Construction Of Composite Materials Research Articles

Fire decomposition effects on sandwich composite materials

An experimental study was performed to quantify the microscopic changes in composite construction materials to better understand the thermal and structural behavior of sandwich composites during fire. Real-time videos of microscopic response of resin, composite laminates, and balsa wood from an ESEM were used to understand changes in material morphology at elevated temperature. During decomposition of the resin, microscopic pores developed at 180–200°C which is the same temperature range where facesheet debond has been observed in fire tests. This indicates that these pores may serve as crack initiation sites in the debond process. Microscopic changes in materials were linked with the trends in permeability and porosity measured at different levels of decomposition.

Conjugate turbulent natural convection in the roof enclosure of a heavy construction building during winter

This paper presents the results of a study of conjugate turbulent natural convection inside a building attic in the shape of a rectangular enclosure bounded by realistic walls made from composite construction materials under winter day boundary conditions. The effects of cavity aspect ratio, Rayleigh number ( Ra), depth of the external concrete beam, and external wall construction materials on the flow and heat transfer characteristics were the main focus of the investigation. The Shear stress transport k– ω turbulence model is implemented to calculate air-flow velocities and temperatures in a steady, turbulent, two-dimensional conjugate natural convection heat transfer inside an attic. The governing equations were solved by employing the line-by-line tri-diagonal matrix algorithm (TDMA) control volume method. For Ra ranging from 10 7 to 10 10, steady-state results of the streamline and temperature contours in addition to local and mean Nusselt numbers at all surfaces of the cavity were obtained. The results show that the values of Ra, attic aspect ratio and the composite wall materials have significant effect on the temperature and stream function contours within the enclosure, and the heat flux out of the room through the enclosure.

Life-cycle cost assessment model for fiber reinforced polymer bridge deck panels

To enhance the application of fiber reinforced polymer (FRP) bridge deck panels in the infrastructure area, a practical method is required that would allow probable assessment of the life-cycle cost of advanced composite applications in construction compared with that of conventional materials, at various discount rates, while integrating the available reference data. The overall objective of this research is to develop a performance-based probable life-cycle cost assessment model for FRP bridge deck panels. The life-cycle cost assessment model for FRP bridge deck panels comprises a life-cycle performance module (module-1) and a life-cycle cost optimization module (module-2). The model thus developed in this paper can then be used for other applications of composites in construction. The objective of module-1 is to develop an analytical model that is capable of predicting the structural deterioration over time to assess the deterioration rating per year of FRP bridge deck panels. The objective of module-2 is to develop an analytical model that is capable of assessing the optimal life-cycle cost of FRP bridge deck panels. Three case studies were conducted to validate the logic and results of the process algorithm for the life-cycle cost assessment. The model will be very helpful for the construction industry in evaluating various material options and to justify or deny the feasibility of using composite materials on specific construction projects. Since the life-cycle cost assessment of composite materials in construction has not been dealt with as proposed, it is anticipated that many of the procedures and systems mentioned would include fundamental research and possible innovations.Key words: fiber reinforced materials, Monte Carlo method, life-cycle cost, performance valuation.

Influence of Nanotubes and Other Nanofillers on the Properties of Thermoset:thermoplastic Blends for Composite Matrices

ABSTRACTRecently there has been an increase in the use of composite materials for aircraft construction. Composites have significant production and application advantages, but generally suffer from being electrically insulating, and hence are unable to handle a lightening strike in the traditional way that aluminium would. A potential solution to this problem is sought through the use of carbon nanotubes and carbon nanographite. Achieving the correct dispersion of the conducting filler is critical to achieving the desired enhancement in conductivity. Two different methods have been explored to achieve the dispersions; – direct blending and solution dispersion, with a range of concentrations of nanographite being incorporated. In addition, the effect of directly blending graphite nanoplatelets and carbon nanotubes in order to create a hybrid nanocomposite material was studied. The carbon nanotubes were incorporated into a blend with the graphite nanoplatelets with the intention of utilizing their tube structure in order to bridge the gaps between the platelet sheets of nanographite, creating more effective and abundant conductive pathways throughout the composite. In all cases the electrical conductivity was measured using a four point probe technique.

