Attribute Based Selection of Thermoplastic Resin for Vacuum Infusion Process

The composite industry looks toward a new material system (resins) based on thermoplastic polymers for the vacuum infusion process, similar to the infusion process using thermosetting polymers. A large number of thermoplastics are available in the market with a variety of properties suitable for different engineering applications, and few of those are available in a not yet polymerised form suitable for resin infusion. The proper selection of a new resin system among these thermoplastic polymers is a concern for manufactures in the current scenario and a special mathematical tool would be beneficial. In this paper, the authors introduce a new decision making tool for resin selection based on significant attributes. This article provides a broad overview of suitable thermoplastic material systems for vacuum infusion process available in today’s market. An illustrative example—resin selection for vacuum infused of a wind turbine blade—is shown to demonstrate the intricacies involved in the proposed methodology for resin selection.

Material Selection Using a Novel Multiple Attribute Decision Making Method

Selection of a most appropriate material is a very important task in design process of every product. There is a need for simple, systematic, and logical methods or mathematical tools to guide decision makers in considering a number of selection attributes and their interrelations and in making right decisions. This paper proposes a novel multiple attribute decision making (MADM) method for solving the material selection problem. The method considers the objective weights of importance of the attributes as well as the subjective preferences of the decision maker to decide the integrated weights of importance of the attributes. Furthermore, the method uses fuzzy logic to convert the qualitative attributes into the quantitative attributes. Two examples are presented to illustrate the potential of the proposed method.

A Finite Element Study of Buckling and Upsetting Mechanisms in Laser Forming of Plates and Tubes

Laser beam forming has emerged as a viable technique to form sheet metal by thermal residual stresses. Although it has been a subject of many studies, its full industrial application is not yet established. This article aims to complement the existing research in the area of laser forming in order to gain a better understanding of the process. A numerical investigation of laser forming of stainless steel sheets has been carried out and validated experimentally using a High Power Diode Laser (HPDL). Three processing parameters are tested; laser power, beam diameter and plate thickness. Also, laser bending of stainless steel tube is simulated and compared against the published experimental data. The main underlying mechanisms of laser forming are demonstrated through the simulations.

Large Amplitude Forced Vibration Analysis of Stiffened Plates under Harmonic Excitation

Large amplitude forced vibration behaviour of stiffened plates under harmonic excitation is studied numerically incorporating the effect of geometric non-linearity. The forced vibration analysis is carried out in an indirect way in which the dynamic system is assumed to satisfy the force equilibrium condition at peak excitation amplitude. Large amplitude free vibration analysis of the same system is carried out separately to determine the backbone curves. The mathematical formulation is based on energy principles and the set of governing equations for both forced and free vibration problems derived using Hamilton’s principle. Appropriate sets of coordinate functions are formed by following the two dimensional Gram-Schmidt orthogonalization procedure to satisfy the corresponding boundary conditions of the plate. The problem is solved by employing an iterative direct substitution method with an appropriate relaxation technique and when the system becomes computationally stiff, Broyden’s method is used. The results are furnished as frequency response curves along with the backbone curve in the dimensionless amplitude-frequency plane. Three dimensional operational deflection shape (ODS) plots and contour plots are provided in a few cases.

An Investigation into the Environmental Impact of Product Recovery Methods to Support Sustainable Manufacturing within Small and Medium-Sized Enterprises (SMEs)

The effects of climate change and government legislation has changed the way in which manufacturers can dispose of their waste, encouraging SMEs to source alternative disposal methods such as those indicated in the waste hierarchy. It is economically and environmentally beneficial to use product recovery methods to divert waste from landfill. The environmental impact of two product recovery methods, remanufacturing and repairing, has been compared via a carbon footprint calculation for a UK-based SME. The calculation has identified that repairing has a lower carbon footprint than remanufacturing, however this only extends the original life-cycle of the product, whereas remanufacturing provides a new life-cycle and warranty, and therefore seen as the most preferable method of product recovery to support sustainable manufacturing.

