In this thesis, two-dimensional floating structure consists of single rectangular impermeable pontoon and single cable is studied.The purpose of this study is to obtain the motion analysis of incident waves acting on a floating with cable-restrained. All boundary conditions are linearlized in the problem which is separated into a scattering problem and radiation problem with unit motion amplitude. The method of separation of variable is used to solve for velocity potentials. Divide two kinds of discussions in cable-restrained¡G1¡BWith sag effective and flexural rigidity. 2¡BNO sag effective and no flexural rigidity. The boundary value problem with nonhomogeneous boundary condition beneath the structure is solved by using a solution procedure proposed by Lee(1995). By combining the scattering solution, radiation solutions of three degrees of freedom, and equations of motion of the floating structure, an analytic solution for the problem is developed.

Ferrocement is often believed to be a form of reinforced concrete. However, in spite of the similarities between the two materials there are still major differences, indicating that ferrocement requires a separate study to establish its structural performances. On the other hand, although a large amount of research has been carried out on ferrocement, its flexural behaviour is still not fully understood. The aim of this investigation is to study the structural behaviour of ferrocement plates under flexural loading and the influence of the different variables on the strength and deformation characteristics. The variables studied were the mesh number, strength, opening and distribution, presence of steel bars, and the thickness of the section and the mortar cover. The experimental programme included 49 plates, 1000x300 mm in dimensions, reinforced with woven type steel wire mesh and tested under two lines load. Deformation measurements were taken from first application of the load up till failure and about10000 crack measurements (crack width and spacing) were recorded. The crack width data were dealt with statistically. The effect of the variables on the crack width was studied, quantitatively, by comparing the rate of growth of crack width of the plates. It was found that ferrocement cracking behaviour is characterized by almost a full development of the cracks at relatively early stages of the load (about 30-50% of the ultimate load) and the crack width is smaller and more uniformly distributed than in reinforced concrete. The mesh number and yield strength influenced significantly the crack width and spacing. There was a limit for the mesh number after which the enhancement in the cracking performance of the plates slowed down noticeably. Crack width prediction equations were derived from these tests showed good correlation, whereas the published crack width formulae largely overestimated or underestimated the measured crack width. The strength and deformation were influenced mainly by the yield strength and fraction volume of reinforcement in the loading direction. The deflection is most likely to exceed the serviceability criteria before the crack width. For a span-deflection ratio of 180, the mean crack width was mostly below 20 microns, and the load was about 15-30% of the ultimate load. A procedure is proposed to analyse ferrocement sections under flexural loading. While application of reinforced concrete theory to predict the ultimate moment largely underestimated the experimental results, the proposed procedure predicted closely the experimental moment and deflection at first cracking, yielding and failure of the tested plates.

In this paper¡Athe cable structures considering sag effect and flexural rigidity are used to the series of dynamic analysis.It dedatees on vibration of the cables by the harmonic force and win¡Ðrain induced vibration. Using the finite element method to analyze the effect of the sge and the effect of the sag and the flexural rigidity¡Aincluding frequencies of the cable and displacement of every nodes at arbitrarily time.

Background: New dental restorative material, “Cention Forte” and “Admira Fusion” have been available on the market for quite some time but are still new in comparison with traditional resin-based composite, “Ceram.x Spectra ST” and glass ionomer cement, “GC Fuji II LC”.  Aim: To compare the flexural strength, elemental composition, and porosity of new dental restorative materials (Cention Forte, Admira Fusion) with existing ones (Ceram.x Spectra ST, GC Fuji II LC).   Methods: Three-point bending test and scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) analysis was used to compare the flexural strength and composition among Cention Forte, Ceram.x Spectra ST, GC Fuji II LC and Admira Fusion. 10 test specimens were used for each material, 40 in total. The dimension of the test specimens were l (25 ± 2) mm x b (2,0 ± 0,1) mm x h (2,0 ± 0,1) mm. The statical analysis was performed with one-way ANOVA followed by Bonferroni’s post-hoc test.  Results: The three-point bending test showed that Cention Forte and Ceram.x Spectra ST had the highest mean flexural strength between the 4 materials tested, whereas GC Fuji II LC had the lowest. Admira Fusion had an intermediate value. SEM-EDS showed significant differences in material density and composition, it was seen that Ceram.x Spectra ST and Admira Fusion had the lowest porosity while GC Fuji II LC had the highest porosity.  Conclusion: It can be concluded that Cention Forte and Ceram.x Spectra ST are the strongest dental materials among the ones tested, with high flexural strength values. Therefore, they may be more suitable for use in high stress-bearing areas. GC Fuji II LC showed the lowest flexural strength values, making it less suitable for use in such areas. Admira Fusion showed intermediate values, making it a good option for applications with moderate stress-bearing requirements. SEM-EDS analysis showed that Ceram.x Spectra ST and Admira Fusion had the lowest amount of porosity, whereas GC Fuji II LC had the highest. The presence of these porosities weakens the material, a higher number of porosities implies lower flexural strength values.

