Search

The limitations of oxide/oxide ceramic matrix composites lie in the need to improve their mechanical properties. It is challenging to reconcile the conflict between matrix densification at high temperature and the potential thermal damage to fibers. The concept of using element doping to control the sintering behavior of matrix was initially applied to prepare alumina-based ceramic matrix composites (CMCs). To lower the sintering temperature of the Al 2 O 3 matrix, MnO 2 dopant was used as a sintering aid. As a result, the thermal damage to alumina fibers was decreased, and the mechanical properties of the composite were significantly enhanced. The effect of MnO 2 content on the bending strength and micro-morphology of the composite was investigated. The composite exhibits optimal mechanical properties with a 0.01 wt% MnO 2 doping, and its bending strength is approximately 405 MPa. The investigation aimed to determine the mechanism by which the fluctuation in micro-mechanical properties of the composites with different MnO 2 contents. After the thermal aging at 1000℃ for 500 h, the bending strength of the N610/Al 2 O 3 -0.01 composite decreases to 297 MPa. The evolution and mechanism of thermal aging damage have been studied. [ABSTRACT FROM AUTHOR]

The α-mixture model, as a flexible family of distributions, is an effective tool for modeling heterogeneity inS population. This article investigates the hazard rate of α-mixture in terms of hazard rates of mixed baseline distributions. In particular, when the baseline hazard rate follows either additive or multiplicative models an inverse problem to obtain the baseline hazard is solved. We, also, study the α-mixture hazard rate ordering for the ordered mixing distributions in the sense of likelihood ratio order. Sufficient conditions to order two finite α-mixtures in the sense of dispersive ordering are provided. Finally, it is shown that the hazard rate of the finite α-mixture in the multiplicative model tends to the hazard rate of the strongest (weakest) population as α → + ∞ ( − ∞ ). Several examples are presented to illustrate theoretical findings. [ABSTRACT FROM AUTHOR]

In this paper, the fiber-reinforced foam sandwich composites were prepared by Vacuum-Assisted Resin Injection (VARI). Then the damp heat aging experiment was carried out on the specimens using a constant temperature and humidity test chamber and the bending property of the treated specimens was investigated using the universal testing machine. Finally, the microstructural analysis of scanning electron microscopy (SEM) technique was utilized for damage mechanism analysis. The results show that the mechanical properties of the specimens decrease after the damp heat aging, and the unidirectional laminated fibers have better resistance to the hot and humid environment than the orthogonal laminated fibers. The setting of drainage holes can increase the resistance of the specimens to the hot and humid environment, and the mixed fibers reduce the residual mechanical properties of the fiber-reinforced foam sandwich composites after the damp heat aging. These findings provide guiding insights for the future design and fabrication of more durable composite materials. Moreover, they are of significance to improve the material performance, extend its service life, and expand its range of applications. [ABSTRACT FROM AUTHOR]

In order to discuss the effect of different combing processing routes on polyester cotton blended fabric style, polyester and cotton were separately combed then blended to spin polyester cotton blended combed yarn according to blending ratio of 65/35. Additionally, polyester were carded, cotton were combed and blended to spin semi-combed polyester cotton blended yarn. Both the polyester cotton blended combed yarn and polyester cotton blended semi-combed yarn were processed into polyester cotton blended combed fabric and polyester cotton blended semi-combed fabric using the same weaving and dyeing processes. The two types of fabric were tested for various style parameters, including tensile, shear, bending, compression and surface characteristics using KES fabric style analyzer. The results showed that compared with polyester cotton blended semi-combed fabric, the polyester cotton combed blended fabric exhibited improvements in various style aspects. The bending rigidity was reduced 20%, bending hysteresis distance was reduced 17%, compression work ratio was reduced 22% and fluctuation of friction coefficient was reduced 18%. It is considered that the polyester cotton blended combed fabric has better qualities in terms of softness, smoothness and resilience compared to the polyester cotton blended semi-combed fabric. [ABSTRACT FROM AUTHOR]

Owing to their great potential to enhance the structural, mechanical, and electrical properties of materials, numerous researchers have dedicated their efforts to manufacturing multi-walled carbon nanotubes (MWCNTs)-reinforced composites via additive manufacturing (AM) to leverage AM's ability to fabricate intricate structural components. However, there is currently limited research on MWCNTs in photosensitive resin (PR) systems processed via a type of vat photopolymerization AM technique - digital light processing (DLP). Additionally, the distribution pattern of MWCNTs in PR systems is still unknown. To address these research gaps, this investigation focuses on fabricating MWCNTs-reinforced PR (MWCNTs-PR) via DLP and studying the effects of MWCNTs content on microstructure characterizations and mechanical properties of MWCNTs-PR. These results show that PR with 0.05 wt% MWCNTs addition exhibits a 25 % increase in elastic modulus and a 2 % increase in bending strength compared to pure PR. To achieve a more uniform distribution of MWCNTs in the PR, a combination of an ultrasonic bath and mechanical stirring was adopted. To further investigate the mechanism behind MWCNTs-enhanced bending resistance, a multi-material layered 3D printing structure was developed. The experimental findings reveal that the 10001 structure yields the highest bending modulus, surpassing the control group by 14.9 %. To validate the bending resistance mechanism attributed to MWCNTs-PR, finite element analysis was conducted.

