Department of Mechanical engineering

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End date: 2019Subject: search.filters.subject.Fracture Behaviour

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    Study on mechanical and fracture behaviour of linear low density polyethylene for rotational moulding
    (BITS Pilani, 2015) Ram Kumar, P. L
    Plastics play a central role in today s life. It offers variety of benefits compared to other newlinematerials in various sectors like automobile, construction and packaging etc. There are numerous newlinemethods for processing plastics. These include: blow moulding, injection moulding, rotational newlinemoulding, transfer moulding and thermoforming. Selection of a suitable manufacturing process newlineis one of the key decisions that are faced while designing plastic products. There are some newlinecrucial applications of plastics products such as automobile fuel tanks, body armor and riot newlineshields for military, large solvent drums etc. where mechanical and fracture characterization is of newlinegreat importance. Also there is a wide range of polymeric materials available. Various newlineapplications demand typical processing method and typical polymeric material in order to newlineenhance the quality. Therefore, it is required to investigate optimum process conditions of plastic newlinemanufacturing process, yielding favourable mechanical and fracture properties. Though lightness newlineand simplicity in processing methods of plastics attracted the designers and manufacturers, a newlinecomplete understanding of process, process parameters and effect of process parameters on newlinemechanical and fracture characterization is required to attain high standard products and its newlineperformance. newlineObjective based multiple attribute decision making method is suggested for the selection newlineof plastic manufacturing process. Through this exercise, rotational moulding process is suggested newlineas a process based on important attributes like cycle time, wall thickness, material availability newlineetc. Rotational moulding is a high temperature, low pressure thermoplastic processing method newlinefor producing hollow parts. Among the different polyethylenes, linear low density polyethylene newline(LLDPE) is used in rotational moulding process because of its unique melt flow properties and newlinefavourable processing window.
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    Experimental and computational investigations on fracture behaviour of extra deep drawn steel sheets in general yield regime
    (BITS Pilani, 2013) Chaudhary, Vikas Vinayak
    Sheet metals have wide applications such as pressure vessels, auto components and newlineaircrafts. Sheet forming processes are among the most important processes in manufacturing. newlineParticularly these processes are important in the field of car body and auto components newlinemanufacturing, due to the fact that the tools are very expensive and any failure or redesign newlineprocedure dramatically increases the price of the products. Fracture phenomenon is one of the newlinemain obstacles affecting sheet metal forming as accurate prediction of fracture initiation is newlinedifficult in the forming processes. Numerous efforts are to predict accurate fracture limits of newlinesheet metals by using formability approach. However, even today to prevent crack formation newlineduring forming process is a challenging task. newlineThe phenomena of crack initiation and crack propagation are dealt within the discipline newlineof fracture mechanics. Significant deformation ahead of crack tip plays an important role in newlinecrack initiation and crack propagation process. Extensive deformation ahead of a crack tip region newlinehas emerged a new discipline in fracture mechanics called general yielding fracture mechanics newline(GYFM). newlinePresent study aims to evaluate fracture behaviour of Extra deep drawn (EDD) steel sheets newlineusing fracture mechanics approach to predict fracture limits accurately which will be beneficial newlineto both, sheet metal manufacturer and their industrial users (product manufacturers). Amongst newlinesheet metals, EDD steel sheets are widely used in auto components. There is an increasing newlinedemand in ensuring consistency in quality and avoid wastage of material during forming newlineoperations. Formability approach is being utilized to predict fracture limits (load at crack newlineinitiation and critical forming rate) for so many decades with numerous attempts made in newlineimproving the quality and ensuring the consistency in quality of EDD steel sheets. newlineFracture mechanics approach is suggested to EDD steel sheet manufacturer to build a newlinecomplete framework in which new methodologies of investigations correlatin.