FRP STRUCTURE DESIGN METHOD BASED ON THE STIFFNESS EQUIVALENCE: CASE STUDY AND PRACTICE
Article history: Received 08.05.2012. Received in revised form 20.07.2012. Accepted 03.09.2012. Nowadays, fiber reinforced polymer materials are getting widely used in civil engineering. They have some advanced engineering characteristics like high stiffness-to-weight ratio, high strength-toweight ratio, anti-electromagnetic interference, electrical isolation and their long term durability. Metal and concrete, two main kinds of construction materials, are prone to failure during their structure service lives because of environmental adverse effects and atmospheric weathering. Those harsh attacks/impacts are oxidization, acidification, high temperature and alkali corrosion. After various maintenance methods like isolating the attacks or protecting plastic skins, an interface crack between protections can easily propagate and cause some durability concern. Fiber reinforced polymer emerges in a new era of civil engineering and can surely be added to traditional materials and/or traditional materials can surely be substituted by this material. This paper sets out to unfold a case study on how fiber reinforced polymer works in civil structures.
Investigation of mechanical properties of bamboo/sisal fiber reinforced hybrid composite materials
Sisal and Bamboo fibers are the most common fibers extracted from natural plants used to fabricate the bio-composite, environmentally friendly products. In this work, the Bamboo-Sisal fibers reinforced epoxy hybrid composite is fabricated to investigate and analyze the compression and hardness properties. The fibers were extracted mechanically and manually from bamboo and sisal plants. The 5% and 8% concentration of sodium hydroxide have been used to treat bamboo and sisal fibers respectively to eliminate lignin, cellulose, and other dirty particles in order to increase interfacial bonding of epoxy to fibers, and performance of the composite. Taguchi experimental approach is used to design composite by considering basic parameters such as weight fraction of sisal, fibers orientation, and curing temperature which affect composite performance. Compression molding and hand lay-up techniques have been used to fabricate the composite. The compression and hardness tests ware predicted on the specimen of hybrid bamboo/sisal fiber reinforced epoxy composites prepared with ASTM standard. The analyzed result revealed that the composite contains a 20/15% volume fraction of sisal to bamboo fibers and fabricated with fiber plies orientation of [0 S /0 B /0 S /0 B /0 S /0 B ] and curing temperature at 40ºC record a high compression strength. While the better hardness strength obtained from composite contain 15/20% volume fraction of sisal to bamboo fibers, and fabricated with fiber plies orientation of [0 S /0 B /0 S /0 B /0 S /0 B ] and cured at 55ºC. as matrix fabricated by hand layup and compression
A New Vacuum Pressure Infiltration CFRP Method and Preparation Experimental Study of Composite
In order to prepare a carbon-fiber-reinforced polymer composite (CFRP) with ideal microstructure and properties, a new vacuum pressure infiltration CFRP method is proposed based on an analysis of existing CFRP preparation process methods. Research on composite material preparation systems was carried out by using this new method principle. The system mainly includes a fiber pre-forming module, a vacuum heating infiltration module, a hot-press curing molding module, and a data acquisition control module. Under the conditions of natural curing at 0 MPa + 6 h + 25 °C, vacuum heating curing at –0.05 MPa + 30 min + 80 °C, and hot-press curing at 0.7 MPa + 5 min + 50 °C, a two-dimensional (2D) CFRP with excellent microstructure and properties was successfully prepared. Observing the microstructure of the prepared composite material, it can be found that the inside of the composite material was sufficiently and uniformly infiltrated, and common preparation defects such as holes and delamination were effectively controlled. Through the performance test, the bending strength of the material reached 790 MPa.