In this study, 6061-T6 aluminum alloys were plated with electroless Ni–P with different phosphorus content and three-point bending and rotating bending fatigue tests. The effects of hydrogen due to plating on mechanical properties were investigated. It was shown that the ductility decreased immediately after low-phosphorus type and high-phosphorus type Ni–P plating by three-point bending test because a hydrogen was introduced into the alloys. The fatigue strength of the low-phosphorus type Ni–P plated specimen was higher than that of the un-treated specimen, while that of the high-phosphorus type plated specimen was much lower. It is clear that the fatigue strength differs greatly depending on the phosphorus content in the plating film. 6061-T6 aluminum alloy have been reported to exhibit no hydrogen embrittlement in low strain rate tensile tests under wet condition. However, it was found that hydrogen embrittlement occurred when 6061-T6 aluminum alloy was plated with the high-phosphorus type electroless Ni–P and fatigue-tested on rotating bending machine. [ABSTRACT FROM AUTHOR]

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Background The aim of this study was to evaluate the phase composition, phase transformation temperatures, bending property, and cyclic fatigue resistance of different heat-treated nickel-titanium (NiTi) rotary instruments with the same tip diameter and taper at room (RT; 25 ± 1 °C) and body (BT; 37 ± 1 °C) temperatures. Methods Five heat-treated NiTi rotary instruments, HyFlex EDM (EDM), HyFlex CM (CM), Vortex Blue (VB), RE file CT (RE) and JIZAI, and a non-heat-treated NiTi rotary instrument (Mtwo) with a size 40, 0.04 taper were investigated. Temperature-dependent phase transformation was examined with differential scanning calorimetry (DSC). The bending loads of the instruments at RT and BT were evaluated using a cantilever-bending test. Cyclic fatigue resistance at RT and BT was measured using a dynamic test, during which the instruments were rotated in combination with a 2-mm back-and-forth motion in an artificial curved canal, and the number of cycles to failure (NCF) was determined. The results were analyzed using two-way repeated measures analysis of variance, a simple main effect test, and the Bonferroni test (α = 0.05). Results DSC results indicated that EDM and Mtwo were primarily composed of martensite/R-phase and austenite, respectively, while the other heat-treated instruments were composed of a mix of martensite/R-phase and austenite at the tested temperatures. Regardless of the temperature setting, the bending loads of heat-treated instruments were significantly lower than those of Mtwo (p 0.05). Conclusions Heat-treated NiTi instruments exhibited lower bending loads and higher NCF values than Mtwo. However, this tendency was less pronounced at BT than at RT, especially in the NCF values of instruments with a mixture of martensite/R-phase and austenite phases at the tested temperatures.

The reversed hazard rate, defined as the ratio of the density to the distribution function, has recently drawn great interest in reliability and survival analysis due to its usefulness in the analysis of left-censored data. This paper develops the mixture model of discrete reversed hazard rates and studies its main properties. Similar to the continuous case, results of the bending property for the reversed hazard rate in discrete case are studied. In addition, mixtures of the mean inactivity time, which are closely related to the reversed hazard rate, are discussed and the corresponding results of its bending property are also investigated. Preservation of aging properties under both mixtures of reversed hazard rate and mean inactivity time is discussed as well. As a special case, the proportional discrete reversed hazard rate model is presented and the bending properties for this case are also discussed. Finally, stochastic comparisons of the mixture discrete reversed hazard rates of two mixed populations are addressed. [ABSTRACT FROM AUTHOR]

Background: The aim of this study was to evaluate the phase composition, phase transformation temperatures, bending property, and cyclic fatigue resistance of different heat-treated nickel-titanium (NiTi) rotary instruments with the same tip diameter and taper at room (RT; 25 ± 1 °C) and body (BT; 37 ± 1 °C) temperatures. Methods: Five heat-treated NiTi rotary instruments, HyFlex EDM (EDM), HyFlex CM (CM), Vortex Blue (VB), RE file CT (RE) and JIZAI, and a non-heat-treated NiTi rotary instrument (Mtwo) with a size 40, 0.04 taper were investigated. Temperature-dependent phase transformation was examined with differential scanning calorimetry (DSC). The bending loads of the instruments at RT and BT were evaluated using a cantilever-bending test. Cyclic fatigue resistance at RT and BT was measured using a dynamic test, during which the instruments were rotated in combination with a 2-mm back-and-forth motion in an artificial curved canal, and the number of cycles to failure (NCF) was determined. The results were analyzed using two-way repeated measures analysis of variance, a simple main effect test, and the Bonferroni test (α = 0.05). Results: DSC results indicated that EDM and Mtwo were primarily composed of martensite/R-phase and austenite, respectively, while the other heat-treated instruments were composed of a mix of martensite/R-phase and austenite at the tested temperatures. Regardless of the temperature setting, the bending loads of heat-treated instruments were significantly lower than those of Mtwo (p < 0.05). EDM showed the lowest bending loads and highest NCF at both temperatures (p < 0.05). CM, VB, and JIZAI showed significantly higher bending loads at BT than at RT (p < 0.05). The NCF of all the heat-treated instruments, except VB, was lower at BT than at RT (p < 0.05). At BT, the NCF of CM, VB, RE, and JIZAI were not significantly higher than that of Mtwo (p > 0.05). Conclusions: Heat-treated NiTi instruments exhibited lower bending loads and higher NCF values than Mtwo. However, this tendency was less pronounced at BT than at RT, especially in the NCF values of instruments with a mixture of martensite/R-phase and austenite phases at the tested temperatures. [ABSTRACT FROM AUTHOR]