New Composite Construction Material for Low Cost Underground Water Tanks

"ENGINEER", established in 1973 by The Institution of Engineers, is a Journal for dissemination of Engineering knowledge, published quarterly.If you are interested in contributing an Original Technical Paper based on research by the author(s) (intended for Section I) or an Original Article of Professional or Technical interest related to Engineering. (Section II) to this journal please go through the publication checklist which can be downloaded from here.Cover DescriptionCover images show a few views of Stage II of the Central Expressway from Mirigama to Kurunegala. The Institution of Engineers Sri Lanka acknowledges the Road Development Authority (RDA) for the images.

Conjugate natural convection in the roof cavity of heavy construction building during summer

This paper presents the results of a study of conjugate natural convection inside a building attic in the shape of a rectangular enclosure bounded by realistic walls made from composite construction materials under summer day boundary conditions. The effects of cavity aspect ratio, Rayleigh number ( Ra), and orientation of the external surfaces on the flow and heat transfer characteristics were the main focus of the investigation. The problem was formulated in terms of the vorticity-stream function procedure, and the governing equations for steady, laminar, two-dimensional conjugate natural convection heat transfer were solved by employing the Alternating Direction Implicit (ADI) control volume method along with under-relaxation factors for temperature, vorticity, and stream functions. For Ra ranging from 10 3 to 10 10, steady state results of the streamline and temperature contours in addition to local and mean Nusselt number at all surfaces of the cavity were obtained. The results show that the values of Ra and the aspect ratio have significant effect on the temperature and stream function contours within the enclosure. Another important finding of the study is that heat flux into the room increases with the increase of both the aspect ratio and Rayleigh number.

Compression, cleavage, and shear resistance of composite construction materials produced from softwoods and hardwoods

AbstractThe process of manufacturing laminated wood board is an effective technique for reducing or eliminating the negative properties of solid wood materials and for obtaining high‐performance materials. More economical composite laminated materials, which use different types of wood together and have the strength suitable for the purpose, can be produced with this technique. In the present study, composite laminated specimens containing beech (Fagus orientalis Lipsky), a type of hardwood, and poplar (Populus nigra), a softwood, were produced with layers of two thicknesses: 4 and 5 mm. Poly(vinyl acetate) (PVAc) and polyurethane (PU) glues were used in gluing. The results of the tests were compared with those for the solid wood specimens, and it was found that new composite building materials with high mechanical strength and lower cost could be produced for the construction materials sector in Turkey instead of solid wood. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3673–3678, 2006

Development of piping elements from textile reinforced composite materials for chemical apparatus construction

Advancing globalisation in apparatus and plant construction is leading to ever higher demands being made as regards efficiency and performance on the many various components and in this respect on complex piping elements in particular. These construction elements usually need to resist not only the high internal pressures and temperatures, but also the influence of aggressive media. Overcoming the diverse technical demands connected with this can often only be achieved by employing new materials as well as by using corresponding construction techniques and manufacturing technologies. Both a lightweight relevant as well as low cost alternative to conventional metals and the now well-established apparatus construction material of glass fibre-reinforced plastics in wire-wrap technique, form the group of novel textile composite materials, which apart from a very high design flexibility as regards shaping and the load-adapted reinforcing arrangement specifically offer a considerable cost-saving potential. This makes the plastic composite structures with requisite textile reinforcement virtually predestined for cost-effective pipeline systems in chemical apparatus construction with its typical range of construction elements such as T-pipe pieces, angle pieces, reducing pieces or also pipe pieces.

