaded cylindrical. The microstructures of various regions were observed and analyzed by means of optical and scanning electron microscope. The tensile properties and microhardness were evaluated for the welded joint. From this investigation it is founded that the use of threaded pin profile of tool contributes to better flow of materials between two alloys and the generation of defect free stir zone. It also resulted in higher hardness values of 83 HV in the stir zone and higher tensile strength of 169 MPa compared to other two profiles. The increase in hardness is attributed to the formation of fine grains and intermetallics in the stir zone, and in addition, the reduced size of weaker regions, such as TMAZ and HAZ regions, results in higher tensile properties

Experimental investigation on roundness error in friction drilling and mechanical properties of Al/SiCp-MMC composites

Silicon carbide particulate reinforced aluminum (Al/SiCp) Metal Matrix Composites (MMC) is finding increased applications in Industries due to its unique advantages. Holes are to be drilled in many applications for joining and assembly purposes. Friction drilling is a newer non-traditional hole-making chip less process used to make holes in a single step. The manuscript first discusses the mechanical properties such as tensile strength and micro hardness of Al/SiCp-MMC composites, then it discusses the roundness (hole diameter accuracy) errors on dry friction drilled holes. The parameters considered for the experiments are: the composition of work piece, work piece thickness, spindle speed, and feed rate. The results indicated that the increase in the composition of wt% of SiCp particles increases the tensile strength, hardness. The drilling test results indicated that moderate wt% of SiCp gives better results. Higher spindle speeds and higher feed rates increase the roundness error. The highly influential parameter which affects the roundness error is feed rate. Increase in plate thickness also increases the roundness error in drilling of MMC composites

Effect of chloride ion concentration, spraying time and pH values on corrosion behavior of friction stir welded AZ61A magnesium alloy welds in salt fog environments

The present research devoted to the investigation of the corrosion behavior of AZ61A FSW welds in accelerated conditions, including the influence of salt fog environmental parameters such as chloride ion concentration, pH, and duration of exposure. Significant numbers of tests were carried out that make possible to create the regression model (empirical equation) of influence of selected environmental parameters on corrosion rate. The corrosion products were analyzed by SEM and XRD analysis. This research demonstrates the effect of chloride ion concentrations, spraying time and pH values on corrosion rate, and it show the corrosion activity decelerates with the increasing pH value and spraying time respectively. It was found that the increase in chloride ion concentration accelerates the corrosion of AZ61A weldments. The corrosion morphology was predominantly influenced by the distribution of β-phase (e.g. Mg17Al12 intermetallic)

An Investigation on the Interfacial Adhesion between Amine Functionalized Luffa Fiber and Epoxy Resin and Its Effect on Thermal and Mechanical Properties of Their Composites

The objective of this work is to develop a natural fiber-reinforced epoxy composite with enhanced compatibility between resin and the fiber, achieved by amino silane treatment of Luffa fiber. Amine modification on the surface of the Luffa fiber is confirmed by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Composites with different volume fractions (2%, 4%, 6%, and 8%) of amine functionalized/un-functionalized Luffa fiber and epoxy resin are fabricated. The functionalized/un-functionalized Luffa epoxy composites are subjected to various studies such as tensile, flexural, and impact in the area of the effect of amine functionalization of fiber/epoxy composites. Dynamic mechanical analysis and fatigue analysis are carried out to enable a study on the effect of amine functionalization. Variations in thermal stability of the composites are studied using TGA analysis. A maximum tensile strength value of 18.3 MPa is reached for the 6% amine functionalized composite compared to the plain epoxy of 9.4 MPa. The amine functionalized fiber-reinforced composites show improved thermal, mechanical, and morphological properties as a result of improved interaction between the fiber and matrix