With the development of smart and multi-functional textiles, conductive yarns are widely used in textiles. Conductive yarns can be incorporated into fabrics with traditional textile techniques, such as weaving, knitting and sewing. The electromechanical properties of conductive yarns are very different from conventional yarns, and they also affect the processability during end-product manufacturing processes. However, systematic evaluation of the electromechanical properties of commercial conductive yarns is still elusive. Different conductive materials and production methods for making conductive yarns lead to diverse electromechanical properties. In this work, three types of conductive yarn with different conductive materials and yarn structures were selected for electromechanical characterization. A total of 15 different yarns were analyzed. In addition, the change of resistance with strain was tested to simulate and predict the possible changes in electrical properties of the yarn during weaving, knitting, sewing and other end uses. It was found that Metal-based yarns have good electrical properties but poor mechanical properties. The mechanical properties of Metal-coated yarns are similar to conventional yarns, but their electrical properties are relatively poor. The data shown in this research is instructive for the subsequent processing (weaving, knitting, sewing, etc.) of yarns.

Five groups of three‐point bending tests of wood plastic composites (WPCs) at different temperatures were conducted. The test temperatures ranged from −40 to 40°C, and the temperature difference of each group was 20°C. The results show that the bending strength and elastic modulus of the specimens decrease continuously with increasing temperature. Twenty‐four‐hour bending creep tests of WPCs under a 50% stress level were completed at different temperatures. The Findley model predicted the short‐term creep of WPCs better. According to the results of the short‐term creep tests, the horizontal shift factor was introduced based on the Prony series model. Then, we proposed a formula for creep compliance over time at different temperatures to predict the long‐term creep performance of WPCs under a 50% stress level at different temperatures. The results indicate that when the test temperature is less than 0°C, WPCs can hold the load for 50 years without entering the tertiary creep stage; at 20°C, the WPC specimen will fail at 24 days, whereas at 40°C, the specimen can only last for 24 h and then enters the tertiary creep stage until fracture damage occurs. [ABSTRACT FROM AUTHOR]

In order to study the influence of the cavity inclination angle bending performance of pneumatic soft actuators, two kinds of soft actuators were designed, one with a five-degree-angle cavity structure, and the other with a hybrid variable-degree-angle cavity structure. The bending performance of zero-degree-angle, five-degree-angle, and hybrid variable-degree-angle soft actuators was investigated by experimental methods and the ABAQUS finite element simulation method. The results show that, under seven different pressure loads, the mean absolute error between the experimental results and the numerical simulation results for the zero-degree-angle soft actuator was 0.926, for the five-degree-angle soft actuator it was 1.472, and for the hybrid variable-degree-angle soft actuator it was 1.22. When the pressure load changed from 4 kPa to 16 kPa, the five-degree-angle soft actuator had the largest range-of-angle variation, with the bending angle increasing 193.31%, from 26.92 degrees to 78.97 degrees. In the same longitudinal displacement, the five-degree-angle soft actuator had the largest lateral displacement variation, and the bending effect was the best compared with the zero-degree-angle soft actuator and the hybrid variable-degree-angle soft actuator. According to the experimental and numerical simulation results, with the same structural parameter design, the cavity tilt angle increases, which can increase the bending angle variation range and improve the bending performance of soft actuators. [ABSTRACT FROM AUTHOR]

In response to the defects of easy delamination, poor impact resistance, and low toughness in laminates, intra-layer aramid/glass hybrid weft-knitted reinforced composites without lamination were designed and prepared. This paper investigated the tensile, bending, and impact response of aramid/glass hybrid weft-knitted reinforced composites. Homogeneous and hybrid composites with glass: aramid hybrid ratios of 1:1, 2:1, 3:1, and hybrid modes of transverse hybrid, oblique hybrid, and vertical interlocking hybrid were prepared by vacuum resin transfer molding (VARTM) technique. The tensile and bending properties were evaluated from stress, modulus, and strain/deflection, and a scanning electron microscope (SEM) was employed. The impact response was analyzed from peak force, maximum displacement, and energy absorption. The results confirm that interlacing brittle glass yarns with aramid yarns exhibits a positive hybrid effect. The ratios of 50%, 33%, and 25% aramid fiber in the transverse hybrid enhanced the longitudinal strength by 72.86%, 52.13%, and 22.01%. The mechanical properties of the oblique hybrid are similar in warp and weft direction; by contrast, the other two hybrid methods demonstrate mechanical anisotropy. This article implements the preparation and mechanical properties research of non-laminated hybrid composites based on weft-knitted structures, which broadens the design and selection of prefabricated components for hybrid composites. [ABSTRACT FROM AUTHOR]

