Papers by Keyword: Experimental Study

Abstract: In order to meet the needs of underground engineering, a new type of basalt fiber reactive powder concrete (BFRPC) was developed in this paper. In different materials ratio, the mechanical properties of BFRPC were studied by experimental methods. And compressive strength and bending strength of BFRPC were obtained. The optimal fiber content of BFRPC was got, and the stress-strain relationship was revealed. It would lay the foundation for the application of BFRPC materials in underground engineering.

Abstract: This paper presents the results of an experimental study of the possibility of high-entropy oxide phases creation using the of solid-phase synthesis method in the Al₂O₃–BaO–CuO–Fe₂O₃–Mn₂O₃–NiO–SrO–TiO₂–ZnO and Al₂O₃–BaO–CuO–Fe₂O₃–NiO–SrO–TiO₂–WO₃–ZnO systems. As a result of the study, a microcrystalline octahedral multicomponent phase was found in the crystallized sample. Judging by the composition, this phase has a spinel structure and is characterized (judging by the components concentrations and its ratio) by rather high values of the mixing configurational entropy. It is shown that barium, strontium and tungsten are not included in this phase in appreciable amounts. The obtained results indicate the possibility of synthesizing high-entropic spinels using these Al₂O₃–CuO–Fe₂O₃–Mn₂O₃–NiO–TiO₂–ZnO systems.

Abstract: In order to study the dynamic characteristics of an innovative underwater structure, Submerged Floating Tunnel (SFT), a model test study was carried out in a calibrated experimental tank based on the Qiongzhou Strait cross-sea passage project and considering the effects of wave and current loads. The size of the test tank is 36m (length) x 31m (width) x 3m (depth), which can simulate the effect of wave and current simultaneously. Under the conditions of pure current, pure wave and wave-current coupling, the pressure change of the test pipe is monitored, and the influence of the wave-current load on the surface pressure of the test pipe is analyzed. The experimental results show that the pressure at the inlet side of the test pipe increases with the increase of the current velocity, the wave height and period, regardless of whether the test pipe section is subjected to pure current, pure wave or wave-current coupling.

Abstract: In this paper, test method of half-section small-scale model with indoor undisturbed soil is used to study the effect of difference disc forms on bearing mechanism of concrete disc piles and soil failure state around piles under horizontal force. The model piles with different disc cross-section forms were designed under the condition of undisturbed soil, and loading test was carried out to analyze soil failure state around the pile. The results show that: under the action of horizontal force, soil around the pile is cracked along the midline; asymmetric bearing disc is more reasonable than symmetrical bearing disc. The minimum load difference between the disc end fillet and the disc tip fillet is less than 5%. The curved end of bearing disc has little effect on the horizontal bearing capacity of concrete expanded disc pile.

Abstract: The article presents the results of numerical and experimental studies of stress-strain curves of 1D-reinforced polymer composite materials based on hollow porous fibers and epoxy matrix. The two-scale nature of the composite under research was taken into account. A surrogate easily parameterized model based on Bezier curves was developed and used to approximate the stress-strain curve of ductile material. The calculations were performed using reversible homogenization and finite element methods, which were implemented in computational subsystem of DCS GCD. Representative volume elements of the investigated materials were created using the geometry generating subsystem of DCS GCD. Test samples were made using three-axis milling machine and compression tests were carried out. Computational results of effective stress-strain curves determination were obtained and compared with experiments.

Abstract: The paper presents the experimental study results of a multicomponent phase with M-type hexaferrite structure obtaining. The synthesis method of the BaO–PbO–SrO–CaO–ZnO–Fe₂O₃–Mn₂O₃–Al₂O₃ system melt was used. As a result of the study, microcrystalline octahedral and hexagonal phases were found in the crystallized sample. The hexagonal one, judging by the chemical composition, is a multicomponent phase with the structure of M-type hexaferrite (Ba/Sr/Ca) (Fe/Mn/Al)₁₂O₁₉, which is characterized (judging by the concentrations of the components) by rather high values of configurational mixing entropy. It was shown that lead is practically absent in the crystallized phase composition. The zinc content is unstable. Obviously, lead oxide in used experimental conditions, goes into the composition of the gas phase. The question of the possibility of using zinc as a component of the hexaferrite phase deserves further careful study.

Abstract: A metal rubber damper was designed for the too large impact response of a product. The impact response of products which bears big shocks with and without metal rubber damper were studied and compared. The damping performance of the metal rubber damper with different pre-compression was tested and studied. The test results show that the metal rubber damper can effectively reduce the impact response of the product in three directions; The damping effect of cylindrical metal rubber damper in the direction of cylinder axis is better than that in the other two axial directions; different pre-compression amounts have great influence on the impact response, so the optimum damping effect is obtained by adjusting the pre-compression amount of the metal rubber damper.

Abstract: The results of experimental studies of combined beams consisting of a stone part, reinforced with side reinforced concrete plates are given. Experimentally shown the viability of the proposed structures. The conditions for ensuring the combined action of a stone beam and a reinforced concrete plate are given. Cases are shown when one-sided plates can be used and when double-sided reinforced concrete plates can be used. A comparison of experimental data with the data calculated by the authors developed methods is given. A good agreement between theoretical and calculated data is shown.

Abstract: A series of connection with screw fasteners were tested to study the behavior of cold-formed steel moment connection. The test specimens included hot-rolled parallel flange channels, cold-formed lipped C-Channels, and self-drilling self-fastening screws. Two different lipped C-Channels and a various number of screws per connection were used in this study. The moment-rotation behavior, rotational rigidity, and the connection capacity differed with the number of screws. The connection behaved as a pinned connection when 4 screws were used. However, local buckling was observed in the cold-formed steel sections near the connection when 8, 10 and 14 screws were used. The connection test results were compared with theoretical results calculated in accordance to the Australian Standards. None of the connection tested could achieve the moment capacity of the section connected.

Abstract: This paper presents the experimental results given by the operation of a chemical sorption refrigeration system using Expanded Graphite/Activated Carbon/Lithium Chloride (AC/GE/LiCl)-Adsorbent (NH₃ in solution with a 25% concentration). Experimental protocol with the characteristics of the experimental rig developed, working pair specifications and the procedure that has developed in the process is described in detail. Results are presented for different behaviors of the system, where the desorption stage is driven by forced convection. Measurements of the thermal variables of the system show that the adsorption-desorption cycles in the test accomplished, with high and low-pressure zones clearly defined. The cooling effects for the pair material studied have the expected behavior for the mixture proposed.