Lapped joints of cold-formed steel (CFS) Z-shaped purlins are extensively used in metal building roof systems. The research that has been carried out so far for these lapped connections is primarily focused on connections with round holes. However, the lapped connections with vertical slotted holes are extensively used in current construction practice to simplify the erection of continuous Z-shaped roof purlins. There is no design guideline or recommendation available for CFS Z-purlin lapped connections with vertical slotted holes. Presented in this paper are the results of an experimental study and analysis of the structural behaviour of lapped CFS Z-shaped purlin connections with vertical slotted holes. 42 flexural tests were performed on lapped CFS Z-shaped purlins with vertical slotted connections with different lap lengths, purlin depths, thicknesses and spans. The flexural strength and deflection of each specimen were measured. The characteristics of moment resistance and flexure stiffness of the lapped purlins were computed. The test results show that the lapped purlins with vertical slotted holes may be more flexible than the lapped purlins with round holes or continuous purlins without lapped joint. Thus, the slotted connections may need greater lap lengths to achieve full stiffness of continuous purlins. The results also indicate that the characteristics of moment resistance and flexural stiffness in the slotted connections are dependent on the ratio of lap length to purlin depth, the ratio of lap length to purlin thickness, the ratio of purlin depth to purlin thickness, and the ratio of lap length to span. Based on the results, design recommendations for evaluating the moment resistance and flexural stiffness of lapped slotted connections were proposed.

Pultruded, fibre reinforced, polymeric composites are now being used in a wide range of structural engineering applications, due to their high strength to weight ratios and resistance to environmental conditions. However, such materials posses a relatively low shear modulus in relation to their axial and flexural moduli. This can result in shear deformation constituting a significant proportion of the total deformation and a reduction in buckling loads for various modes of instability. An experimental and theoretical study of the influence of shear deformation on the flexural and torsional stiffnesses and various modes of instability of pultruded polymeric bars of open cross-section is therefore presented. Theories for the bending and warping torsional response of pultruded, fibre reinforced polymeric bars of open cross-section, excluding and including the influence of shear deformation, are presented. Full section bending mechanical properties of several pultruded beams are determined using a static testing apparatus and a wide variety of span configurations. Full section warping torsional mechanical properties of several pultruded bars are determined using a new testing apparatus, capable of applying a torque to any cross-section along a bar, whilst maintaining the bars lateral position. Theories for the flexural, torsional and lateral instability of pultruded, fibre reinforced polymeric bars of open cross-section, excluding and including the influence of shear deformation, are developed and presented. Parametric studies of the influence of shear deformation in the flexural, torsional and lateral instability of various pultruded bars of open cross-section are also presented. The experimental and theoretical studies indicate that shear deformation reduces significantly the non-uniform bending stiffness of pultruded polymeric bars, but that its influence on the non-uniform and restrained warping torsional stiffness is practically negligible. Shear deformation has also been found to result in a significant reduction in flexural, torsional and coupled flexural-torsional or lateral buckling loads.

Flexural mechanism design is one of the latest field for mechanism researches in these recent years. In this paper, it will address one method of normalized dimensional parameters. According to the traditionally change of the appearance of flexural hinge, the different parameters will be designed through to the differences of several combination. On the other hand, we use the Finite Element Method to analyze the kinematics behavior of different hinges. Finally, we come up with a series of complete data that provide designers a reference for designing.