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Solid wood bending component has good mechanical properties and unique artistic characteristics. To investigate bending properties of solid wood and its mechanism, this paper has conducted the studies of softening and bending teakwood which is chosen as raw material, vacuum impregnation was carried out with environmentally friendly triethanolamine (TEA), sodium chloride (NaCl) and sodium dodecyl benzene sulfonate (SDBS) as compound softening solution, and the wood was softened with superheated steam as the medium. The results show that the infiltration of softening solution can increase the content of O and N elements in the wood and form C-NH2 and C–N bonds with C element. When the concentration of softening solution is 15%(m/m), the wood presents the best bending property, and the bending coefficient can reach 1/9.24, which is 20.48% higher than that of the untreated wood, and the qualification rate of bending components is increased to 85%. After drying and shaping, compression strength parallel to grain and bending strength increased by 22.91% and 20.82%, as well the indentation modulus and hardness of the cell wall increased by 16.70% and 21.45%, respectively. Meanwhile, the wet swelling rate and chord length change rate decreased by 51.39% and 3.37%. [ABSTRACT FROM AUTHOR]

In this study, 6061--T6 aluminum alloys were plated with electroless Ni--P with different phosphorus content and three--point bending and rotary bending fatigue tests. The effects of hydrogen due to plating on mechanical properties were investigated. It was shown that the ductility decreased immediately after low--phosphorus type and high--phosphorus type Ni--P plating by three--point bending test because a hydrogen was introduced into the alloys. The fatigue strength of the low--phosphorus type Ni--P plated specimen was higher than that of the untreated specimen, while that of the high--phosphorus type plated specimen was much lower. It is clear that the fatigue strength differs greatly depending on the phosphorus content in the plating film. 6061--T6 aluminum alloy have been reported to exhibit no hydrogen embrittlement in low strain rate tensile tests under wet condition. However, it was found that hydrogen embrittlement occurred when 6061--T6 aluminum alloy was plated with the high--phosphorus type electroless Ni--P and fatigue--tested on rotary bending machine. [ABSTRACT FROM AUTHOR]

The widespread applications of W in the fusion reactor are limited by its low-temperature brittleness, recrystallization brittleness, and irradiation-induced brittleness. Many toughening methods were used to improve the brittleness of W, such as adding second-phase particles, adding W fibers, preparing laminated composite, and so on. Among these, preparing laminated W-based composites has been proven to effectively improve both the low-temperature and high-temperature toughness of W. In this study, W/M/TiN/Ta-laminated composites with transition metal layer (M) were synthesized through the spark plasma sintering (SPS) at three different temperatures. The effects of nano-scale (Ni, Ti, and Cr) and micron-scale (Ni, Ti, and V) transition layers on the bending and interfacial properties of the W/M/TiN/Ta composite were studied via an electron probe micro-analyzer (EPMA) and transmission electron microscope (TEM). Compared with W/TiN/Ta, the flexural strength and strain of W/Ninm/TiN/Ta were increased by 25.6% and 17.6%, respectively. Ni, Ti, and V micron transition layers can improve the combination of the W–TiN interface and decrease the joining temperature. The micron V layer has the best strengthening effect. The flexural strength of W/V/TiN/Ta reached 1294 MPa, much higher than W/Ta's 1041 MPa. [ABSTRACT FROM AUTHOR]

In response to the defects of easy delamination, poor impact resistance, and low toughness in laminates, intra-layer aramid/glass hybrid weft-knitted reinforced composites without lamination were designed and prepared. This paper investigated the tensile, bending, and impact response of aramid/glass hybrid weft-knitted reinforced composites. Homogeneous and hybrid composites with glass: aramid hybrid ratios of 1:1, 2:1, 3:1, and hybrid modes of transverse hybrid, oblique hybrid, and vertical interlocking hybrid were prepared by vacuum resin transfer molding (VARTM) technique. The tensile and bending properties were evaluated from stress, modulus, and strain/deflection, and a scanning electron microscope (SEM) was employed. The impact response was analyzed from peak force, maximum displacement, and energy absorption. The results confirm that interlacing brittle glass yarns with aramid yarns exhibits a positive hybrid effect. The ratios of 50%, 33%, and 25% aramid fiber in the transverse hybrid enhanced the longitudinal strength by 72.86%, 52.13%, and 22.01%. The mechanical properties of the oblique hybrid are similar in warp and weft direction; by contrast, the other two hybrid methods demonstrate mechanical anisotropy. This article implements the preparation and mechanical properties research of non-laminated hybrid composites based on weft-knitted structures, which broadens the design and selection of prefabricated components for hybrid composites. [ABSTRACT FROM AUTHOR]

