In the specimens, all showed a brittle fracture due to how the stress vs strain slope looked and where the Ultimate Tensile Strength was located. Also, how the composited specimens failed look consistent that there were any defects in the specimens. The 0°/90° carbon/epoxy specimen failed in the longitudinal direction because of how the fibers were aligned in that direction. The two ±45° glass/ epoxy specimen failed in the 45-degree direction do to how the fibers were aligned in the specimens. These failures would make sense because composites fail when fiber become unconnected so the epoxy failed first and then cause the fibers to fail next. The fibers individual are weak but when are combined and form a pattern with other fibers is how the strength
Dynamic mechanical analysis showed that increasing fiber content provides an improvement in the rigidity of the composites. Cardanol modified resol reinforced nanoclay composite was prepared and mechanical properties of the final composites were improved by doping a 6 wt% of nanoclay in cardanol modified resol (CMR) into the epoxy matrix. The results show that a 15 wt% of CMR in epoxy is a most suitable ratio (Nguyen et al 2007).
However, the absence of plastic deformation does not mean that composites are brittle materials like monolithic ceramics. The heterogeneous nature of composites result in complex failure mechanisms which impart toughness. Fiber-reinforced materials have been found to produce durable, reliable structural components in countless applications. The unique characteristic of composite materials, especially anisotropy, require the use of special design
Linear viscoelastic behaviour of the polymer composite with in the glass transition temperature can be addressed using cole-cole plot. Cole-cole plot is obtained by plotting loss modulus(E”) against
Today's demand for new and properties improved materials are in high. In order to fulfill all those needs people has to go for the Composites. Metal Matrix Composites is the latest trending technology when it comes to the composite materials that posses various improvised properties that suits many property needs. It is also
Composite materials have been evaluated with a matrix properties unsaturated polyester resin by conducting mechanical testing, including the pressure, compression, hardness and impact resistance.. While wood flour helped add to the balance between the original compression strength reductions up to 3 wt. wood flour and then reduce the strength. The results confirmed that the best promote and 3% by weight of wood flour consider the compression strength
Composite structures have been around since the beginning of time, but the modern day uses were first applied during World War II. Composites such as rubber tires and glass were used in structures where metal or other material structures could not be applied. The past few years, composite material structures have been used more in aircraft structures than any other time in the history of man. The main reason is that the understanding and technology are at a point were composite structures could be applied in greater use due to human understanding. Composite structures in aircraft are becoming more practical for more applications. This is based on the how/why composites are being applied, the benefits of composites, the problems/ failures of
The building materials available to engineers today are vastly improved over those of the past. One class which has seen wide spread usage in many fields are composites. These new materials first appeared on the aerospace scene in the early 1970’s, for these materials were found to provide many benefits over the previous metal-based designs.
Polymer Matrix Composites: Most commonly used matrix materials are polymeric. In general the mechanical properties of polymers are inadequate for many structural purposes. In particular their strength and stiffness are low compared to metals and ceramics. These difficulties are overcome by reinforcing other materials with polymers. Secondly the processing of polymer matrix composites need not involve high pressure and doesn’t require high temperature. Also equipments required for manufacturing polymer matrix composites are simpler. For this reason polymer matrix composites developed rapidly and soon became popular for structural
Introduction: The available life cycle cost (LCC) models and procurement strategies do not take into consideration the varied manufacturing techniques for advanced composite materials. The increased use of advanced composite materials in aerospace
In times, metals were replaced by polymers for a few applications like reducing the weight of few parts. But in the present days new classes of engineering plastics are replacing metals at a higher level as they can be customized. Significant productivity improvement is possible by using polymers. There is a higher product performance level, cost reduction, efficiency in manufacturing, durability and enhancement of aesthetics which are all achieved simultaneously now-a-days using
Composite materials and structures are particularly attractive for aerospace applications due to their high stiffness, high strength and low weight properties. The use of such structures allows for an overall aircraft mass reduction, reduced fuel consumption and increased service life resulting in a reduction in aircraft operating costs.
These may be classified into two categories according to the types of reinforcement used: (i) particle or short fibers and (ii) continuous fibers. For continuous fiber reinforced bio-composites, woven fabric preforms processed from natural fibers have been introduced as the reinforcements. Fabrication of laminated composite with four layers of jute woven fabrics has been done. Prior to their impregnation in the resin matrix, the jute fabrics were treated with alkali in the biaxial tensile stress state. A significant improvement of the mechanical stiffness was achieved in the composite with the fibers treated with alkali under applied stress.
Furthermore, flax fiber modulus is comparable to that of glass but has a lower density, this means that flax fibers actually have a higher specific stiffness than glass fibers. The excellent mechanical properties of flax, combined with the added functionalities they bring, make them a very attractive potential material for fiber reinforced composites. Their remarkable advantages compared with those conventional inorganic man-made fillers enhance their commercial and research
Composite materials are defined as the combination of more than two materials, one of the material is called reinforcement material and another one of the material is called matrix, the reinforcement materials in the form of fiber particle, ex; - glass fiber for natural fiber, coconut shell powder matrix material and in the form of resin ex: - phenyl formaldehyde or epoxy, urea formaldehyde and so on.