Mt1310 Unit 3 Lab Reports

The comparison of measurement and prediction of prestress losses in prestressed members is highly documented in literature. Hale et al. (2006) studied the prestress losses behavior of girders subjected to increased fiber stresses. They concluded that the previous AASHTO LRFD Specifications equations (2004) overestimated the prestress losses by roughly 50%. It was found that the NCHRP Report 496 (Tadros et al., 2003) equations predicted the losses to within an average of 6%. Currently, there have been quite a few investigations on empirical models for prestress losses for HSC. In a study conducted by Kowalsky et al. (2001) on several HPC bridge girders in North Carolina to determine the prestress losses of HPC girders. The researchers found shrinkage losses were a small component of the overall prestress losses and that the elastic shortening and creep losses were the main contributors. These larger than expected losses from elastic shortening and creep were because of a predicted modulus of elasticity that was higher than actual. The total prestress losses ranged from 12.9% to 19.1% of the initial jacking stress. In an investigation conducted by Tadros et al. (2003), seven full-scale bridge girders were instrumented in Washington, Texas, Nebraska and New Hampshire to determine the prestress losses of HPC girders. The total prestress losses measured were found to be lower than the AASHTO LRFD (1998) model. Modified expressions were proposed to AASHTO and later adopted in

Biaxial tensile testing were conducted by means of EnduraTec ELF 3200 (Bose, Minnesota, USA). This mechanical tester has two vertical axes each of which has a 1 kg load-cell (Model 31, Sensotec Honeywell) and a displacement transducer. The apparatus is equipped with a black-and-white CCD-camera video-extensometer (Watec America LCL 902C camera with Computar TEC55 Lens), allowing the automatic tracking of gauge marks, four dots forming a square plotted on the surface of the specimens.

This paper discusses the different properties of composite materials under static testing condition to determine the effect of aging due to change in temperature and moisture content. Effects on tensile, shear, impact, stiffness and fatigue parameters are studied. For each property, application specific composite materials are taken into consideration with different stacking sequence and number of plies. Different samples of these are then introduced to different hygrothermal environments for example: temperatures ranging from -50 degree Celsius to +50 degree Celsius or kept in wet conditions for 24 hours at different temperatures of 21, 37 and 50 degree Celsius etc. Different tests are performed based on the material property to observe a change from the initial unaged specimen. To study every property a different test method is discussed. A final comparison for each property between the unaged and aged specimen is shown in order to see the property’s dependence on temperature and moisture. This comparison highlights the temperature and moisture dependent properties and showcase a trend. Properties like tensile modulus, shear modulus, shear strength, flexural stiffness and fatigue life show a decrease with increase in temperature and moisture content while Poisson’s ratio and impact strength increase with increase in temperature and moisture content.

Design technicians and engineers love to use carbon fibre in manufacturing as it has many desirable properties. First of all is its strength. Carbon fibre is five times stronger than steel and is twice as stiff [2]. The strands of carbon are lined up parallel to each other when producing a sheet. For maximum results in strength, the fibres must be parallel with the forces that will act upon that element, this is to make sure it can withstand the forces going through the object when in use.

Composites, is a material that made with two or more different material. People can see or use it anytime, anywhere. Composite materials can provide different advantages from mixing different materials, and usually combined metal (aluminum), polymers (epoxy) or ceramic (silicon). One of the most common example for the composites will be fishing rod. Nowadays fishing rod usually make with glass fiber/ carbon fiber and epoxy. Which glass fiber or carbon fiber are brittle but strong, and epoxy can provide a high mechanical properties. Result of the fishing rod can be have a better toughness, and lightweight. Because of that in this lab, the main objective is going to use the optical microscopy and find out the fiber’s alignment, the structure pattern and the mechanical properties from the fishing rod.

A composite material is a material that is made of (composed of) 2 or more constituent materials with different physical and chemical properties of each other. When combined, these materials form a composite with different properties from both of its constituent. Composite material is preferred for many reasons. It is often stronger, lighter, and less expensive when compared to traditional materials. Engineered composite materials, for example, are: mortars, concrete, metal composites, reinforced plastics, and ceramic composites. Nowadays, composites are widely used in many fields, especially in industries. Industries including oil and gas industry now use composites as their equipment’s material. One of the strongest reason why composites are now widely used, is that, use of composites lower the production cost for

The objective of composite materials is to take advantage of the superior properties of both materials. Industry has identified the ability of composite material to produce high strength, high corrosive environment, and high durable as well as cost effective products.

Many resins used as matrices for glass fibres allow the spreading of the water, the protection of reinforcing filaments is often not satisfied in many glass reinforced polymers (GRP) and the enviromental damage that occurs is worsened by stress. Loads applied to composite structure are transferred to the fibre materials in the composite, to the load-bearing components, and to the matrix, allowing the composite to resist compression, flexural and shear forces aswell as tensile loads (Harris, 1999).

Aerospace design applications rely heavily on weight reduction, structural integrity and optimize performance. Engineers and designers have adopted carbon fiber composite due to its high modulus reinforcement fibers embedded in an epoxy matrix.

Composite materials are highly resistant to chemicals and do not corrode easily. (Ingenia, n.d.) Hence, reducing the amount of chemicals needed to prevent corrosion. (Airbus, n.d.) Airliners used to face fatigue crack and corrosion with the traditional aluminium floor beams. However, when the Boeing 777 was designed with composite floor beams, not a single floor beam has been replaced till date after flying for more than 10 years. (Boeing, n.d.)

Prediction of failure in composite materials can be done by implementing failure theories [40-44]. The failure criteria’s are not just for

A composite used for tension testing was fabricated by cutting out six same-sized pieces of bi-directional E-glass: two at ± 〖90〗^o and four at ± 〖45〗^o. The pieces were adhered to one another using a wet lay-up with the six pieces of bi-directional E-glass at the following angles in

Wonder composite materials, with a power and universal lightweight relative to weight and hardness properties fell over most of the store of metals and alloys recently. Properties composite depends largely on the characteristics of its constituent materials, the distribution and the interaction between them. In general, filler is the main load bearing Members, while the matrix keeps them in the desired location and orientation, as pregnancy transfer means between the fillers and protects them from environmental damage. The composite characteristics may be part of the total volume of the characteristics of components or the ingredients may interact cooperatively resulting in improved or better properties. Apart from the nature of the constituent materials, engineering promote ( The size and size distribution) affects the properties of composite greatly. Composite structure is a combination of two or more different constituents that can be physically distinguished, resulting in a final product that has better performance than each individual constituent does. Composite materials consist of a matrix (polymer, metal or ceramic) and one or more reinforcing phases (fibers, particles, flakes or fillers). The different constituents are combined judiciously to achieve a system with better structural or functional properties than can be attained by any of the constituents alone. Composites are becoming an essential part of today’s materials due to advantages such as low weight, strong

It has been done the work to describes Flexural strength and flexural modulus of the composites can be successfully improved by filling nonmetals recycled from waste

Abstract: Ever increasing pressure on industry to reduce costs and ecological need of the hour forms the basis of the present research endeavor. Coconut coir is abundantly available in India as a bio-waste. Naturally available coconut fibers in their original form have been used as fillers in glass fiber reinforced epoxy composites. Thrust force being an important parameter in drilling induced damage has been analyzed during drilling of the fabricated composites at four different spindle speeds and three feed rates. Thrust force generally reduced with increase in spindle speed but increased rapidly with feed. Stepped increase in thrust force was observed while analyzing thrust force signals due to geometry of Jodrill.