Taking the three-directional orthogonal preform with different Z-direction fiber distance as the research object, the carbon/carbon (C/C) composites were prepared by the combination of chemical vapor infiltration and resin impregnation, and the effect of weaving parameters on the microstructure and bending performance of C/C composites were studied. The calculation model was established by taking the smallest repeated structure of three-directional orthogonal preform as a unit, and the relationship between fiber content and weaving parameters of three-directional preform was obtained and verified. The results show that the fiber content of preform is increased with the decrease of Z-direction fiber distance and X, Y-direction fiber layer distance; when the Z-direction fiber distance is increased, the twist deformation of the fiber interweave becomes larger, resulting in the change of the pore structure of the preform; under the same densification process, the change of pore structure affects the composition and distribution of carbon matrix in C/C composites, but has no effect on the morphology of carbon matrix; when the fiber content in X, Y-direction is increased and the distance between fibers in Z-direction is decreased, the flexural strength of the C/C composites is higher.

In order to study the influence of the cavity inclination angle bending performance of pneumatic soft actuators, two kinds of soft actuators were designed, one with a five-degree-angle cavity structure, and the other with a hybrid variable-degree-angle cavity structure. The bending performance of zero-degree-angle, five-degree-angle, and hybrid variable-degree-angle soft actuators was investigated by experimental methods and the ABAQUS finite element simulation method. The results show that, under seven different pressure loads, the mean absolute error between the experimental results and the numerical simulation results for the zero-degree-angle soft actuator was 0.926, for the five-degree-angle soft actuator it was 1.472, and for the hybrid variable-degree-angle soft actuator it was 1.22. When the pressure load changed from 4 kPa to 16 kPa, the five-degree-angle soft actuator had the largest range-of-angle variation, with the bending angle increasing 193.31%, from 26.92 degrees to 78.97 degrees. In the same longitudinal displacement, the five-degree-angle soft actuator had the largest lateral displacement variation, and the bending effect was the best compared with the zero-degree-angle soft actuator and the hybrid variable-degree-angle soft actuator. According to the experimental and numerical simulation results, with the same structural parameter design, the cavity tilt angle increases, which can increase the bending angle variation range and improve the bending performance of soft actuators.

In this paper we study the aging characteristics in mixtures of distributions, providing characterizations for their derivatives that explain the smooth behavior of the mixture. The classical preservation results for the reversed hazard rate, mean residual life and mean inactivity time are derived under a different approach than in previous studies. We focus on the variance of both the residual life and inactivity time in mixtures, obtaining some preservation properties. We also state conditions for weak and strong bending properties for the variance of the residual life and the inactivity time in mixtures. [ABSTRACT FROM AUTHOR]

Copyright of Cotton Textile Technology is the property of Cotton Textile Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Cotton Textile Technology is the property of Cotton Textile Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Cotton Textile Technology is the property of Cotton Textile Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Bulletin of the Chinese Ceramic Society is the property of Bulletin of the Chinese Ceramic Society Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The three-dimensional carbon fiber fabric was densified by chemical vapor infiltration and precursor impregnation cracking composite process, and the high thermal conductivity 3D C/C composite material with density of 1.95 g/cm3 was obtained. Using SEM, XRD, thermal conductivity test, linear expansion coefficient test and three-point bending experiment to study the effect of different heat treatment temperatures of 2350,2550,2850℃ on the microscopic morphology,structure, thermal conductivity, linear expansion coefficient and bending performance of 3D C/C composites. The results show that with the increase of the heat treatment temperature, the mesophase pitch-based carbon fiber graphite sheet structure becomes more obvious, the order of the pyrolytic carbon sheets evenly wrapped around the carbon fiber increases, and the arrangement between the sheets becomes more dense; the graphitization and thermal conductivity of 3D C/C composite materials improve; in the test temperature range of 250-1400℃, the linear expansion coefficient increases slightly with the increase of the test temperature, and the 3D C/C composite after different heat treatment temperatures. The linear expansion coefficient of the materials is -1×10-6-2×10-6℃-1, showing good "zero expansion". In addition, when the heat treatment temperature increases, the bonding of the carbon fiber and the matrix of the 3D C/C composite materials are weakened, resulting in the decrease in the bending strength and flexural modulus of the materials. A large number of long fibers are pulled out on the bending fracture surface of the materials after the high temperature heat treatment at 2850℃. In general, the fracture after three different heat treatment temperatures shows "pseudoplastic" fracture characteristics.

