DOI: http://dx.doi.org/10.14741/ijcet/spl.2.2014.10 47 | International Conference on Advances in Mechanical Sciences 2014 Research Article International Journal of Current Engineering and Technology E-ISSN 2277 – 4106, P-ISSN 2347 - 5161 ©2014 INPRESSCO ® , All Rights Reserved Available at http://inpressco.com/category/ijcet Effect of Hydrothermal Ageing on Glass Fibre Reinforced Plastic (GFRP) Composite Laminates exposed to Water and Salt Water P. Sampath Rao Ȧ* , M. Manzoor Husain Ḃ , Perumalla Janaki Ramulu Ċ Ȧ JNT University Hyderabad, Department of Mechanical Engineering, Vijay Rural Engineering College, Nizamabad A.P.INDIA Ḃ Department of Mechanical Engineering, JNT University Hyderabad. A.P.INDIA Ċ Department of Mechanical Engineering, Vardhaman College of Engineering Hyderabad. A.P.INDIA Accepted 02 January 2014, Available online 01 February 2014, Special Issue-2, (February 2014) Abstract Glass fibre reinforced plastic (GFRP) composites are being used in a large number of diverse applications ranging from aerospace to sports equipment. The reinforcement materials are highly hygroscopic; the matrix material provides protection to the reinforcement. When the edges of composite materials parts made of are exposed to environment, water molecules passes along the reinforcement. This leads damage to the interfacial bonding and affects the performance of the composite laminate. It is necessary to perform mechanical and environmental characterization to enhance their application spectrum. There is an imminent need to investigate the mechanical behavior of these materials when subjected to different environmental conditions at different exposure schedules. The aim of the present work is an attempt to provide the investigation procedure to assess influence of moisture absorption on strength degradation coupled with temperature and estimated the life cycle time of polymer composite components. From the results and mathematical analysis, it was clear that the tensile behavior and flexural modulus of the conditioned specimens were significantly reduced due to the environmental impact. Keywords: Glass fibre reinforced polymer; Environmental conditions; Resin transfer molding; Tensile and Flexural modulus. 1. Introduction 1 Polymer matrix composites (PMCs) are increasingly being used in a wide range of applications where long-term service in different environmental conditions. In recent years GFRP/Polyester resin was received considerable attention as alternatives to steel and aluminum due to their high strength-to-weight ratio, competent mechanical properties and ease of handle. Especially in structural materials in the construction, gas and liquid tanks, pipes, offshore platforms, marine, aircraft applications, automotive, recreational equipments and aerospace industries. To study the effects of moisture on retention of mechanical properties of glass fiber reinforced composites during long-term environmental exposure is very crucial which are used for industrial applications. Glass fibre reinforced polymer composites (GFRP) show relatively low degradation in various corrosive environments in the unstressed state, however, they are very susceptible to stress corrosion, especially in dilute mineral acid environment. There are many studies about the effect of environment conditions and exposure times on GFRP composites and other composites. Here, a few important relative studies focused to supporting the *Corresponding author P. Sampath Rao is a Research Scholar; M. Manzoor Husain and Perumalla Janaki Ramulu are working as Prfessor present work. Chin et al. characterized the chemical and physical changes in the polymeric matrix resigns by exposing to different environments like ultraviolet radiation, moisture, temperature, and high pH. They identified the factors that are degrading the matrix resin under varied environmental conditions and mechanical stresses. Straub et al. (1997) conducted a series of experiments by the microbond method to determine the effect of testing rate and temperature on the fiber/matrix interfacial shear strength. Results showed that the interfacial shear strength was found to decrease with the increasing testing rate and the effect was more pronounced below the glass transition temperature. Thwe and Liao (2003 a, b) studied the behavior of composites and hybrid composites of short bamboo and glass fibers in a polypropylene matrix under hygrothermal aging and under tensile–tensile cyclic load. Results suggested that bamboo fiber reinforced polypropylene composite has better fatigue resistance than bamboo-glass fiber reinforced polypropylene hybrid composite at all the tested load levels. Han and Nairn (2003) and Imielinska (2006) also studied the effects hygrothermal ageing of polyimide matrix composites of variable moisture conditions on the fracture toughness of concrete/FRP bonded system are studied by means of the peel and shear fracture toughness determined from the conditioned test specimens. The degradation of the reinforcements played