Juliano Fiorelli

Analysis of the strength and stiffness of timber beams reinforced with carbon fiber and glass fiber

An experimental analysis of pinewood beams (Pinus caribea var hondurensis) reinforced with glass and/or carbon fibers is discussed. The theoretical model employed to calculate the beams bending strength takes into account the timbers ultimate limit states of tensile strength and failure by compression, considering a model of fragile elastic tension and plastic elastic compression. The validity of the theoretical model is confirmed by a comparison of the theoretical and experimental results, while the efficiency of the fiber reinforcement is corroborated by the increased strength and stiffness of the reinforced timber beams.

Sugarcane bagasse and castor oil polyurethane adhesive-based particulate composite

This paper discusses the potential use of sugarcane bagasse in two different fiber lengths (5 mm and 8 mm) of the same density as a raw material for the production of particleboards, using castor oil-based two-component polyurethane adhesive. The quality of the product that can be manufactured industrially was evaluated based on density, thickness swell (TS), absorption (WA), modulus of elasticity (MOE), modulus of rupture (MOR) in static bending and internal bond (IB), according to the Brazilian NBR 14.810:2006 standard. The results revealed a significant difference between the particleboards made with 5-mm-long fibers and those made with 8-mm-long fibers. An analysis by scanning electron microscopy (SEM) indicates that the interparticle spaces are filled with castor oil-based two-component polyurethane adhesive, contributing to improve the physicomechanical properties of the particleboards. A durability assessment based on accelerated aging tests shows that waterproofed particleboards can be used in moist environments.

Extruded Cement Based Composites Reinforced with Sugar Cane Bagasse Fibres

The extrusion process can produce composites with high-density matrix and fibre packing, low permeability and fibre matrix bond strengthening. This process is also compatible with the use of vegetable fibres as raw materials in the production of cost-effective construction elements such as ceiling panels. Sugar cane bagasse fibres (SCF), one of the largest cellulosic agroindustrial by-products of sugar and alcohol industry available in Brazil, are a renewable resource usually used as a biomass fuel for the boilers. The remaining bagasse is still a source of contamination to the environment, so there is a great interest on exploiting novel applications to sugar cane bagasse fibres. In this work, the effect of SCF on extruded cementitious composite performance was evaluated. Three different contents of SCF were considered, using cellulose pulp as secondary micro-reinforcement to improve the resistance to the appearance of microcracks. Composites were prepared using a laboratory Auger extruder with vacuum chamber and were tested after 28 days of water curing and after 200 accelerated ageing cycles. Modulus of rupture (MOR) and Tenacity (TE) of extruded composites were assessed by four point bending test. Water absorption and apparent volume were determined by water immersion. Microstructure behavior was evaluated by mercury intrusion porosimetry and scanning electron microscopy (SEM). Results indicated that the introduction of larger fibres increased tenacity (TE) at 28 days and favored a higher amount of macropores (0.1 to 1 mm); SEM observations confirmed that fibre degradation occurred after 200 cycles.

Influência de diferentes materiais de cobertura no conforto térmico de instalações para frangos de corte no oeste paulista

Este trabalho apresenta um estudo da influencia de diferentes materiais de cobertura no conforto termico de instalacoes destinadas a criacao de frangos de corte. A pesquisa foi desenvolvida no Câmpus Experimental da UNESP de Dracena - SP. Quatro prototipos em escala real foram construidos, com area de 28 m2 cada, cobertos com telha reciclada a base de embalagens longa vida, telha cerâmica, telha cerâmica pintada de branco e telha de fibrocimento. Os dados foram coletados durante o periodo de inverno de 2007, totalizando 90 dias. Com esses dados, foram calculados os indices de conforto termico Carga Termica Radiante (CTR) e a variavel ambiental (Ta). Uma analise estatistica por inferencia e descritiva foi realizada com os valores do indice de conforto termico e da variavel ambiental. Com os resultados obtidos, e possivel afirmar que a telha reciclada apresentou indices de conforto termico semelhantes aqueles encontrados para as telhas cerâmicas. O prototipo coberto com telha de fibrocimento apresentou os maiores indices, e o coberto com telha cerâmica branca, os menores indices de conforto termico. No entanto para o periodo de inverno e para os horarios avaliados, todas as instalacoes apresentaram indices de conforto termico fora da zona de termoneutralidade do frango de corte.

Eficiência térmica de telhas onduladas de fibrocimento aplicadas em abrigos individuais para bezerros expostos ao sol e à sombra

This research presents a study of roof thermal efficiency in individual housing for calves exposed to sun and shade through infrared thermography, internal temperature and thermal comfort indexes. Four different individual housing for calves covered with asbestos-free fiber-cement corrugated sheets were evaluated. Three of them were directly exposed to the sun: (i) corrugated sheets painted white in the external surface, (ii) corrugated sheets without painting and (iii) with screen shade fabric installed 0.10m under de internal surface of the corrugated sheet. The fourth individual housing was installed in the shade area and covered with unpainted corrugated fiber-cement sheets. The analysis was taken for 21 days at 11h00min, 14h00min and 17h00min. The results indicate significant variations in the roofing surface temperature and thermal comfort indexes among the treatments exposed to the sun and shade, for all the evaluations during the day. The infrared thermography images were effective for better understanding the heat transfer processes from the roof to the internal environment of the housing.

