Failure behavior and mechanical properties of unidirectional (UD) carbon fiber reinforced polyamide 6 (CF/PA6) and epoxy resin (CF/Epoxy) laminates were investigated through tensile tests in this ...study. The fracture modes of both CF/PA6 and CF/Epoxy were discussed based on the fiber orientation, interfacial properties, Mode II interlaminar fracture toughness and the brush width. Meanwhile, Global load sharing (GLS) model was employed to compare with the experimental mechanical properties and corresponding fracture mechanics model was employed to analyze the fracture behavior. The results showed that UD CF/PA6 laminates with weak interface but high Mode II interlaminalr fracture toughness mainly exhibited step-like fracture modes (77%) in interfacial fracture mode (Adhesive failure), while CF/Epoxy laminates with stronger interface but lower Mode II interlaminalr fracture toughness mostly showed splitting fracture mode (69%) in matrix fracture mode (Cohesive failure).
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Fiber reinforced composites (FRPs) with light weight did not exhibit the ductile failure mechanism which was related to metals. FRPs absorb lots of energy through progressive crushing modes by a ...combination of multi micro-crack, bending, delamination and friction. FRPs with half weight of traditional metals while absorb more than doubled energy. But FRPs were not used as energy absorption components in wide range; one of the most important reasons is their high manufacturing cost.
In this study, carbon fiber and aramid fiber were chosen as reinforcements and common epoxy resin was chosen as matrix to manufacture five types of different structures and raw materials of carbon/aramid and carbon/carbon fiber reinforced composite tubes through high productive and low cost winding method. Then specimens were dealt under 100°C condition for 100h, 200h and 400h treatment respectively. After that, energy absorption ability was tested by quasi static compression tests and microscope observation of cross section was taken to analyze the mechanism of failure. By optimizing different hybrid method, ratio and reasonable geometry shape of composites, low cost and high energy absorption components whose specific energy absorption (Es) were near 100kJ/kg could be manufactured to put to use on vehicles.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Recently, many analysis tools have been devised to offer insights into data generated via cytometry by time-of-flight (CyTOF). However, objective evaluations of these methods remain absent as most ...evaluations are conducted against real data where the ground truth is generally unknown. In this paper, we develop Cytomulate, a reproducible and accurate simulation algorithm of CyTOF data, which could serve as a foundation for future method development and evaluation. We demonstrate that Cytomulate can capture various characteristics of CyTOF data and is superior in learning overall data distributions than single-cell RNA-seq-oriented methods such as scDesign2, Splatter, and generative models like LAMBDA.
Two types of unidirectional carbon fiber reinforced plastic were fabricated using identical carbon fibers but different matrix systems. Thermoplastic polyamide 6 and thermosetting epoxy were used as ...matrices. A large number of on-axis tensile tests of unidirectional carbon fiber reinforced polyamide 6 (CF/PA6) and the unidirectional carbon fiber reinforced epoxy (CF/Epoxy) laminates were performed. Mechanical properties and failure behaviors are discussed based on fiber distribution, impregnation conditions and interfacial shear strength. Tensile strengths were predicted by means of a modified global load sharing model and compared with experimental results. Step-by-step tensile tests revealed the fracture process of 0-degree unidirectional CF/PA6 laminates.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
While experimental and informatic techniques around single cell sequencing (scRNA-seq) are advanced, research around mass cytometry (CyTOF) data analysis has severely lagged behind. CyTOF data are ...notably different from scRNA-seq data in many aspects. This calls for the evaluation and development of computational methods specific for CyTOF data. Dimension reduction (DR) is one of the critical steps of single cell data analysis. Here, we benchmark the performances of 21 DR methods on 110 real and 425 synthetic CyTOF samples. We find that less well-known methods like SAUCIE, SQuaD-MDS, and scvis are the overall best performers. In particular, SAUCIE and scvis are well balanced, SQuaD-MDS excels at structure preservation, whereas UMAP has great downstream analysis performance. We also find that t-SNE (along with SQuad-MDS/t-SNE Hybrid) possesses the best local structure preservation. Nevertheless, there is a high level of complementarity between these tools, so the choice of method should depend on the underlying data structure and the analytical needs.