Copyright of Journal of Materials Engineering / Cailiao Gongcheng is the property of Journal of Materials Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The widespread applications of W in the fusion reactor are limited by its low-temperature brittleness, recrystallization brittleness, and irradiation-induced brittleness. Many toughening methods were used to improve the brittleness of W, such as adding second-phase particles, adding W fibers, preparing laminated composite, and so on. Among these, preparing laminated W-based composites has been proven to effectively improve both the low-temperature and high-temperature toughness of W. In this study, W/M/TiN/Ta-laminated composites with transition metal layer (M) were synthesized through the spark plasma sintering (SPS) at three different temperatures. The effects of nano-scale (Ni, Ti, and Cr) and micron-scale (Ni, Ti, and V) transition layers on the bending and interfacial properties of the W/M/TiN/Ta composite were studied via an electron probe micro-analyzer (EPMA) and transmission electron microscope (TEM). Compared with W/TiN/Ta, the flexural strength and strain of W/Ninm/TiN/Ta were increased by 25.6% and 17.6%, respectively. Ni, Ti, and V micron transition layers can improve the combination of the W–TiN interface and decrease the joining temperature. The micron V layer has the best strengthening effect. The flexural strength of W/V/TiN/Ta reached 1294 MPa, much higher than W/Ta’s 1041 MPa.

We investigated the relationship between the material properties and axial collapse behavior of hat-section hollow columns made of highstrength steels. Dynamic collapse tests of the columns and FEM simulations were conducted using high-strength steels with various tensile strengths and n-values. Materials that exhibited yield point elongation (YPEl) underwent enhanced accordion-type deformation in axial collapse owing to the occurrence of long wave buckling on the hat walls in the early stage of collapse. In addition, it was important to avoid fracture in the initial buckling region to induce progressive crumpling behavior. A high n-value of the material was favorable for avoiding fracture by increasing the bend radii and decreasing the strain concentration at the buckling regions on the hat walls, thereby resulting in stable progression of accordion-type folds. In conclusion, steels exhibiting YPEl and high n-values are favorable for inducing stable accordion-type deformation during axial collapse. [ABSTRACT FROM AUTHOR]

Ultrasonic seaming has become an important issue in recent years due to its various features. In this study, waterproof polyester knitted fabrics with polyurethane coating were used and the bursting strength, bending property and water permeability property of ultrasonic seaming were examined by changing various parameters. Besides, the ultrasonic seaming method was compared to conventional seaming and adhesive tape application. It is observed that there were high water permeability values generally in ultrasonic seaming and also fabrics with no water penetration were seen in this method, although, in some ultrasonic seaming parameters, values are lower than adhesive tape sealed ones. On the other hand, the bursting strength values of the ultrasonically sewn fabrics are found to be comparable to conventional seam and sealing adhesive tape when the optimum seaming parameters are determined. Also, it can be said that for the bending property according to increasing bending length values in this method compared with the others, ultrasonic seaming may find more usage areas where fabric stiffness is more advantageous. It has been observed that it is important to determine the fabric and ultrasonic sewing parameters according to the required performance property. [ABSTRACT FROM AUTHOR]

Bending resistance is regarded as a significant factor in achieving the widespread application of copper foils. This paper proposed a novel double-cross rolling process, which improved the bending fatigue life of copper foils by as much as 101% in comparation with conventional rolling. In this study, an investigation was conducted into the effects of double-cross rolling on the microstructure and texture of copper foils and the strengthening mechanism during the bending test was discussed. Results show that double-cross rolling could change the deformation behavior on bright and matt surfaces, resulting in equiaxed grains on both surfaces and some fine grains. Both surfaces were dominated by Brass and S textures, which can be attributable to from non-uniform and shear deformation respectively. Weak Goss and Cube textures resulted from the fine grains remaining after heat treatment. After double-cross rolling, the strain induced subgrains of copper foils facilitated the migration of grain boundary and grain rotation, thus improving bending property.

Copyright of Cotton Textile Technology is the property of Cotton Textile Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A novel Fe-17Mn-5Cr-1.5Al/Polyurethane(PU) high damping composite is successfully prepared via the adhesive welding method, which realizes a uniform controlled distribution of PU layers and their tight combinations with Fe-17Mn-5Cr-1.5Al layers. IF equipment is employed to measure the damping capacity of Fe-17Mn-5Cr-1.5Al/PU composites, and the results indicate the peak position of Fe-17Mn-5Cr-1.5Al/PU composite all shifts obviously toward higher temperature with the increasing measurement frequency, which indicates its typical relaxation features. The relationships among the IF peak height with the PU thickness or layer numbers have been studied, and the results indicate the relaxation strength of the IF peak reaches a maximum value when the PU thickness is 2. 0 mm or the PU layers number is 2. The high damping of Fe-17Mn-5Cr-1.5Al/PU composite is ascribed to the high damping of PU. In addition, the bending strength of Fe-17Mn-5Cr-1.5Al/PU composite increases with the increasing of PU thickness and layer numbers, and its good bending strength is ascribed to perfect mechanical property of Fe-17Mn-5Cr-1.5Al alloy. [ABSTRACT FROM AUTHOR]

