Analysis and Evaluation of Fractur Behaviour of Alluminium Alloy in Various Applications V.Shyamu Mechanical,GURU NANAK INSTITUTIONS TECHNICAL CAMPOUS, Hyderabad India T.Murali Mohan Raju M.V.S.R Engineering College, Hyderabad India S.Sapthagir GURU NANAK INSTITUTIONS TECHNICAL CAMPOUS, Hyderabad India Dr.Alapati Venkateswarlu GURU NANAK INSTITUTIONS TECHNICAL CAMPOUS, Hyderabad India Abstract: In modern materials science, fracture mechanics is an important tool in improving the mechanical performance of mechanical components. It applies the physics of stress and strain, in particular the theories of elasticity and plasticity, to the microscopic crystallographic defects found in real materials in order to predict the macroscopic mechanical failure of bodies. Fractography is widely used with fracture mechanics to understand the causes of failures and also verify the theoretical failure predictions with real life failures. The prediction of crack growth is at the heart of the damage tolerance discipline. Fracture mechanics is the field of mechanics concerned with the study of the propagation of cracks in materials. It uses methods of analytical solid mechanics to calculate the driving force on a crack and those of experimental solid mechanics to characterize the material's resistance to fracture. The central difficulty in designing against fracture in high-strength materials is that the presence of cracks can modify the local stresses to such an extent that the elastic stress analyses done so carefully by the designers are insufficient. When a crack reaches a certain critical length, it can propagate catastrophically through the structure, even though the gross stress is much less than would normally cause yield or failure in a tensile specimen. The term “fracture mechanics” refers to a vital specialization within solid mechanics in which the presence of a crack is assumed, and we wish to find quantitative relations between the crack length, the material’s inherent resistance to crack growth, and the stress at which the crack propagates at high speed to cause structural failure. Key words: Fracture mechanics, Fractography, structural failure, KIc. I. INTRODUCTION In today’s world aluminum and its alloys are the most used metal due to their excellent properties such as recyclability, high strength to weight ratios, high thermal conductivity and good corrosion resistance. As a result aluminum have found a widespread applications in automobile and aerospace industries. High strength aluminum alloys are widely used in aircraft structures due to their high strength-to-weight ratio, machinability and low cost. These are widely used for high strength structural applications such as aircraft wing skins and internal supporting members as well as missile components and automobile industries. II. OBJECTIVES The intend of the paper is to achieve the following 1. It is to gain a basic understanding of the relationship that exist between surface cracks and material toughness. 2. Improved levels of safety in transportation and construction. 3. Anticipating material failure. 4 Designing for material fracture at specific loading conditions. III. TYPICAL PROPERTIES OF ALLOY A. Lightness - With a specific mass of 2700 kg/m3, aluminium is the lightest of all ordinary metals, nearly three times as light as steel. B.Electrical and thermal conductivity - Unalloyed aluminium has a thermal and electric conductivity about 60% of copper, which accounts for its development as a conductor, in the form of bars and tubes C.Corrosion resistance - Aluminium and its alloys provide excellent resistance to atmospheric corrosion in marine, urban and industrial settings. This high resistance extends the life of equipment, significantly reduces International Journal of Innovations in Engineering and Technology (IJIET) Volume 5 Issue 4 August 2015 132 ISSN: 2319 – 1058