Preparation of Copper Oxide (CuO) Nanoparticles and their Bactericidal Activity

Single crystalline nanoparticles of copper oxide (CuO) having almost uniform particle size of ~40±10nm have been synthesized by a facile and versatile route. The technique employed is free from toxic solvents, organics, and amines, and is based on a simple reaction of copper powder and de-ionized water (DI) at very low temperatures of 180oC. The morphology, chemical composition, and crystalline structure of the nanoparticles were carefully investigated by the various characterization techniques. Besides simplicity, the advantages of producing nanoparticles by this method are that it is easeful, flexible, fast, cost effective, and pollution free. The synthesized nanoparticles are under investigations for various applications including their antibacterial activity.

Al2O3 Nanobricks via an Organic Free Route Using Water as Solvent

The chemical synthesis of nanomaterials has been studied by few researchers, but innumerable improvements and better methods have been reported in the past few years. This new approach of preparing aluminum oxide (Al2O3) nanobricks is based on a soft reaction of aluminum powder and de-ionized (DI) water at 200oC without use of any additives or surfactants. Powder X-ray diffraction studies reveal that the as prepared nanobricks are highly crystalline in nature and by morphological investigations using FESEM, it was revealed that the bricks are rectangular in shape having width of 90±15nm and breadth of ~200nm, which was confirmed by high resolution TEM. The technique could be extended and expanded to provide a general, simple, and convenient strategy for the synthesis of nanostructures of other functional materials with important scientific and technological applications. The prospects of the process are bright and promising.

3D Finite Element Modeling of High Speed Machining

This paper presents simulation of High Speed Machining of steel with coated carbide tools. More specifically, Third Wave Systems AdvantEdge commercial Finite Element Method code is employed in order to present turning models, under various machining conditions. As a novelty, the proposed models for High Speed Machining of steel are three-dimensional and are able to provide predictions on cutting forces, tool and workpiece temperatures, chip formation, and chip morphology. Model validation is achieved through experimental work carried out under the same conditions as the ones used in modeling. For the experimental work, the principles for design of experiment were used in order to minimize the required amount of experiments and obtain useful results at the same time. Furthermore, a Taguchi analysis is carried out based on the results. The analysis indicates that there is a good agreement between experiment and modeling, and the proposed models can be further employed for the prediction of a range of machining parameters, under similar conditions.

Laser Sub-Micron Patterning of Rough Surfaces by Micro-Particle Lens Arrays

Laser surface patterning by Contact Particles Lens Arrays (CPLA) has been widely utilized for patterning of smooth surfaces but there is no technique developed by which CPLA can be deposited on a rough surface. For deposition of CPLA, conventional techniques require the surface to be flat, smooth and hydrophilic. In this study, a new method for the deposition of CPLA on a rough surface is proposed and utilized for patterning. In this method, a hexagonal closed pack monolayer of SiO2 spheres was first formed by self-assembly on a flat glass surface. The formed monolayer of particles was picked up by a flexible sticky surface and then placed on the rough surface to be patterned. A Nd:YVO4 laser was used to irradiate the substrate with the laser passing through the sticky plastic and the particles. Experimental investigations have been carried out to determine the properties of the patterns.

Design and Evaluation of Hydro-Pneumatic Friction Damper Suspension System

Perceived comfort level and ride stability are the two most important factors in the evaluation of suspension system in a mobile vehicle. It is extremely difficult to simultaneously maintain a high standard of vehicle ride, handling and body control in the vehicle by using conventional passive suspension system. However, the use of active suspensions would result in better comforts than the passive ones. This paper presents the design and analysis of a pneumatic friction damper and hydro-pneumatic friction damper. A non-linear quarter car model is developed, which includes pneumatic actuation by pressure regulation. The performance of the proposed model was assessed in terms of level of vibration reduction. Simulations on a prototype model show that the proposed system has good performance and robustness.