SAGE Publications
0021-9983
1530-793X
Cơ quản chủ quản: SAGE Publications Ltd
Lĩnh vực:
Mechanics of MaterialsMaterials ChemistryMechanical EngineeringCeramics and Composites
Các bài báo tiêu biểu
Residual failure pressures and fatigue life of filament-wound composite pipes subjected to lateral impact This study presents the effect of impact energy on the static failure pressures, and fatigue life of composite pipes. The specimens manufactured have inner diameter 100 mm and length 400 mm. Impact tests were realized at three different energy levels 5.0, 7.5, and 10.0 J. Force–deflection curves were plotted. Impacted and non-impacted specimens were subjected to internal pressure statically and dynamically to obtain failure pressure and fatigue life of the composite pipe, respectively. Results indicate that leakage and eruption pressures for static test decrease and perspiration, leakage, and eruption cycles decrease by lateral impact.
Tập 46 Số 15 - Trang 1787-1794 - 2012
Fatigue failure analysis of surface-cracked (±45°)<sub>3</sub> filament-wound GRP pipes under internal pressure In this study, the fatigue behavior of (±45°)3 filament-wound composite pipes with a surface crack under alternating internal pressure was investigated. Glass-reinforced plastic (GRP) pipes were made of E-glass/epoxy and tested in the open-ended condition. The pipes had a surface crack with a notch–aspect ratio of a/c = 0.2 and notch-to-thickness ratios of a/t = 0.25, 0.38, or 0.50 in the axial direction. Tests were carried out in accordance with ASTM D2992. This standard offers 25 cycles/min and a load ratio of R = 0.05. Tests were performed at three different load levels: 50%, 40%, and 30% of ultimate hoop stress. Whitening, leakage, and final failure of GRP pipes were observed, and fatigue test results were presented by means of S–N curves.
Tập 46 Số 9 - Trang 1041-1050 - 2012
Scale and Size Effects on Dynamic Response and Damage of Glass/Epoxy Tubular Structures The impact behavior of composite materials has been extensively studied but interest has been centered on flat plates. For underwater applications, thick composite cylinders are employed and several questions must be addressed concerning the influence of accidental impact. The aim of this work is to study the dynamic response of tubular structures. Such structures find many applications but the damage upon impact is not taken into account during their dimensioning. However, at the time of their handling or in service the damage introduced by accidental impact can compromise their capacity to fulfill their function. The cylinders are thick and consist of epoxy matrix and glass fiber reinforcement. After having observed the nature of the damage related to the static and dynamic loading, the scale and size effects on dynamic response and damage are examined. The studies reveal that the dynamic responses show a satisfactory correlation with predictions based on rules of similitude.
Tập 41 Số 5 - Trang 547-558 - 2007
Mechanical behavior of GRP pressure pipes with addition of quartz sand filler In comparison with steel, concrete, and polymeric pipes, glass-reinforced plastic (GRP) pressure pipes use more expensive raw materials. Thus, despite of their attractive structural performance, mainly in terms of mechanical strength combined with low weight, the higher cost can be a limitation in many applications. In this scenario, an alternative to reduce the final price of GRP pipes is the addition of quartz sand filler. In this experimental and numerical study, filament-wound E-glass/polyester pipes with nominal inside diameter of 300 mm and wall thickness of 5.7 mm were produced with the incorporation of quartz sand as filler and tested to failure under internal pressure. The mechanical behavior of the composite pipes was evaluated experimentally, throughout short-time hydraulic failure pressure tests, as well as using finite element analysis (FEA). In the FEA simulations, the shell wall was modeled as an axisymmetric layered orthotropic material. A good agreement, varying from 96% to 98%, was obtained between the average hydraulic failure pressure measured and FEA predicted failure pressures, using Tsai—Hill and Hoffman failure criteria, respectively.
Tập 45 Số 6 - Trang 717-726 - 2011
Preparation of poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate)/silicon dioxide nanoparticles composite films with large thermoelectric power factor Herein, poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS)/silicon dioxide nanoparticles (SiO2 -NPs) composite films were prepared via a simple method by direct vacuum filtration technique. The effect of SiO2 -NPs contents on the thermoelectric performance of PEDOT:PSS was investigated systematically. PEDOT:PSS nanofilm without SiO2 -NPs exhibited a maximum electrical conductivity of 1487 S cm−1 and a Seebeck coefficient of 17.4 µV/K. When the SiO2 -NPs were introduced, the Seebeck coefficient of PEDOT:PSS/SiO2 -NPs nanocomposite films increased to a peak value of 24.2 µV/K at 20 wt% SiO2 -NPs, and the corresponding electrical conductivity was 1132 S/cm. Although a compromise in electrical conductivity, a large optimized power factor up to be 66.29 µW/m K2 was achieved due to the contribution of improved Seebeck coefficient. The presence of SiO2 -NPs in the composite films with small-size structure and abundant grain boundaries may cause the carrier scattering and filtering effect, which accounts for the enhanced Seebeck coefficient.
