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Material properties and nondestructive evaluation of laminated veneer lumber (LVL) made from Pinus oocarpa and P. kesiya

SOUZA, Frederico de; MENEZZI, C. H. S. Del; BORTOLETTO JUNIOR, Geraldo
Fonte: SPRINGER Publicador: SPRINGER
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
46.47%
This study aimed at evaluating the mechanical, physical and biological properties of laminated veneer lumber (LVL) made from Pinus oocarpa Schiede ex Schltdl (PO) and Pinus kesiya Royle ex Gordon (PK) and at providing a nondestructive characterization thereof. Four PO and four PK LVL boards from 22 randomly selected 2-mm thickness veneers were produced according to the following characteristics: phenol-formaldehyde (190 g/m(2)), hot-pressing at 150A degrees C for 45 min and 2.8 N/mm(2) of specific pressure. After board production, nondestructive evaluation was conducted, and stress wave velocity (v (0)) and dynamic modulus of elasticity (E (Md) ) were determined. The following mechanical and physical properties were then evaluated: static bending modulus of elasticity (E (M) ), modulus of rupture (f (M) ), compression strength parallel to grain (f (c,0)), shear strength parallel to glue-line (f (v,0)), shear strength perpendicular to glue-line (f (v,90)), thickness swelling (TS), water absorption (WA), and permanent thickness swelling (PTS) for 2, 24, and 96-hour of water immersion. Biological property was also evaluated by measuring the weight loss by Trametes versicolor (Linnaeus ex Fries) Pilat (white-rot) and Gloeophyllum trabeum (Persoon ex Fries.) Murrill (brown-rot). After hot-pressing...

Contribuição ao estabelecimento de parâmetros para ensaios não-destrutivos em madeira serrada por meio de ondas de ultra-som; Contribution to the study of the nondestructive evaluation of timber using ultrasonic technique

Oliveira, Fabiana Goia Rosa de
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 20/06/2005 PT
Relevância na Pesquisa
46.27%
O objetivo deste trabalho foi avaliar a influência do teor de umidade e da dimensão do corpo−de−prova na velocidade de propagação ultra−sônica em madeira serrada. As espécies utilizadas no procedimento experimental foram: cupiúba {Goupia glabra), eucalipto grandis (Eucalyptus grandis), jatobá (Hymenaea spp), eucalipto citriodora (Eucalyptus citriodora), pinus caribea (Pinus caribea var. caribea) e pinus elliottii (Pinus elliottii var. elliottii). Utilizou−se o equipamento de ultra−som Sylvatest, com transdutores exponenciais de 22 kHz. A experimentação para avaliar a influência da dimensão do corpo−de−prova foi feita em duas etapas: variando a seção transversal e mantendo o comprimento da peça constante e a seguir mantendo a seção e variando o comprimento. Na primeira etapa, foram utilizados doze corpos−de−prova com dimensões variando desde 6 cm x 12 cm x 50 cm até 1 cm x 12 cm x 50 cm. Para a análise da influência do comprimento, foram utilizadas doze vigas por espécie com dimensão inicial de 6 cm x 12 cm x 300 cm, avaliadas até o comprimento final de 10 cm. A aplicação da onda ultra−sônica foi feita na direção longitudinal. Foram feitos ensaios destrutivos em vigas e corpos−de−prova para a comparação entre os módulos de elasticidade obtidos nos ensaios estáticos e no ensaio com ultra−som. Na experimentação para avaliar a influência do teor de umidade na velocidade de propagação...

Polymer Matrix-Based Piezoelectric Composite for Structural Health Monitoring

Sakamoto, Walter Katsumi; Higuti, Ricardo Tokio; Crivelini, Evelyn Brazoloto; Nagashima, Haraldo Naoyuki; IEEE
Fonte: Ieee Publicador: Ieee
Tipo: Conferência ou Objeto de Conferência Formato: 295-297
ENG
Relevância na Pesquisa
46.27%
Structural health monitoring (SHM) refers to the procedure of assessing the structure conditions continuously so it is an alternative to conventional nondestructive evaluation (NDE) techniques [1]. With the growing developments in sensor technology acoustic emission (AE) technology has been attracting attention in SHM applications. AE are characterized by waves produced by the sudden internal stress redistribution caused by the changes in the internal structure, such as fatigue, crack growth, corrosion, etc. Piezoelectric materials such as Lead Zirconate Titanate (PZT) ceramic have been widely used as sensor due to its high electromechanical coupling factor and piezoelectric d coefficients. Because of the poor mechanical characteristic and the lack in the formability of the ceramic, polymer matrix-based piezoelectric composites have been studied in the last decade in order to obtain better properties in comparison with a single phase material. In this study a composite film made of polyurethane (PU) and PZT ceramic particles partially recovered with polyaniline (PAni) was characterized and used as sensor for AE detection. Preliminary results indicate that the presence of a semiconductor polymer (PAni) recovering the ceramic particles...