Vibrissae (whiskers) are important components of the mammalian tactile sensory system, and primarily function as detectors of environmental vibrotactile cues. Pinnipeds possess the largest and most highly innervated vibrissae among mammals and their vibrissae demonstrate a diversity of shapes and likely mechanical properties. These two characteristics are important for vibrotactile sensory perception. Vibrissae of most phocid seals exhibit a beaded morphology with repeated sequences of crests and troughs along their length. I comparatively characterized differences in vibrissae morphologies among phocid species with a beaded profile, phocid species with a smooth profile, and otariids with a smooth profile using traditional and geometric morphometric methods to test the hypothesis that vibrissal morphologies are species-specific manipulations of a common pattern. The traditional and geometric morphometric datasets were subsequently combined by mathematically scaling each to true rank, followed by a single eigendecomposition. Quadratic discriminant function analysis demonstrated that 79.3, 97.8 and 100% of individuals could be correctly classified to taxon based on vibrissal shape variables in the traditional, geometric and combined morphometric analyses, respectively. At least three separate morphologies were identified since phocids with beaded vibrissae, phocids with smooth vibrissae, and otariids each occupied distinct morphospace in the geometric morphometric and combined data analyses. Another important characteristic that influences the transduction of vibrotactile information to the mechanoreceptors in the follicle-sinus complex is the materials properties of the vibrissae. Vibrissae were modeled as cantilever beams and flexural stiffness (EI) was measured to test the hypotheses that the shape of beaded vibrissae reduces flexural stiffness and that vibrissae are anisotropic (orientations differ in EI). Species were significantly different and smooth vibrissae were generally stiffer than beaded vibrissae. Beaded vibrissae decrease vibrations in flow, which, combined with lower flexural stiffness values, may enhance detection of small changes in flow from swimming prey. The anterior plane of the vibrissae is likely the most biologically significant in tracking hydrodynamic trails but had lower flexural stiffness values than the dorsoventral orientation. There is likely a complex interaction between shape and mechanical properties in pinniped vibrissae but the ecological and functional implications are currently unknown.

