http://www.revmaterialeplastice.ro MATERIALE PLASTICE ♦54♦No.2 ♦2017 362 Tensile and Bending Analysis of Fabric Reinforced Graded Epoxy Composites MARA DIMOFTE, MARINA BUNEA, ANA CAPATINA, ADRIAN COJAN, RADU BOSOANCA, ADRIAN CIRCIUMARU* Dunarea de Jos University, 47 Domneasc Str. 800008, Galati, Romania Due their various applications the fabric reinforced polymer composites are subject of a large number of researches especially for aero- and automotive industry. Regarding the last domain there are huge interests in designing and forming composites with controllable strengthens for car bodies able to protect both the driver and passengers inside and pedestrians in case of unfortunate events. In this regard, based on previous studies developed at the Research and Development Centre for Thermoset Matrix Composites, our proposal is to design the bending behaviour of a fabric reinforced materials by means of changing the bending strength of the polymer matrix using a solvent. 1-Methyl, 2- pyrrolidinone is a well-known polymer solvent that had been used in previous studies as vector to transfer various organic agents into epoxy resins. During those studies it had been noticed that the presence of above mentioned solvent is changing the bending behaviour of polymer samples and induces some properties that are belonging to memory-shape materials. The present study is related to mechanical analysis of a multi-layered material (fabric layers) immersed into an epoxy resin having a graded bending strength. Keywords: modified epoxy resin, fabrics, bending behaviour, tensile modulus The current industrial orientation toward sustainable development and environment protection leads to an increase in using of alternative sources of energy especially for automotive industry starting with motorization and ending with car bodies. If the motorization is no longer a problem the car bodies are still representing a challenge because they have to fit two general classes of requirements: on one hand the auto vehicles have to be light enough to ensure a suitable ratio between the engine power and the car weight and, on the other hand requirements regarding safety of driver, passengers and pedestrians. Of course, in the case of electric auto vehicles, there are some issues regarding the autonomy i.e. issues regarding batteries recharging but it seems that is solvable by using photovoltaic elements integrated into car bodies. During the last two decades the use of composites was spreading over almost all the industrial applications starting with aero-spatial and ending with sports especially due the fact that their properties are designable from the matrix and immersed elements properties and ending with forming technique. Of course composite elements involves some disadvantages such as difficult (or impossible) reparation and hard neutralization after the life period (waste management for environment protection) but these disadvantages are compensated by major advantages as reduced specific weight, higher strengthens and, of course the fact that a composite part do not need special technologic interventions after formation. The present study was determined by a research project presented at the Sicomp Conference 2015, Composites in Automotive Applications , regarding composites with controllable strength for car bodies applications. Since the main activity of Research and Development Centre for Thermoset Matrix Composites of Dunãrea de Jos University is to design, to form and to test composites, during last decade many research subjects had been purposed especially as doctoral studies and a few as research projects this is why the idea of designing a * email: corresponding author: acirciumaru@ugal.ro material with controllable strength was challenging enough to start a research based on the experience of fabric reinforced composites and diluted epoxy resins. The main principle is to form a material with epoxy matrix and fibre fabric reinforcement but providing the matrix with a gradient of strength. The functional graded composites are not a new subject since they were studied for past decades but generally these materials are regarded as graded at structural level and are seen as applicable for various purposes with a large class of loadings – mechanical, thermal, thermo- mechanical, electromagnetic based on their particular response. In this regard it is about gradation, both on surface layers or on volume and an excellent review of obtaining techniques and properties of such materials is presented in [1]. Many researchers had developed various models to study the properties of functionally graded materials especially for polymer matrix materials [2-14]. Of course many of these studies are punctual but some of them are containing useful information in understanding the way these materials are responding to various loadings in various conditions. As a general tendency regarding fibre reinforced composites the use of carbon fibre might be noticed especially because they are electrical conductors together with their excellent mechanical properties. In this direction the carbon fibre could be used to offer suitable information regarding the state of the material [15-23]. The use of fabrics together with the possibility of changing the basic properties of epoxy systems lead to an opportunity to design the properties of a polymer matrix composite by both alternating various types of fabrics and modifying the properties of matrix at different levels on the depth of the composite plate. Based on previous studies regarding mechanical response of fabric reinforced composites [24-27] and properties of modified epoxy systems [28-31] the actual study is oriented toward analysis