Viabilidade técnica de produção e propriedades de painéis de partículas de casca de amendoim

In this study, the potential use of residues of peanut husks was verified, in order to add value to these materials through the manufacture of panels of particleboards. For this procedure, it was used urea- formaldehyde resin and the panels were mechanical pressed at a temperature of 100 oC. The quality of the panels was evaluated based on the prescriptions of the normative document ASTM D 1037:2006, through physical and mechanical tests of characteristics, such as: density, swelling in thickness, water absorption and static bending. The panels evaluated showed bulk density varying between 0,69 a 0,83 g cm -3 , MOR and MOE between 4,37 - 5,34 MPa and 590 - 700 MPa respectively, for panels with and without preservative treatment. It is possible said to claim, based in the normative document ANSI A208.1:1993, that the material presents a potential for use in internal areas as superficial covering of residential buildings, agricultural buildings, furniture and decorative sectors. Intervention in the board production process is recommended, in order to improve the mechanical properties of the material and enable its structural use.

Propriedades mecânicas de peças com dimensões estruturais de Pinus spp: correlação entre resistência à tração e classificação visual

The reduction in the availability the native lumber species and its effects on the economy, associated to the invigoration of the concepts of environmental preservation created the necessity of the development of viable alternatives for rational use of reforestation species. One of the options is the accomplishment of visual grading of the pieces. Research works verified the adaptation of the rules of visual grading of Southern Pine Inspection Bureau (SPIB) of the USA for the Brazilian lumber Pinus, presenting a proposal to normalize the process of visual grading of this lumber. In this classification, the most important aspects are the presence of knots, the inclination of the grain in relation of the axis of the piece and the density of growth rings. Therefore, the current work presents an experimental study consisting of a visual grading and determination of the stress strength of 85 Pinus spp pieces and a theoretical study that presents an equation to establish the average strength strain of structural pieces according to the visual grading. With this work, it was possible to observe the influence of the knots and growth rings in stress strength of the analyzed pieces.

Evaluation of the Effect of Accelerated Carbonation in Cement–Bagasse Panels after Cycles of Wetting and Drying

AbstractThis study aimed to evaluate the effect of the accelerated carbonation curing process as an alternative to preserve sugarcane particles and the physical–mechanical properties of cement–baga...

Potential of the hornification treatment on eucalyptus and pine fibers for fiber-cement applications

In the industry of cement-based products, various lignocellulosic materials are used as reinforcing elements. These cellulosic materials are presented as potential alternatives because of their sustainability, low cost and technical features. However, plant fibers, in spite of good mechanical performance as reinforcement materials, exhibit a number of shortcomings in relation to durability in the alkaline environment of cementitious materials as well as dimensional variation due to their characteristic hygroscopic behavior. Thus, hornification emerges as an alternative, economic and simple pretreatment that is expected to minimize these problems. This study evaluated the physical, chemical and morphological effects of four hornification cycles on pine pulp and innovative eucalyptus pulps, both bleached and unbleached, proving that the treatment does not deteriorate the characteristics of interest of the fibers. Hornification modifies fiber surfaces and reduces their water absorption capacity, turning the pulps into more suitable materials and giving them the technical capability to reinforce brittle inorganic matrices.

Analysis of the Stresses in Corrugated Sheets under Bending

This paper presents three different numerical models for the evaluation of the stresses in corrugated sheets under bending. Regarding the numerical simulations different approaches can be considered, i.e., a elastic linear analysis or a physical nonlinear analysis, that considers criteria to fail for the sheet material. Moreover, the construction of the finite element mesh can be used shell elements or solid elements. The choice of each finite element must be made from the consideration of their representativity before behavior to be simulated. Thus, the numerical modelling in this manuscript was performed from the three-dimensional models using the SAP2000Nonlinear software, version 7.42, which has as base the finite elements method (FEM). It was considered shell elements in the build the mesh of finite elements and an analysis of type elastic linear in this case. Five mm thick sheets were evaluated considering three different longitudinal dimensions (spans), i.e., 1100 mm, 1530 mm and 1830 mm. The applied load to the models was 2500 N/m and it was verified that the spans of support of sheets have a significant influence on the results of stresses. The sheets with larger spans present larger stresses for the same applied load. The most intense values of tension occur in the troughs (low waves) of the sheets, on the lower surface, while the most intense values of compression occur in the crests (high waves), on the upper surface of the sheet. The flanks, which are the parts among the troughs and crests of the sheets, are submitted to low levels of stresses. The numeric results of the stresses showed a good agreement with the results obtained from other researchers 3 and these results can be used to predict the behavior of corrugated sheets under bending.