International Journal of Advanced Engineering Technology E-ISSN 0976-3945 IJAET/Vol.I/ Issue III/Oct.-Dec.,2010/225-231 Research Article EFFECT OF TEMPERATURE ON THE HYGROTHERMAL AND MECHANICAL BEHAVIOR OF GLASS-EPOXY LAMINATES Shivakumar S a , Dr.Shivarudraiah b Address for Correspondence * a Research Scholar, Dept. of Mechanical Engg. UVCE, Bangalore-1 [Asst. Prof, Dept. of I&PE, GIT, Belgaum] b Asst. Professor, Dept. of Mechanical Engg. UVCE, Bangalore-1 [email protected], [email protected]ABSTRACT The aim of the work was to study the effects of temperature on hygrothermal and flexural behavior of glass/epoxy composites exposed for 200 days at different temperature, 30, 50 and 70 °C. The failure mechanisms associated with fractured damage were investigated under three-point bending loading. The flexural moduli, mass uptake, internal laminar shear strength [ILSS] and flexural strength of glass-fiber reinforced epoxy matrix interface weakening and debonding due to different hygrothermal ageing stages have been measured. These results showed that the combined effect of the hygrothermal with the high temperature test, decrease the flexural and ILSS strength of the composite materials but the thickness increased. Micro structural analysis was done for hygrothermally treated samples by Scanning Electron Microscope. KEYWORDS: Hygrothermal Degradation, Flexural Behavior, Epoxy-Glass Laminates INTRODUCTION The fiber reinforced plastics (FRPs), when placed in service, are exposed to a variety of ambient conditions in different types of mechanical loading. The main atmospheric agent causing ambient attacks are the temperature, the relative humidity of air, the effect of ultraviolet radiation, the chemical exposition, the saline water and the contact with hydraulic fuels, gases and fluids. Thermosetting polymeric composites must perform under both environmental conditions combined with deformations and mechanical stresses [1]. Moisture penetration into the composite materials is conducted by one major mechanism, namely, diffusion. This mechanism involves the direct diffusion of water into the matrix and in a much less extent into the fibers. The capillarity mechanism involves the flow of water molecules along the fiber/matrix interface, followed by diffusion from the interface into the bulk resin. Transport of moisture by microcracks and voids involves both flow and storage of water into the microcracks and other forms of micro damages [2]. The strength of the interface determines how much of the applied stress can be transferred to the load-bearing fibers. This strength is largely determined by the contact area between fibers and matrix and the level of adhesion at the contact points. However, it is not clear how the interface should be tailored to optimize composite properties and whether optimum adhesion is desirable or essential to achieve the best balance of mechanical properties [3-5]. The presence of moisture within a FRP can lead to significant changes of the chemical and physical characteristics of the polymeric matrix. Few possible mechanisms have been suggested to
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International Journal of Advanced Engineering Technology E-ISSN 0976-3945
IJAET/Vol.I/ Issue III/Oct.-Dec.,2010/225-231
Research Article
EFFECT OF TEMPERATURE ON THE HYGROTHERMAL
AND MECHANICAL BEHAVIOR OF GLASS-EPOXY
LAMINATES Shivakumar S
a, Dr.Shivarudraiah
b
Address for Correspondence
*aResearch Scholar, Dept. of Mechanical Engg. UVCE, Bangalore-1
[Asst. Prof, Dept. of I&PE, GIT, Belgaum] bAsst. Professor, Dept. of Mechanical Engg. UVCE, Bangalore-1