Tập 52 Số 5 - Trang 621-627 - 2018
Effect of Finite Width on Deflection and Energy Release Rate of an Orthotropic Double Cantilever Specimen The problem of an orthotropic cantilevered plate subjected to a uniformly distributed end load is solved by the Rayleigh-Ritz energy method. The result is applied to laminated composite, double cantilevered specimens to estimate the effect of crack tip constraint on the transverse curvature, deflection and energy release rate. The solution is also utilized to determine finite width correction factors for fracture energy characterization tests in which neither plane stress nor plane strain conditions apply.
Tập 22 Số 7 - Trang 640-656 - 1988
Thermoplastic variable stiffness composites with embedded, networked sensing, actuation, and control We present a composite material consisting of a thermoplastic base material and embedded, networked sensing, actuation, and control to vary its stiffness locally based on computational logic. A polycaprolactone grid provides stiffness at room temperature. Each polycaprolactone element within the grid is equipped with a dedicated heating element, thermistor, and networked microcontroller that can drive the element to a desired temperature/stiffness. We present experimental results using a 4 × 1 grid that can assume different global conformations under the influence of gravity by simply changing the local stiffness of individual parts. We describe the composite structure and its manufacturing, the principles behind variable stiffness control using Joule heating, local sliding mode control of each polycaprolactone bar’s temperature and function, and limitations of the embedded multi-hop communication system. The function of the local temperature controller is evaluated experimentally.
Tập 49 Số 15 - Trang 1799-1808 - 2015
Progressive Failure Behaviors of 2D Woven Composites This paper focuses on understanding the progressive failure behavior of woven composites. Five weaves, i.e. plain, 4-, 5-, 8-harness satin and twill, are considered. Rather than developing a new progressive failure analysis approach, the focus is placed on comparing the damage behaviors of the various weaves predicted by the selected failure criterion and property degradation model. The loading conditions include uniaxial tension and compression. The discussions focus on (1) the effect of the woven architecture on the predicted progressive failure behaviors (2) the similarities and difference in the damage initiation and evolution mechanisms between the plain and satin weaves and (3) the sensitivity of the predicted progressive failure behavior to assumptions about geometric nonlinearity and the property degradation model. The results have shown that the weave architecture (i.e. weave pattern) has significant effects on the predicted progressive failure behaviors even if the composites have the same overall fiber volume fraction, tow waviness and tow cross-section. Comparisons of the damage initiation and evolution mechanisms in the plain and 4-harness satin weaves indicate significant similarities in the damage behaviors in the comparable regions for the two weaves. The results also show that the predicted response of low waviness composite, which is more commonly seen in most structural applications, is quite insensitive to the assumed property degradation model. This imposes difficulties in validating a model by comparison with test results for low waviness composites.
Tập 37 Số 14 - Trang 1239-1259 - 2003
Stiffness and Expansion Estimates for Oriented Short Fiber Composites
Tập 3 Số 4 - Trang 732-734 - 1969
Effect of Environmental Exposure on the Mechanical and Bonding Properties of Hybrid FRP Reinforcing Bars for Concrete Structures Hybrid fiber-reinforced polymer (FRP) rebar has emerged as one of the most promising and affordable solutions to the brittle failure problems of ordinary FRP rebar in concrete structures. Hybrid FRP rebar stress-strain curves are linearly elastic, and contain a definite yield point followed by plastic deformation. In this study, the long-term durability performance of hybrid FRP rebar is evaluated. The mechanical properties and durability of one type of carbon FRP rebar, one type of glass FRP rebar, and two types of hybrid FRP rebars are investigated. The rebar specimens are exposed to twelve different environments, including an alkaline solution, an acid solution, a salt solution, deionized water, and repeated freezing and thawing. Short-beam, tensile, and bond tests are used to analyze the mechanical properties and durability of the rebar. The experimental results confirm the desirable resistance of hybrid FRP rebar to aggressive environments.
Tập 40 Số 12 - Trang 1063-1076 - 2006