Made available in DSpace on 2014-06-11T19:28:55Z (GMT). No. of bitstreams: 0 Previous issue date: 2004-12-16Bitstream added on 2014-06-13T19:16:51Z : No. of bitstreams: 1 ribeiro_dg_me_arafo.pdf: 507473 bytes, checksum: 1c6ba03d7141c053da8a5a15fc65d0c1 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O uso do microondas tem sido indicado como um método efetivo na desinfecção de resinas acrílicas. Entretanto, há pouca informação sobre o efeito da irradiação do microondas nas propriedades mecânicas desses materiais. Considerando esses aspectos, o objetivo deste estudo foi avaliar o efeito da irradiação por microondas sobre as propriedades mecânicas de resistência à flexão e dureza de resinas acrílicas. Os corpos-de-prova para a realização dos testes mecânicos foram confeccionados com os seguintes materiais: Kooliner (K), Tokuso Rebase Fast (TR), Ufi Gel Hard C (UGH) e New Truliner (NT), todas resinas indicadas para reembasamento imediato, e Lucitone 550 (L), que é uma resina para base de prótese. Para cada material foram confeccionados 48 corpos-de-prova que foram divididos igualmente em seis grupos. As resinas autopolimerizáveis (K, TR, UGH e NT) foram submetidas à irradiação logo após a confecção, enquanto que os corpos-de-prova da resina termopolimerizável (L) permaneciam 50 l 2 horas em água a 37ºC l 1ºC antes da irradiação. Para o procedimento de irradiação, cada corpo-de-prova foi individualmente imerso em 200 mL de água destilada e submetido a dois ciclos de irradiação pelas microondas, para simular o envio da prótese ao laboratório e o retorno dela ao consultório odontológico. Cada corpo-de-prova foi irradiado a uma potência constante de 650 W, variando-se o tempo de exposição: 1 minuto (T1), 2 minutos (T2), 3 minutos (T3), 4 minutos (T4) ou 5 minutos (T5). O grupo controle (T0) foi submetido aos testes mecânicos sem ser irradiado pelas microondas. Os ensaios de resistência à flexão para todos os corpos-de-prova foram realizados em máquina MTS-810 Material Test System sob velocidade de 5 mm/minuto, utilizando o teste em três pontos a uma distância de 50 mm entre os apoios. Em seguida, um dos fragmentos do... / Microwave irradiation was previous suggested as an effective method for the disinfection of acrylic resins. However, little information is available concerning the effect of microwave irradiation on the mechanical properties of acrylic resins. The purpose of this study was to evaluate the effect of two cycles of a microwave disinfection procedure on the flexural strength and Vickers hardness of acrylic resins. Four autopolymerized resins (Kooliner- K, Tokuso Rebase Fast- TR, Ufi Gel Hard- UGH and New Truliner- NT) and one heat-cured resin (Lucitone 550- L) were used for preparing specimens. For each material, 48 specimens were made and equally divided into six groups. The relined specimens were submitted to disinfection procedures after polymerization and the denture base polymer specimens were stored in water for 50 l 2 hours at 37ºC l 1ºC prior to disinfection. The specimens were individually immersed in 200 mL of destilated water and microwaved twice, simulating when dentures come from the patient and before being returned to the patient. Each cycle of microwave disinfection was performed at 650 W for one of the following irradiation times: 1 minute (T1), 2 minutes (T2), 3 minutes (T3), 4 minutes (T4) or 5 minutes (T5). Control group (T0) specimens were subjected to mechanical tests without being disinfected. The flexural strength values of the materials were determined using a testing machine MTS-810 at a crosshead speed of 5 mm/minute using a three-point bending fixture with a span of 50 mm. Thereafter, one fragment of specimen was submitted to Vickers microhardness test. The values were determined by using a 25 gf load, after 30 seconds contact. Twelve hardness measurements were taken on each specimen and the average was then calculated. The flexural and hardness values were submitted to ANOVA and ...(Complete abstract, click electronic access below)

Indiana University-Purdue University Indianapolis (IUPUI) / Clinical evidence suggests that the use of liners in posterior composite restorations may increase the frequency of restoration fractures. Materials that have been used as liner materials for resin composite (RC) restoration include conventional glass ionomers, resin-modified glass ionomers (RMGI), and flowable composites. The aim of this study was to compare the flexural strength of a monolayer of resin composite with that of a bilayer of resin composite and liner. Four types of RC beams were tested: a monolayer control that is an un-lined RC (Tetric EvoCeram, Ivoclar Vivadent) and three “bilayer” specimens that consisted of this same RC lined with one of three liners. The three liners used included two RMGI cements (Vitrebond LC liner; 3M ESPE and, GC Fuji Lining LC; GC America) and a flowable resin composite (Tetric EvoFlow, Ivoclar Vivadent). Each group was tested after water storage for 24 h and 30 d. Altogether, eight, 12-specimen groups were fabricated and tested. Methods: A 25 x 2 x 2 mm mold was completely filled with the RC to form the control beams. To form the bilayer beams, this mold was filled with 0.5 mm of the liner and then with 1.5 mm of the RC. Specimens were stored in 37oC distilled for either 24 h or 30 d. Immediately prior to testing, the 30-day groups were also thermocycled 2500 times, between water baths at 7 oC and 48oC with a 30-s dwell time and a 10-s transit time. Flexural strength was determined using a three-point–bending device. A twoway analysis of variance (ANOVA) with interactions was used to investigate how liner group (or no liner) and storage time affected strength. Results: The interaction between liner type and storage time was significant (p = 0.0128). The un-lined RC (the monolayer beam) was significantly stronger after 24 h than after 30 d in water (p = 0.0098). Water storage between 24 h and 30 d did not change the flexural strength of any of the bilayer (lined) beams (p > 0.05). After storage for 24 h and also for storage for 30 d, both un-lined RC and RC lined with the flowable RC exhibited significantly higher flexural strength (p = 0.0001) than the bilayer beams lined with either RMGI liners.