Papers by Keyword: Mechanical Parameters

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Authors: Shou Jun Wang, Li Bo Yang
Abstract: Wave-maker mechanical parameters play an important role in the stability of the wave systems. Accurate mechanical parameters are the key part and basic work in the design and analysis of one wave-maker. In order to meet the strength, stiffness and response time requirements, its necessary to have its stress analysed before, which is meaningful to the design of the wave-maker. According to this situation, a caculation method of wave-maker mechanical parameters based on Matlab and Excel is introduced in this paper.
Authors: Yuan Zhao, Liang Qing Wang, Peng Zhou, Yue Han, Guo Rong Chen
Abstract: Rock mass mechanical parameters play a significant role in geotechnical engineering design, slope stability evaluation and numerical simulation, which is commonly determined by GSI method. The simplified method using P-velocity to determine GSI (Geological Strength Index) values is proposed in this study, avoiding the limitations of Hoek-Brown method. The relationship between GSI and P-velocity is established through data collected from several projects in China. Then the dam site of Rumei hydropower station, Tibet, China has been taken as a case study to validate this relationship. This method can be utilized directly in engineering projects since it can meet with the engineering accuracy requirement and reduce the cost.
Authors: Dong Heng Hao, Jian Feng Qi, Bin Wang, Shu Qin Zhao
Abstract: Geotechnical tests are performed to study the strain-stress behavior and mechanical parameters by using the automatic KTG triaxial shear apparatus. This study shows that the strain softening phenomenon emerges after the peak values of strain-stress relations appear for the sliding-body soils, and that the strain-stress relations are in the sate of strain hardening all the time for the sliding-zone soils although the water content keeps sameness. The variation laws of cohesion and internal friction angle with water content are respectively consistent with an exponential function and linear relation.
Authors: Da Wei Jin, Jian Qiao Li, Shi Chao Fan, Hao Li, Yang Wang
Abstract: It is important to analyze mechanical relationship between lunar wheel and lunar soil for studying passing ability of regolith in lunar soil. Mechanical relationship between lunar wheel and regolith could be reflected by these parameters such as sinkage, drawbar pull, driving torque, motion resistance and slip when the lunar wheel moves. Thus, it is necessary to analyze these parameters of lunar wheel by soil bin test. The test results show that, the four parameters increase with slip and loading, except motion resistance of the test wheel which is under 70N at the speed of 25mm/s. The variations of the four parameters are not significantly influenced by velocity. The variations of the four parameters are significantly influenced by loading.
Authors: Wen Hui Tan, Lei Zhang, Dan Qing Gao, Ya Liang Li
Abstract: How the mechanical parameters of rock change with the development of joints and fractures is still a puzzle. It is hard to measure rock joints accurately at present. Resistivity is an important parameter of rock and its value can reflect the degree of fragmentation of rock. A new method combining measurement method of Young’s modulus with resistivity survey method is proposed in this paper. To determine the variation of mechanical parameters in the process of rock damage, the uniaxial, tri-axial compression tests and resistivity survey on rock specimens are done. The results showed that the values of resistivity were continuously increasing, but Young’s modulus and mechanical parameters were decreasing in the process of rock damage. The relationships between resistivity and mechanical parameters are established based on the experiments in the process of rock damage. Therefore, the damage state of rock and the change of mechanical parameters of rock can be determined according to the variance of resistivity. The study is helpful for design and real- time stability evaluation on rock engineering.
Authors: Xiang Hui Deng
Abstract: The in-situ stress is one of important basic data for stability evaluation, engineering design and construction of tunnels. For southwest high mountain region, the in-situ stress in the site test is very difficult. Thus, for satisfying engineering design and construction, it is necessary to back analyze the in-situ stress. The highway tunnel which locates at the 1# road of Lianghekou hydropower station is researched as the object. Based on measured displacements, the inversion model of initial earth stress is built. By comparing the calculated and measured results, the reasonable horizontal pressure parameters and the modulus of elasticity are confirmed.
Authors: Sheng Jie Di, Wen Tang Zheng, Jing Kui Zhang
Abstract: The rock mass with polycrystalline aggregates is common geomaterial in civil and architectural engineering as well as hydraulic and hydro-power engineering. For this kind of geometerials, the study on the joint deformation parameters Kn and Ks and the calculation method are not enough so far. Focusing on the rock mechanics and engineering problems of columnar jointed rock mass related to Baihetan hydropower project, analytical models and numerical method based on 3DEC are employed to study the mechanical parameters. The joint deformation parameters Kn and Ks are back analysis using GRNN and the field data of load-bearing plate tests. The application shows that the calculation results are in good accordance with in-situ test results.
Authors: Jing Sen Liu, Hai Bo Li, Guo Kai Zhang, Jian Deng
Abstract: In order to improve the accuracy of the rock mechanical parameters, the correlations among physical and mechanical parameters were investigated. A large number of laboratory testing results curried out on 408 rock specimens including metamorphic rocks, sedimentary rocks and igneous rocks. Through the statistical analysis of the laboratory test data, several regression equations among rock material parameters were established. The research suggests that, in addition to Poisson's ratio, the mechanical parameters (unconfined compressive strength (UCS), elastic Young’s modulus, shear modulus) relate well to physical parameters (porosity, P-wave velocity), and the relationships are mainly described by power and exponential correlations which have good squared regression coefficients. The correlation between elastic Young’s modulus and dynamic elastic modulus was established, as well as the relationship between shear modulus and dynamic shear modulus.
Authors: Ondřej Holčapek, Pavel Reiterman, Marcel Jogl, Petr Konvalinka
Abstract: The main aim of this contribution lies in the description of mechanical properties fiber cement composites after exposure to high temperatures. Destructive and non-destructive methods were used to investigate the influence of heat loading. The effect of refractory binder compared to common Portland cement binder was observed. Widespread non-destructive testing method can describe the changes of mechanical properties due to influence of external load e.g. high temperature at the level of 1000 °C. The tensile strength and compressive strength were investigated on specimens 40 x 40 x 160 mm. Before these destructive tests dynamic modulus of elasticity and tentative compressive strength were provided.
Authors: Zbigniew L. Kowalewski, Sławomir Mackiewicz, Jacek Szelażek
Abstract: Damage development due to creep under uniaxial tension at elevated temperatures is assessed using destructive and non-destructive methods in steels, commonly used in power plants or chemical industry, and in aluminium alloy used in aircrafts for responsible elements. The results obtained using two different destructive methods for assessments of damage development are critically discussed. In the first method the specimens of steel after different amounts of creep prestraining were stretched up to failure and variations of the selected tension parameters were taken into account for damage identification. In the second one, a damage degree was evaluated by studying variations of an initial yield locus position in the stress space and by determination of the yield loci dimensions. The ultrasonic investigations were selected as the non-destructive method for damage development evaluation.
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