Avaliação de variáveis tecnológicas na produção de painéis LVL confeccionados com paricá (Schizolobium amazonicum Huber ex. Ducke); Evaluation of technological variables to produce LVL from Schizolobium amazonicum Huber ex. Ducke

Melo, Rafael Rodolfo de
Fonte: Universidade de Brasília Publicador: Universidade de Brasília
Tipo: Tese
POR
Relevância na Pesquisa
36.39%
Tese (doutorado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Florestal, 2012.; O trabalho teve como objetivo avaliar variáveis tecnológicas envolvidas no processo de manufatura de painéis LVL produzidos com a madeira de paricá (Schizolobium amazonicum). Para isso foi analisado o rendimento em laminação da espécie, a qualidade das lâminas produzidas e influência dos fatores, espessura das lâminas, método de montagem do painel e tipo de adesivo utilizado, nas propriedades físicas e mecânicas dos painéis. Também foi avaliada a aplicabilidade de diferentes métodos de avaliação não destrutiva para predição das propriedades desses. Foi observado que o paricá apresenta um elevado rendimento em laminação, sendo observado em média um volume aproximado de 59% em lâminas verdes para cada tora laminada. O rendimento em laminação pode ser facilmente estimado por meio de variáveis dendrométricas da tora. As lâminas produzidas apresentaram coloração branco-acinzentada, baixa massa específica (0,32 g/cm3 ) e baixa estabilidade dimensional (coeficiente anisotrópico de 2,94). A utilização de lâminas de menor espessura proporcionou a manufatura de painéis mais resistentes, em contrapartida...

Estudo do comportamento vibro-acústico de materiais compósitos e estruturas sanduíche para aplicações em ensaios não destrutivos; A study on the vibro-acoustic behavior of composite materials and sandwich structures focusing on applications in nondestructive evaluation

Tourinho, André Miazaki da Costa
Fonte: Universidade de Brasília Publicador: Universidade de Brasília
Tipo: Dissertação
POR
Relevância na Pesquisa
46.27%
Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Mecânica, 2013.; O uso de materiais compósitos e estruturas sanduíche vem crescendo com o passar do tempo. Este crescimento gera, por sua vez, uma demanda por formas de se detectar defeitos e danos, e avaliar a integridade de estruturas feitas com esses materiais de maneira prática e confiável. Neste contexto, o presente trabalho busca iniciar o desenvolvimento de novos métodos de ensaio não destrutivo de materiais compósitos e estruturas sanduíche, baseando-se no comportamento vibro-acústico da estrutura. Isto foi feito por duas abordagens distintas: experimental e numérica. Na abordagem experimental, estudou-se a possibilidade de usar parâmetros obtidos com base no som radiado pela estrutura para fazer a identificação de defeitos em uma placa-sandu íche, na qual defeitos foram deliberadamente introduzidos durante a fabricação. Foram testados dois parâmetros psicoacústicos — loudness e sharpness — e o chamado Índice de discrepância. Com estas três métricas foi possível identificar falhas. Contudo, dificuldades como indicações de defeito em locais onde não há nenhum e o tempo de duração do ensaio permanecem como obstáculos a serem vencidos. Na abordagem numérica...

Ensaios não destrutivos para avaliar o desempenho de madeiras amazônicas tratadas quimicamente; Nondestructive tests to evaluate the perfomance of treated amazonian woods