2.5D shallow cross-linked Cf/Al composites with volume fraction of 50% were fabricated by vacuum pressure infiltration. The microstructure, bending and shear properties at room and high temperature were studied. The failure mechanism of bending and shear properties of the composites were analyzed. The results indicate that the warp and weft microstructures of 2.5D shallow cross-linked Cf/Al composites have some defects such as microvoid and fiber aggregation. The bending strength, bending modulus and shear strength of the composites at room temperature are 268.4 MPa,75.2 GPa and 41.0 MPa,respectively. The bending strength, bending modulus and shear strength of the composites at 350 ℃ are 139 MPa,70.9 GPa and 39.2 MPa,respectively. The bending strength,bending modulus and shear strength of the composites at 400 ℃ are 97.6 MPa,68.5 GPa and 29.9 MPa,respectively.The bending failure is mainly caused by the compressive stress on the inner surface, which leads to press fracture of the warp fiber bundle and the extrusion deformation of the weft fiber bundle. Tensile failure of composites is not obvious with the increase of testing temperature at the outer side tension. Shear failure occurs first in the damage interface of the matrix and fiber bundle, the fiber bundle is pulled out and the fracture surface is not at the same level at room temperature, the fracture of the fiber bundle shows 45° failure at 350,400 ℃.The buckling of the warp fiber bundle and the extrusion deformation degree of the weft fiber bundle become more and more serious with the increase of the test temperature.

Copper foils with excellent bending property were fabricated by double-rolling followed by cross rolling. The deformation characteristics of the two advanced rolling processes introduce high density of grain boundaries and dislocations in copper foils. Due to high densities of grain boundaries, dislocations and strong single texture, bending cracks are fine and dispersive, a 101.0% improvement of the bending fatigue life compared to copper foils fabricated by conventional rolling process. After bending fracture, concentrated dislocation and fine dispersive cracks can be observed.

Carbon/aramid fiber hybrid multi-layered biaxial weft knitted fabric was prepared in term of intraply hybridization. The mechanical properties and effect of hybrid ratio on mechanical properties were studied. Through uniaxial tension and three-point bending experiments, the tensile and bending properties and effect of hybrid ratio on mechanical properties were obtained. The results show that the tensile properties of composites are improved by adding aramid fibers according to a certain hybrid ratio, which shows a positive hybrid effect. Due to the addition of aramid fibers with good elongation, the tensile fracture elongation of the composites obviously increases, and the failure modes of the composites appear complete brittle fracture mode (C12 material failure mode) and "broom" fiber fracture mode (C8A4, C6A6 material failure mode). Besides, the fracture toughness of carbon fiber reinforced composites is effectively improved by adding aramid fibers at a certain hybrid ratio. The flexural strength and modulus of carbon/aramid hybrid MBWK fabric reinforced composites decrease with the increasing of hybrid ratio. With aramid content changing from 42% (volume fraction, the same below)(C6A6) to 59.2% (C4A8), the decreasing ratio of the bending strength and bending modulus are high. The bending deflection of 0° samples with a hybrid ratio of 59.2% (C4A8) is the highest, the value is 7.49 mm, which is much higher than that of pure aramid fiber or carbon fiber reinforced composites. The bending deflection of all 90° samples is higher than that of pure aramid fiber or pure carbon fiber reinforced composites, which shows the positive hybrid effects.

Copyright of Journal of Materials Engineering / Cailiao Gongcheng is the property of Journal of Materials Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this paper we study the aging characteristics in mixtures of distributions, providing characterizations for their derivatives that explain the smooth behavior of the mixture. The classical preservation results for the reversed hazard rate, mean residual life and mean inactivity time are derived under a different approach than in previous studies. We focus on the variance of both the residual life and inactivity time in mixtures, obtaining some preservation properties. We also state conditions for weak and strong bending properties for the variance of the residual life and the inactivity time in mixtures.

This paper investigates the burnishing characteristics of a developed sliding burnishing method with active rotary tool targeting a martensitic stainless steel. Two types of martensitic stainless steel, annealing (AN) stainless steel and quenching and tempering (QT) stainless steel, were targeted. The burnishing characteristics evaluated included surface roughness, profile, microstructure, subsurface hardness, bending property, and corrosion resistance. A sufficiently smooth surface, approximately Ra = 0.1 μm and Ra = 0.016 μm in both materials, respectively, was obtained using the developed burnishing method; irregular profile smoothing occurred due to the material flow of the subsurface. The subsurface hardness increased at a depth of 40 μm or more when using the developed burnishing method on the AN material, but no effect was observed for the QT material. Moreover, the bending yield point and strength of the sheet shape workpiece increased by applying the burnishing process to the AN material. The influence of the burnishing process on the bending properties was also observed for the QT material. Corrosion resistance, which evaluated by the salt-spray test, can be improved through the burnishing process in AN material.

