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The development of vertical cracks in loess slopes often affects slope stability. Compared with the plane strain mechanism, the slope stability analysis under the three-dimensional (3D) failure mechanism is closer to the actual slope instability. Based on the upper bound method of plastic limit analysis, different failure mechanisms (face failure, toe failure and base failure) of 3D loess slope with pre-existing cracks are considered, the energy balance equation and its dimensionless critical height expression γH/c are established, and the upper bound solution of critical height is obtained by random search method. The effects of constraint width, slope angle, internal friction angle and crack depth on the critical height of 3D vertical cracked loess slopes are analyzed. The results indicate that for the toe failure mechanism, the critical height decreases with the increase of crack depth, and the increase in crack depth no longer affects the critical height after reducing to the critical crack depth (δ /H)min. The critical crack depth increases with the increase of slope angle β and decreases with the increase of internal friction angle φ. When the constraint width B/H

In this work, silicone polymer (PSOL)/glass fiber (GF)/epoxy (EP) composites were prepared by employing PSOL as interfacial modifier into GF/EP composites. The mechanical and dynamic mechanical properties of the composites were investigated to determine the optimal PSOL content. The effect of PSOL on the wettability of EP on GF was investigated. The micromorphology of the GF/EP composites was also examined by scanning electron microscope. The results demonstrate that the interfacial bonding between GF and epoxy resin was improved significantly by the addition of PSOL. Specifically, the interlaminar shear strength, tensile strength, elongation at break, and blending strength of the PSOL/GF/EP composites increased by 9.28%, 13.61%, 12.66%, and 19.22%, respectively. Moreover, the original thermal stability of the composites was improved by the incorporation of PSOL. This study highlights the effectiveness of PSOL as an interfacial modifier, enhancing the overall performance of GF/EP composites while improving their thermal stability. Highlights: Silicone polymer (PSOL)/glass fiber (GF)/epoxy (EP) composite material is made of glass fiber and epoxy resin by hand paste molding.Silicon polymers as interface modifiers can improve the interface between glass fiber and epoxy resin.PSOL/GF/EP composites have good mechanical properties.The glass transition temperature of GF/EP composites was increased by silicon polymer. [ABSTRACT FROM AUTHOR]

In this work, carbon nitride (C3N4) powder was oxidized by the Hummers oxidation method, and oxidized carbon nitride (O‐C3N4) was obtained. Epoxy (EP) was modified with O‐C3N4, and then carbon fiber fabric/epoxy (CF/EP) composites were prepared by hand‐pasting molding. The O‐C3N4 greatly improves the wettability of EP resin, enhances the interface properties of CF/EP composites, and makes the composites have better mechanical properties. The interlaminar shear strength (ILSS) is increased from 51.75 to 59.68 MPa, the tensile strength is increased from 564.54 to 635.39 MPa, the bending strength is increased from 809.64 to 938.81 MPa, and the impact strength is increased from 73.48 to 84.84 kJ/m2. Meanwhile, the dynamic mechanical properties of composites are also significantly improved. The energy storage modulus is increased from 14.9 to 21.4 GPa, with an increase of 43.6%. Highlights: Developing carbon fiber composites is conducive to industrial applications.O‐C3N4 effectively improves the mechanical properties of the composite.O‐C3N4 has the advantages of simple synthesis, low costs, and light color.O‐C3N4 is rich in oxygen‐containing functional groups. [ABSTRACT FROM AUTHOR]

In this work, silicone polymer (PSOL)/carbon fiber (CF)/epoxy (EP) composites were prepared by introducing PSOL as interfacial modifiers into CF/EP composites. The mechanical and dynamic mechanical properties of the composites were investigated, and the optimum content of the PSOL modification was obtained. The impact of EP on the wettability of CF was compared before and after adding PSOL. The micromorphology of CF/EP composites was also observed. The consequences demonstrate that the interfacial bonding ability between CF and matrix was improved after adding PSOL. The interlaminar shear strength, tensile strength, elongation at break and flexural strength of PSOL/CF/EP composites were increased by 23.28%, 18.49%, 38.45% and 11.23%, respectively. Furthermore, the original thermal stability of the composite was preserved after the modification of PSOL. [ABSTRACT FROM AUTHOR]

Incorporation of 2D nanofillers can effectively improve tribological performance of epoxy resin (EP). In this work, two types of 2D nanosheets are incorporated to maximize the tribological performance of EP nanocomposites. On the one hand, nano tungsten disulfide (WS2) was coated on graphene oxide (GO) to form 2D WS2@GO nanosheets before they were incorporated into EP matrix. On the other hand, as a comparison, WS2‐GO hybrid was incorporated into EP matrix by directly mixing to obtain epoxy nanocomposites. Tribological performance of EP composites with 0.1–5 wt% 2D WS2@GO nanosheets and WS2‐GO hybrid are then systematically investigated. It is interestingly observed that the addition of WS2‐GO hybrid at 1 wt% decreases the friction coefficient by 5.4% and the specific wear rate by 67.7% of neat EP; comparatively, adding the 2D WS2@GO nanosheets at 1 wt% presents much higher improvements in reducing the friction coefficient by 24.1% and the specific wear rate by about 96.3% of EP. The formation of transfer film is shown to be responsible for enhancing tribological properties of EP by the hybridization of 2D nano‐WS2 and GO nanosheets. Consequently, it is clear that forming 2D WS2@GO nanosheets is dramatically superior to simply mixing nano WS2 and GO with EP in enhancing tribological performance. [ABSTRACT FROM AUTHOR]

To expand the application of light‐weight and high‐strength polymer matrix composites in the fields of aerospace, shipbuilding and transportation, it has designed and fabricated a new‐type carbon fiber fabric/hollow glass beads/epoxy resin (CFF/HGB/EP) composite with a three‐layer sandwich structure, consisting of an upper composite layer (CFF/EP), core layer (HGB/EP) and lower composite layer (CFF/EP). The effects of the CFF/EP layer and the HGB content on the sandwich composites were explored through a systematic investigation of the mechanical properties and microstructure. The results indicate that the density of the sandwich composite can be reduced to 0.83 g cm−3, while the flexural, impact, and tensile strength of the sandwich composite can be increased by 227%, 156%, and 118% compared with pure epoxy resin, respectively. The great improvement of mechanical properties of the sandwich composite makes its application in various industries more promising. [ABSTRACT FROM AUTHOR]