Teles, Ricardo Faustino
Fonte: Universidade de Brasília Publicador: Universidade de Brasília
Tipo: Tese
POR
Relevância na Pesquisa
36.47%
Tese (doutorado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Florestal, 2014.; O presente estudo teve como objetivo avaliar o uso e viabilidade de quatro diferentes técnicas de ensaio não destrutivo em campo de apodrecimento e em ensaios de intemperismo acelerado em laboratório utilizando as madeiras de marupá (Simarouba amara), tauari (Couratari sp.) e cumaru (Dipteryx odorata) sem tratamento químico e tratadas quimicamente com o preservante arseniato de cobre cromatado (CCA) tipo C. Para tanto, as madeiras foram usinadas em amostras no formato de estacas para a exposição em campo de apodrecimento e em réguas retangulares para o ensaio de intemperismo acelerado. O tratamento preservativo foi realizado em autoclave industrial sob pressão com CCA-C por meio do processo Bethell de célula cheia. Os métodos empregados para a avaliação não destrutiva foram a técnica de ondas de tensão, ondas ultrassônicas, colorimetria e análise da superfície pela rugosidade. Foi observado que somente as madeiras de marupá e tauari apresentaram penetração e retenção da solução de CCA-C na porção permeável do cerne, sendo o cumaru não impregnado através do processo Bethell. Embora o tratamento químico com a solução preservante CCA tipo C tenha diminuído a velocidade de propagação das ondas de tensão e ultrassônicas nas madeiras de marupá...

Eficácia do UPV na avaliação não destrutiva de elementos de Castanho; Effectiveness of the UPV on nondestructive evaluation of elements of Chestnut timber

Oliveira, Mário André Ferreira
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Trabalho de Conclusão de Curso
Publicado em //2012 POR
Relevância na Pesquisa
46.35%
Dissertação de mestrado integrado em Engenharia Civil; A madeira é um dos materiais mais antigos utilizados na construção, estando por isso presente numa grande parte das construções históricas existentes. A avaliação das propriedades de uma estrutura em madeira tem por base o recurso a inspeções visuais realizadas in-situ e a ensaios não destrutivos, que têm como objetivo estimar as propriedades mecânicas do material em questão, sem que para isso seja necessário causar qualquer dano relevante à estrutura tratada. Nesta dissertação, é apresentado um estado de arte geral sobre a avaliação não destrutiva da madeira que inclui a discussão de vários estudos já efetuados nesta área do conhecimento. O objetivo geral desta dissertação é a verificação da eficácia dos testes UPV, com diferentes frequências de onda, na avaliação de elementos de Castanho retirados de uma construção existente. Para isso, foram realizadas correlações entre ensaios não destrutivos e ensaios mecânicos, ambos realizados em 22 tábuas de Castanho antigo, com aproximadamente 100 anos, de forma a avaliar a fiabilidade deste ensaio não destrutivo na estimação de parâmetros como a rigidez e a resistência à flexão e a densidade. A campanha de ensaios realizada envolveu os seguintes testes e procedimentos: inspeção visual...

Neutron tomography using projection data obtained by Monte Carlo simulation for nondestructive evaluation

Silva,A. X. da; Crispim,V. R.
Fonte: The Brazilian Society of Mechanical Sciences Publicador: The Brazilian Society of Mechanical Sciences
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/11/2002 EN
Relevância na Pesquisa
46.27%
This work present the application of a computer package for generating of projection data for neutron computerized tomography, and in second part, discusses an application of neutron tomography, using the projection data obtained by Monte Carlo technique, for the detection and localization of light materials such as those containing hydrogen, concealed by heavy materials such as iron and lead. For tomographic reconstructions of the samples simulated use was made of only six equal projection angles distributed between 0º and 180º, with reconstruction making use of an algorithm (ARIEM), based on the principle of maximum entropy. With the neutron tomography it was possible to detect and locate polyethylene and water hidden by lead and iron (with 1cm-thick). Thus, it is demonstrated that thermal neutrons tomography is a viable test method which can provide important interior information about test components, so, extremely useful in routine industrial applications.

Electromagnetic Imaging Methods for Nondestructive Evaluation Applications

Deng, Yiming; Liu, Xin
Fonte: Molecular Diversity Preservation International (MDPI) Publicador: Molecular Diversity Preservation International (MDPI)
Tipo: Artigo de Revista Científica
Publicado em 19/12/2011 EN
Relevância na Pesquisa
46.39%
Electromagnetic nondestructive tests are important and widely used within the field of nondestructive evaluation (NDE). The recent advances in sensing technology, hardware and software development dedicated to imaging and image processing, and material sciences have greatly expanded the application fields, sophisticated the systems design and made the potential of electromagnetic NDE imaging seemingly unlimited. This review provides a comprehensive summary of research works on electromagnetic imaging methods for NDE applications, followed by the summary and discussions on future directions.