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

[Display omitted] As a multifunctional material, wood is widely used in interior decoration and construction engineering. The full-cell process of impregnating monomers into wood pores cavity in situ is one of the most common wood modification methods. However, this approach is time-consuming, material-wasting, and not environmentally friendly. In this study, we proposed a simple strategy to directly convert wood into high-performance composites by controlling wood surface penetration through resin pre-curing. A slight amount of resin used was sufficient to penetrate the wood surfaces, and the weight percent gain (WPG) of 11.45 %. High energy efficiency was achieved by simple temperature control (60 °C/120 °C). In addition, this method can rapidly produce wood composites with ultra-low density (0.51 g/cm3) and ultra-high specific bending strength (284 MPa·cm3g−1) in a very short time (4 h and 30 min). The results showed that the problem of excessive resin penetration was effectively solved by the pre-curing process, which enriched the gradient distribution of resin from the surface to the bottom of the wood and significantly improved the material properties. This efficient and environmentally friendly preparation strategy makes natural wood a low-cost, low-density, high-strength engineering material, which broadens the application of wood composites in construction engineering and interior decoration. [ABSTRACT FROM AUTHOR]

• The coatings are fabricated with TiC and Ni60 mixture powders as raw materials by laser cladding. • The effect of TiC content on microstructure and properties of TiC/Ni60 coatings is revealed. In this study, the composite coatings on Ti6Al4V alloy are fabricated with TiC and Ni60 mixture powders by laser cladding. The effect of TiC content on microstructure and properties of the coatings is investigated. Many TiC particles in large size are randomly distributed in the coatings. The coatings mainly contain TiC. TiC, TiC x , Ti 2 Ni, TiNi, TiB, Cr x B and Ti phase identified by XRD. The feature of the precipitates in the coatings is various due to different TiC. The forms of the precipitates are changed in the coatings with increasing the TiC content. The wear resistance of the coatings decreases with increasing the TiC content. Numerous plowing grooves with the debris particles and white scaly patterns are found in the sliding direction. With increasing the TiC content, the bending strength of the samples decreases. The brittle fracture feature are shown on the fracture surface of the coatings. [ABSTRACT FROM AUTHOR]

Copyright of Cotton Textile Technology is the property of Cotton Textile Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Carbon/aramid fiber hybrid multi-layered biaxial weft knitted fabric was prepared in term of intraply hybridization. The mechanical properties and effect of hybrid ratio on mechanical properties were studied. Through uniaxial tension and three-point bending experiments, the tensile and bending properties and effect of hybrid ratio on mechanical properties were obtained. The results show that the tensile properties of composites are improved by adding aramid fibers according to a certain hybrid ratio, which shows a positive hybrid effect. Due to the addition of aramid fibers with good elongation, the tensile fracture elongation of the composites obviously increases, and the failure modes of the composites appear complete brittle fracture mode (C12 material failure mode) and "broom" fiber fracture mode (C8A4, C6A6 material failure mode). Besides, the fracture toughness of carbon fiber reinforced composites is effectively improved by adding aramid fibers at a certain hybrid ratio. The flexural strength and modulus of carbon/aramid hybrid MBWK fabric reinforced composites decrease with the increasing of hybrid ratio. With aramid content changing from 42% (volume fraction, the same below)(C6A6) to 59.2% (C4A8), the decreasing ratio of the bending strength and bending modulus are high. The bending deflection of 0° samples with a hybrid ratio of 59.2% (C4A8) is the highest, the value is 7.49 mm, which is much higher than that of pure aramid fiber or carbon fiber reinforced composites. The bending deflection of all 90° samples is higher than that of pure aramid fiber or pure carbon fiber reinforced composites, which shows the positive hybrid effects.

To clarify inheritance of static bending properties in relation to elastic and plastic regions, air-dry density, microfibril angle of the S2 layer in latewood tracheid (MFA), and static bending properties (modulus of elasticity [MOE], modulus of rupture [MOR] and bending work) were examined for juvenile wood of 18 full-sib families in 20-year-old Cryptomeria japonica. Heritability of all traits ranged from 0.12 (bending work) to 0.51 (air-dry density). Based on the results from principal component analysis (PCA) and cluster analysis, the families were classified into four groups with different types of load-deflection curves, suggesting that both elastic properties and deflection in plastic region differed among families. Furthermore, families included in a group were produced from specific parents, suggesting that deflection in plastic region as well as elastic property is inheritable. It can be concluded that mating parents may affect elasticity and plasticity of offspring. [ABSTRACT FROM AUTHOR]

Copyright of Cotton Textile Technology is the property of Cotton Textile Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In Japan, where a safe and secure society has been established, stab proof clothing that are suitable for police and security officers supporting are required. So far, most of the stab-proof clothing is made of the metal plate or thick multi-layered fabric with high-strength fibers. It is commonly used as a stab-proof vest because it cannot cope with the large deformations, which caused by the joints such as arms or neck. This research aims to develop high flexible stab-proof clothing that can be applied in large-deformation part such as joints with high stab-proof performance. We developed a testing device that can measure bending characteristics under the same conditions as when the stab proof clothing is actually worn on the human body. The usefulness of the evaluation method was confirmed. And the factors that affect the bendability of the elbow joint were also be studied. The mechanical properties of the material and the gap between the arm and the cylindrical structure are greatly affected, and the effect of each bending angle on the bending moment is different. We considered the deformation of the material when it bending and then proposed a new stab-resistant material structure and trial production. The cylindrical bending test shows that the flexibility of the new structure is greatly improved. [ABSTRACT FROM AUTHOR]