Una nueva fibra de características ideales para su uso en la construcción

The growing use of composite materials in Spanish construction has led in recent years to the materialization of many largescale projects that have revealed the full potential of such systems. Their use has proven to be structurally and aesthetically as well as the economically beneficial, in light of the shipping, assembly and associated maintenance costs. Two specific examples are to be found in the facade on the Reina Sofia Museum in Madrid and a bridge on the Cantabrian Expressway, which are briefly described in this article. The new applications associated with composite materials resulting from the pursuit of ways to capitalize on all their features in turn generate new technological demands that drive the development of yet other new materials. The present article introduces a new fibre that combines mechanical features with excellent long-term performance in combination with concrete.

Development of new cement composite materials for construction

For almost ten years ultra-high performance fibre reinforced concrete (UHPFRC) has been developed throughout the world. After a reviewing and carrying out a critical analysis of the different UHPFRCs which exist, and some prospects related to these materials, a new cementitious composite, patented by the Laboratoire Central des Ponts et Chaussees (LCPC) in France, is presented. This UHPFRC has such good mechanical behaviour in tension that it is possible to construct structures or manufacture structural members without reinforcement in addition to the fibres.

‘RCHX-1-STORM’ first Slovenian meteorological rocket program

Astronautic and Rocket Society Celje (ARSC) formed a special working team for research and development of a small meteorological hail suppression rocket in the 70th. The hail suppression system was established in former Yugoslavia in the late 60th as an attempt to protect important agricultural regions from one of the summer's most vicious storm. In this time Slovenia was a part of Yugoslavia as one of the federal republic with relative high developed agricultural region production. The Rocket program ‘RCHX-STORM’ was a second attempt, for Slovenia indigenously developed in the production of meteorological hail suppression rocket. ARSC has designed a family of small sounding rocket that were based on highly promising hybrid propellant propulsion. Hybrid propulsion was selected for this family because it was offering low cost, save production and operation and simple logistics. Conventional sounding rockets use solid propellant motor for their propulsion. The introduction of hybrid motors has enabled a considerable decrease in overall cost. The transportation handling and storage procedures were greatly simplified due to the fact that a hybrid motor was not considered as explosive matter. A hybrid motor may also be designed to stand a severe environment without resorting to conditioning arrangements. The program started in the late 70th when the team ARSC was integrated in the Research and Development Institute in Celje (RDIC). The development program aimed to produce three types of meteorological rockets with diameters 76, 120 and 160 mm . Development of the RCHX-76 engine and rocket vehicle including flight certification has been undertaken by a joint team comprising of the ARCS, RDIC and the company Cestno podjetje Celje (CPC), Road building company Celje. Many new techniques and methods were used in this program such as computer simulation of external and internal ballistics, composite materials for rocket construction, intensive static testing of models and flight configuration with long flight-testing program. The main features of this project were discussed in this paper, summarizing the history of the development of the RCHX-STORM rockets family.

A Framework for Life-Cycle Cost Assessment of Composites in Construction

The slow acceptance of composite materials in construction could be attributed to the high initial cost of composites compared to conventional materials and the limited information on life-cycle cost. This paper presents a unique framework for a probable life-cycle cost assessment model for composite materials in construction. The proposed model utilizes the historical life-cycle performance data for conventional materials, knowledge about material properties, and deterioration characteristics for new and conventional materials to effectively assess the life-cycle cost and behavior of composite materials in construction. The proposed model integrates deterioration characteristics of structural components under different environmental and loading conditions to establish performance envelopes. Monte Carlo simulation models are generated to evaluate various maintenance, repair, and rehabilitation (MR and R) strategies possible over the life-cycle. The life-cycle cost associated with each scenario is computed, at different discount factors, to obtain the optimum life-cycle cost for various material options. The specifics of the model are illustrated through an example.

Finite Element Simulation of a Full-Scale Crash Test of a Composite Helicopter

Finite Element Simulation of a Full-Scale Crash Test of a Composite Helicopter

A comparison of the mechanical properties in compression of two resin systems

This paper reports on the work carried out on two resins, which served as matrices in glass fibre-reinforced composite structural materials for naval ship construction. In generic terms, these are called polyester and vinylester. Specimens were subjected to compressive strain rates ranging from 0.005 to 10 s −1 using a servo-hydraulic testing machine. Fundamental properties related to resin strength, modulus and ductility were measured, and fracture mechanisms were studied using scanning electron microscopy (SEM) and optical microscopy. The influence of resin properties on the overall performance of short glass fibre composites is discussed.