An Instrumented Bioreactor for Mechanical Stimulation and Real-Time, Nondestructive Evaluation of Engineered Cartilage Tissue

Popp, Jenni R.; Roberts, Justine J.; Gallagher, Doug V.; Anseth, Kristi S.; Bryant, Stephanie J.; Quinn, Timothy P.
Fonte: American Society of Mechanical Engineers Publicador: American Society of Mechanical Engineers
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
46.56%
Mechanical stimulation is essential for chondrocyte metabolism and cartilage matrix deposition. Traditional methods for evaluating developing tissue in vitro are destructive, time consuming, and expensive. Nondestructive evaluation of engineered tissue is promising for the development of replacement tissues. Here we present a novel instrumented bioreactor for dynamic mechanical stimulation and nondestructive evaluation of tissue mechanical properties and extracellular matrix (ECM) content. The bioreactor is instrumented with a video microscope and load cells in each well to measure tissue stiffness and an ultrasonic transducer for evaluating ECM content. Chondrocyte-laden hydrogel constructs were placed in the bioreactor and subjected to dynamic intermittent compression at 1 Hz and 10% strain for 1 h, twice per day for 7 days. Compressive modulus of the constructs, measured online in the bioreactor and offline on a mechanical testing machine, did not significantly change over time. Deposition of sulfated glycosaminoglycan (sGAG) increased significantly after 7 days, independent of loading. Furthermore, the relative reflection amplitude of the loaded constructs decreased significantly after 7 days, consistent with an increase in sGAG content. This preliminary work with our novel bioreactor demonstrates its capabilities for dynamic culture and nondestructive evaluation.

Multi-Wave and Hybrid Imaging Techniques: A New Direction for Nondestructive Testing and Structural Health Monitoring

Cheng, Yuhua; Deng, Yiming; Cao, Jing; Xiong, Xin; Bai, Libing; Li, Zhaojun
Fonte: Molecular Diversity Preservation International (MDPI) Publicador: Molecular Diversity Preservation International (MDPI)
Tipo: Artigo de Revista Científica
Publicado em 27/11/2013 EN
Relevância na Pesquisa
36.39%
In this article, the state-of-the-art multi-wave and hybrid imaging techniques in the field of nondestructive evaluation and structural health monitoring were comprehensively reviewed. A new direction for assessment and health monitoring of various structures by capitalizing the advantages of those imaging methods was discussed. Although sharing similar system configurations, the imaging physics and principles of multi-wave phenomena and hybrid imaging methods are inherently different. After a brief introduction of nondestructive evaluation (NDE), structure health monitoring (SHM) and their related challenges, several recent advances that have significantly extended imaging methods from laboratory development into practical applications were summarized, followed by conclusions and discussion on future directions.

An Electromagnetic Sensor with a Metamaterial Lens for Nondestructive Evaluation of Composite Materials

Savin, Adriana; Steigmann, Rozina; Bruma, Alina; Šturm, Roman
Fonte: MDPI Publicador: MDPI
Tipo: Artigo de Revista Científica
Publicado em 03/07/2015 EN
Relevância na Pesquisa
46.32%
This paper proposes the study and implementation of a sensor with a metamaterial (MM) lens in electromagnetic nondestructive evaluation (eNDE). Thus, the use of a new type of MM, named Conical Swiss Rolls (CSR) has been proposed. These structures can serve as electromagnetic flux concentrators in the radiofrequency range. As a direct application, plates of composite materials with carbon fibers woven as reinforcement and polyphenylene sulphide as matrix with delaminations due to low energy impacts were examined. The evaluation method is based on the appearance of evanescent modes in the space between carbon fibers when the sample is excited with a transversal magnetic along z axis (TMz) polarized electromagnetic field. The MM lens allows the transmission and intensification of evanescent waves. The characteristics of carbon fibers woven structure became visible and delaminations are clearly emphasized. The flaws can be localized with spatial resolution better than λ/2000.

Ultrasonic nondestructive evaluation and imaging of defects in reinforced cementitious materials

Wang, Ji-yong, 1967-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 156 leaves; 7775811 bytes; 7775571 bytes; application/pdf; application/pdf
ENG
Relevância na Pesquisa
46.27%
Characterization of defect is one of the important objectives of nondestructive evaluation (NDE) for condition assessment of structures. Among many other NDE techniques, ultrasonic methods play a prominent role in the both quantitative and qualitative assessment of discontinuities in reinforced cementitious materials. Due to the heterogeneous nature of concrete, ultrasonic waves are highly scattered and attenuated, leading to the difficulty of concrete inspection using conventional ultrasonic techniques, including those that work well on relatively homogeneous materials such as metals. This thesis presents an advanced method for sizing and imaging of defects in reinforced cementitious materials. A two-dimensional, three-phase composite model of concrete is proposed to study the propagation and interaction behaviors of ultrasonic waves in concrete structures, and to gain a knowledge about wave diffraction with multiple cylindrical obstacles. The response of the modeled concrete structure to an incident ultrasonic pulse input signal (pulsed ultrasonic P-wave) is analytically investigated and simulated. A characteristic profile of the defect sizing as a function of focal depth is formulated via the synthetic focusing technique. A defect sizing parameter...

