Papers by Keyword: Shear Property

Abstract: The shear property of bonding interface between new and old concrete with bonding-in reinforcement was researched. The shear experiment was done to 6 groups with 18 specimens with 5 interface agent types of casting new concrete directly, painting neat cement, painting merchandise agent and with bonded-in reinforcement. The shear properties of bonding interface were analyzed, and the shear strengths were compared with each other. The experiment results show that the shear strength of the interface could be enhanced remarkably with bonded-in reinforcement. The practical calculation formula was proposed, considering the influence of interface roughness, agent and bonded-in reinforcement. In the end, the formula was validated by other experiment and could be used in the strengthening design for concrete structure.

Abstract: The shear property of the thermoelectric material Bi₂Te₃ is inextricably linked with its layer structure. By the molecular dynamics method, the mechanism of shearing deformation was studied in this paper. In the simulation, cubic single-crystal simulation cells with different layer directions inside were adopted, ensuring that the c axis of crystal lattice can be along, across and 45^o deviated from the shear stress. Compared with all the calculation models, the results show that when the shear stress increases, slip occurs along the Te1-Te1 adjacent layers which are connected by the weak van der Waals bonding, and ultimately leads to structural fracture. Furthermore, size effect and loading modes can also impact the behavior of shearing deformation, however, in very different ways. Future efforts should be focused on the influence of the creation and motion of defects during the deformation as well as temperature effect and strain rate effect.

Abstract: Three different panel density of sandwich composites were designed. The composite was reinforced by spacer fabric woven with polyester filaments, fiiled by polyurethane foam in the space of the fabric and composite the epoxy resin on the surface of the fabric. The effects of different panel density on the mechanical properties of sandwich composite were tested,including the shear property and peel property. The results showed that the panel density have some effects on the mechanical properties. Shear and peel property increased with the panel density increased.

Abstract: The structure of corn stubble was complex and closely combined with the soil, so dig location and root-soil separation are the urgent problem of the manufacturing of corn stubble harvesting machinery. This paper mainly focuses on investigating the interaction principles of corn stubble and soil which by the UU triaxial compression tests. Compared the shear strength of three different types of corn root-soil complexes (vertical root, horizontal root, complex root) and pure soil, and analyzed three important factors affecting the root-soil complex shear strength, it was shown that the presence of corn fibrous root can enhance the soil shear strength and different with their layout types. It will provide a theoretical basis for the design of bionic agricultural tillage components for root- soil separation.

Abstract: The powder with size distribution was made from eruption to be used for the simulant of lunar soil. One of the most important factors is shear property, to simulate lunar soil behavior under the rover wheels. Therefore, it is necessary to measure the shear parameters of the simulant. The direct shear detector with controlled sample weight was used for selecting suitable method to obtain the shear parameters of the simulant, and finding effect actors for the measurement. Results found that the parameters changed greatly with the powder bulk density (or unit weight), and the calibration was vitally important for measuring cohesion of the powder.

Abstract: The survey shows that the bulk density of lunar soil increases with the depth. The compaction of lunar soil also differs in the depth. The lunar soil mechanical condition plays an important and non-negligible roll on the mobility of the rover. It is important to make research on the change of the mechanical parameters at different lunar soil conditions, and it is also important to research the trafficability of rover on different lunar surface condition. The presented paper simulates the lunar soil with different depth by means of three kinds of lunar soil simulant on different compact condition. Based on the direct shear apparatus, it was researched that the cohesion, internal friction angle, bull density of lunar soil simulant on different compaction conditions, including loose, normal, and compressed. The measurement results show that the bulk density and cohesion of the lunar soil simulant increase with the compact conditions in general. The bulk density changes within a narrow range from1.1 g/cm³ to 1.4 g/cm³. The cohesion increases, and changes significantly, which varies from 0 kPa to 0.5 kPa. The internal friction angle changes without regularity within a range from 30 deg to 40 deg. The measurement results can be used to explain the different trafficability of wheels after repeatedly passing the same lunar surface. Also it will be of significant to the evaluation of the rover mobility at different lunar soil condition.

Abstract: In this study, by changing Z-pin’s insertion parameters, the X-cor sandwich was prepared with vacuum curing molding process. The effects of Z-pin’s insertion angle, insertion density and diameter on compression, shear and tension properties were studied. The results show that Z-pin’s insertion parameters can significantly affect the mechanical properties of X-cor sandwich. The compression properties of X-cor sandwich are reduced, while shear properties are improved by the increase of Z-pin’s insertion angle. As Z-pin’s insertion angle increases the tension modulus increases while the tension strength firstly increases and secondly decreases. The mechanical properties increase with the increase of Z-pin’s insertion density and diameter. Compared with the foam core sandwich, the mechanical properties of X-cor sandwich are significantly improved in both modulus and strength.