One of the major concerns of carbon fiber-reinforced nylon 6 composites (CF/Nylon 6) is its sensitivity to environmental degradation, especially hygrothermal aging. In this study, neat nylon 6 plates ...and unidirectional CF/Nylon 6 laminates with different fiber orientations manufactured by hot compression method were subjected to water absorption tests by immersing them in 80 °C and 98 °C hot water for various time durations. The corresponding flexural mechanical properties, including the flexural modulus and flexural strength, of the as-prepared samples before and after water absorption were evaluated by using three-point bending tests. The effects of immersion time, fiber orientation, and water temperature on the flexural properties are discussed. Flexural cyclic tests were conducted to evaluate the stiffness degradation of neat nylon 6 and unidirectional CF/Nylon 6 laminates. Optical observation and scanning electron microscopy were used to observe the fracture behavior of unidirectional CF/Nylon 6 laminates before and after water absorption. Results indicated that the flexural modulus and strength of unidirectional CF/Nylon 6 laminates in different fiber orientations decreased by ≈ 8%–60% and ≈40%–60% after hot water immersion, which was mainly caused by the weakened matrix (the cleavage reaction of the main chain and plasticization of the matrix) and weakened interfacial properties (attack on the interface by hot water). The fracture behavior of 0° CF/Nylon 6 laminates after water immersion tended to be more ductile than those without hot water immersion.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In this paper, the aging resistance of glass fiber-reinforced thermoplastic composites was discussed and analyzed in terms of the effects of hygrothermal aging and the time-temperature dependence. ...Accelerated hygrothermal aging tests, static flexural tests at different temperatures and speeds, and dynamic mechanical analysis tests at multiple temperatures and frequencies were carried out. Hygrothermal aging reduces the tensile properties and heat resistance of GF/PA and GF/PET, although the influence on GF/PA was greater than that on GF/PET. However, hygrothermal aging does not affect the thermal decomposition temperature. For the GF/PET composites, both the static flexural and dynamic mechanical properties were time and temperature dependent. It was found that increasing the temperature and decreasing the loading rate had equivalent effects on reducing the flexural strength and modulus. The time-temperature superposition principle was applied to the static flexural modulus of GF/PET. According to the master curve obtained by the time-temperature superposition principle, it was predicted that the static flexural modulus of GF/PET composites will decrease by 69.4% over 10 years at the reference temperature of 30 °C.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Carbon Fiber Reinforced Composites (CFRPs) with light weights absorbed a large quantity of energy through the progressive crushing modes by a combination of multi micro-crack including fiber fracture ...and matrix fracture, bending, delamination, splitting, friction and so on. High manufacturing cost of CFRPs was one of the most important reasons for not being used as energy absorption components in wide range. In this study, five types of tubes were manufactured by filament winding method and crashworthiness performance was investigated experimentally. The effects of crushing speed, temperature treatment, raw material and structure including hybrid ratio, fiber orientation and thickness of tube wall on energy absorption capabilities were investigated through quasi-static and dynamic compression tests. Optical microscope observation of cross sections was taken to analyze the mechanism of failure. A hybrid carbon/aramid FRP tube after temperature treatment exhibited the highest Es in quasi-static test (98kJ/kg in average) and dynamic tests (82kJ/kg in average), which have excellent energy absorption management.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
A detailed investigation on the effects of hydrothermal aging on the mechanical and thermal performance of woven carbon-fiber-reinforced polyamide 6 (CF/PA6) laminates processed using hot compression ...molding is presented. A surface treatment with a polyurethane dispersion (PUD) agent is applied on CFs to enhance the interfacial bonding capability between the CF and PA6 matrix. The moisture uptake results indicate that untreated CF/PA6 laminates exhibit higher equilibrium moisture absorption (
M
∞
), corrected diffusion coefficient (
D
C
), and rate of diffusion (
k
) than treated CF/PA6 laminates, implying that the interface damage of untreated CF/PA6 laminates is more pronounced than that of treated CF/PA6 laminates. The mechanical performance of the CF/PA6 laminates reduces significantly after water absorption and hydrothermal aging. Nevertheless, PUD-treated composites exhibit higher remaining flexural property than the virgin composites, due to the improved durability of CF/PA6 interface, as verified by the scanning electron microscopy results. Dynamic mechanical properties (i.e.,
T
g
, storage modulus, and tan δ) of the treated CF/PA6 laminates degrade more slowly than those of the untreated CF/PA6 laminates. Finally, the relationships between flexural property retention and moisture absorption ratio (i.e.,
M
t
/
M
∞
), and between flexural property retention and tan δ for both types of CF/PA6 laminates are established.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