Nondestructive evaluation and underwater repair of composite structures

Hagan, William L. (William Laurie), III
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 107 leaves
ENG
Relevância na Pesquisa
46.35%
Composite materials are gaining popularity in U.S. Naval applications because of their unparalleled strength, stiffness, and manufacturing simplicity. A better understanding of the structural integrity of these materials has the potential to reduce overdesign, decrease manufacturing cost, and simplify repairs. Though underwater nondestructive evaluation of composites has not been well documented, this thesis illustrates the available technologies for underwater evaluation and repair of laminated composite structures, similar to those currently used in marine applications. Dependent on accuracy and reliability of underwater evaluation, the decision to pursue temporary or permanent repairs may be made based on available information regarding the structural integrity of the effected repairs. Discussion of the environmental effects on composite laminates and their repairs is included to provide insight into the detrimental effects of contaminates such as saltwater and petroleum products. The effect of the environment has a profound impact on the quality of composite repairs using currently available repair materials. Underwater repairs, whether permanent or temporary, are suggested for future U.S. Navy components such as the DDG-1000 composite twisted rudder. Furthermore...

Nondestructive evaluation and underwater repair of composite structures

Hagan, William L.
Fonte: Escola de Pós-Graduação Naval Publicador: Escola de Pós-Graduação Naval
Tipo: Tese de Doutorado
Relevância na Pesquisa
46.35%
CIVINS; Composite materials are gaining popularity in U.S. Naval applications because of their unparalleled strength, stiffness, and manufacturing simplicity. A better understanding of the structural integrity of these materials has the potential to reduce overdesign, decrease manufacturing cost, and simplify repairs. Though underwater nondestructive evaluation of composites has not been well documented, this thesis illustrates the available technologies for underwater evaluation and repair of laminated composite structures, similar to those currently used in marine applications. Dependent on accuracy and reliability of underwater evaluation, the decision to pursue temporary or permanent repairs may be made based on available information regarding the structural integrity of the effected repairs. Discussion of the environmental effects on composite laminates and their repairs is included to provide insight into the detrimental effects of contaminates such as saltwater and petroleum products. The effect of the environment has a profound impact on the quality of composite repairs using currently available repair materials. Underwater repairs, whether permanent or temporary, are suggested for future U.S. Navy components such as the DDG-1000 composite twisted rudder. Furthermore...

Adhesively bonded composite repairs in marine applications and utility model for selection of their nondestructive evaluation

Panagiotidis, Dimitrios
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 124 leaves
ENG
Relevância na Pesquisa
46.27%
During the last half century, the use of composite materials and structures has been increasing within many industries: aerospace, automotive, civil, marine, and railway engineering, wind power generation, and sporting goods, to name a few. There is, however, only a small open literature base concerning adhesively bonded composite repairs, primarily originating from within the aerospace industry. Moreover, little work has been done toward the optimization of repairs on marine composite structures, despite a growing number of such applications. Few decision-making procedures leading to the undertaking of composite repairs have been articulated. Among these, the selection of the most appropriate nondestructive evaluation (NDE) scheme is acknowledged as an important aspect in determining the extent and the type of repair, and ultimately assessing its quality. Such selections of NDE technique(s) currently appear to be largely based upon qualitative engineering judgment, which is likely to lead to long-term sub-optimal remedies. An open literature review of various repair schemes and the parameters that affect their mechanical properties is undertaken, and conclusions on adhesively bonded composite repairs for marine applications are summarized.; (cont.) Particular attention is given to the effects on the repaired composite of the mechanical and geometric properties of the adhesive and patch materials...