New lightweight composite construction materials with low thermal conductivity

This paper presents an initial investigation on the use of a new lightweight construction material, composed of cement, sand and fiber of waste from young coconut (Cocos nucifera) and durian (Durio zibethinus). Thermal conductivity, compressive strength and bulk density were investigated. The experimental investigation reveals that the addition of these fibers reduces the thermal conductivity of the composite specimen and yield a lightweight. The composite satisfies the basic requirement of construction materials, and they could be used for walls and roofs. Thus, the potential for development, therefore, seems to be very promising. Finally, apart from saving energy consumption for the building, the proposed materials offer an alternative option to dispose waste of fruit industry.

Structurally reinforced thermoplastic-fabric composite construction materials that are mouldable: Grimnes, M.S. (Brunswick Technologies, Inc., Brunswick, ME, USA) US Pat 4 344 687 (6 September 1994)

Structurally reinforced thermoplastic-fabric composite construction materials that are mouldable: Grimnes, M.S. (Brunswick Technologies, Inc., Brunswick, ME, USA) US Pat 4 344 687 (6 September 1994)

Investigation of the stability of a composite in compression along two parallel structural cracks at the layer interfaces

Composite construction materials with a layered structure may have various imperfections in the interlayer adhesion due to the technology used for their manufacture or their service conditions. In particular, this may involve defects of the crack type. Upon compression along such defects, the classical criteria for fracture (Griffith-Irwin or its generalization) cannot be used, since in this situation all the stress intensity factors and the openings of the sides of the crack are equal to zero, the onset of the process of fracture of the composite upon compression along cracks was hypothesized to be connected with loss of stability (buckling) in the vicinity of the crack. In investigation of the stability of a composite with cracks, different applied calculation schemes have been used by different authors: rod, shell, etc., and also approximate theories such as (for example) continuum theory. And within the framework of the latter, we cannot distinguish between interlayer and intralayer cracks. In this paper, within an exact formulation we consider the stability of a composite in compression along two parallel structural cracks located at the layer interfaces.

Intelligent materials for intelligent structures

A significant amount of development work has been performed on materials with embedded sensory capabilities for civil structures. An excellent candidate is reinforced concrete, a ubiquitous composite construction material. Results from laboratory and field studies concerning the use of fiber-optic sensors embedded in concrete are discussed. The embedded fiber optics can be used in information networks in buildings to carry data on wind loading and structural damage, as well as telecommunications, security, and heating, ventilation, and air-conditioning (HVAC) data. >

‘The first fifty years of composite materials in aircraft construction’

The title of this article may surprise those who look upon composites as a recent innovation. The first major step was taken in 1940 when Dr Norman de Bruyne's Aero Research Ltd of Duxford, now part of the Ciba-Geigy Group, built a Spitfire fuselage in Aerolite, a material developed by them comprising flax thread skeined and impregnated with a phenolic resin and formed in a heated press. The project arose as a safeguard against a possible war-time shortage of aluminium alloys. Tests at RAE proved entirely satisfactory whilst the weight was the same as the metal version, see Figs 1-3.In 1947 Turner Brothers developed a chrysotile asbestos fibre reinforced phenolic resin called Durestos. The wings of the experimental Fairey Delta E10/47 were built from it and were the first primary composite structures to be flown.Since those days immense strides have been made in the use of advanced composites, most modern civil and military aircraft taking advantage of their unique properties.

Ｐｏｌｙｍｅｒｓ ｉｎ Ｃｏｎｃｒｅｔｅ―新しい動向 １ 複合建設材料としてのコンクリート工事用樹脂

Ｐｏｌｙｍｅｒｓ ｉｎ Ｃｏｎｃｒｅｔｅ―新しい動向 １ 複合建設材料としてのコンクリート工事用樹脂