Lattice modeling of ultrasonic nondestructive evaluation of attenuating materials

Thomas, Anton F. (Anton Felipe), 1977-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 208 p.
ENG
Relevância na Pesquisa
46.27%
Theoretical predictions of specific strength and specific stiffness of nanocomposites make them attractive replacements for alloys and fiber reinforced composites in future generations of numerous structures. The reliable and safe utilization of nanocomposites will require their periodic characterization with nondestructive evaluation. When subjected to ultrasonic waves, nanocomposites often exhibit attenuation that is an order of magnitude higher than that of carbon fiber reinforced polymeric composites. Thus, an accurate model of ultrasonic wave propagation in nanocomposites as well as several other modem composites must include attenuation. Lattice modeling is a heuristic approach that consists of the discretization of solids into regularly spaced particles interconnected via nearest-neighbor interactions. For example, the mass-spring-lattice model (MSLM), a lattice model for the simulation and visualization of elastic wave propagation, has been used in favor of other finite-difference and finite-element methods due to its straightforward implementation of boundary conditions and relatively inexpensive explicit numerical integration. Its utility notwithstanding, MSLM discretization produces documented, yet previously unresolved and uncharacterized...

Modeling of basic density of wood from Eucalyptus grandis and Eucalyptus urophylla using nondestructive methods

Couto,Allan Motta; Trugilho,Paulo Fernando; Neves,Thiago Andrade; Protásio,Thiago de Paula; Sá,Vânia Aparecida de
Fonte: UFLA - Universidade Federal de Lavras Publicador: UFLA - Universidade Federal de Lavras
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2013 EN
Relevância na Pesquisa
36.53%
The objective of this study was to evaluate the accuracy of nondestructive variables in inferring basic density of wood from Eucalyptus grandis and Eucalyptus urophylla. A total of 27 clones of Eucalyptus urophylla and 22 clones of Eucalyptus grandis were used, sourced from a clonal trial set up in Martinho Campos, Minas Gerais. After evaluation using nondestructive techniques of resistography and pin penetration at a constant pressure (Pilodyn®), individuals were felled and disks were removed from the 2%, 10%, 30%, 50% and 70% portions of the merchantable height section, and also from the portion 1.30 m above ground level. Basic density was determined by the water immersion method. Values of basic density ranged from 0.412 to 0.609 g.cm-3 for clones at age 42 months and from 0.408 to 0.664 g.cm-3 for clones at age 54 months. The clones of Eucalyptus urophylla provided higher values of average basic density in relation to Eucalyptus grandis. The variable 'amplitude' had better correlation with basic density in comparison with pin penetration at a constant pressure. Nondestructive evaluation can be used in mass preselection of genetic materials, prior to subjecting them to a more accurate, reliable evaluation.

Nondestructive evaluation of wood decayed by xylophagous organisms

Weiler,Michael; Missio,André L.; Gatto,Darci A.; Güths,William G.
Fonte: ABM, ABC, ABPol Publicador: ABM, ABC, ABPol
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/10/2013 EN
Relevância na Pesquisa
36.42%
The aim of this study was to investigate the effects of attack by xylophagous organisms on the physicomechanical properties of Araucaria angustifolia wood from the floor of a historic house in Pelotas, Southern Brazil using two nondestructive methods. To achieve this, samples were collected from the floor for visual assessment by photography in metric scale. All the images were exported to CAD software in order to measure the percentage of the sample's surface attack in relation to its total area. Subsequently, nondestructive tests were performed using an ultrasound with two types of transducers. Mechanical properties of the material was measured through static bending tests and these results were compared with the results of nondestructive methods. The nondestructive methods of computerized visual analysis and ultrasound were efficient for quantifying the surface attack and showed a good relationship with the results obtained in static bending tests.

Wavelet-based deconvolution of ultrasonic signals in nondestructive evaluation

Herrera, Roberto Henry; Orozco, Rubén; Rodríguez, Manuel
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 03/02/2012
Relevância na Pesquisa
46.27%
In this paper, the inverse problem of reconstructing reflectivity function of a medium is examined within a blind deconvolution framework. The ultrasound pulse is estimated using higher-order statistics, and Wiener filter is used to obtain the ultrasonic reflectivity function through wavelet-based models. A new approach to the parameter estimation of the inverse filtering step is proposed in the nondestructive evaluation field, which is based on the theory of Fourier-Wavelet regularized deconvolution (ForWaRD). This new approach can be viewed as a solution to the open problem of adaptation of the ForWaRD framework to perform the convolution kernel estimation and deconvolution interdependently. The results indicate stable solutions of the estimated pulse and an improvement in the radio-frequency (RF) signal taking into account its signal-to-noise ratio (SNR) and axial resolution. Simulations and experiments showed that the proposed approach can provide robust and optimal estimates of the reflectivity function.