Papers by Keyword: Mechanical Characteristic

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Authors: Hee Jae Shin, Lee Ku Kwac, Sun Ho Ko, Tae Hoon Kim, Hong Gun Kim
Abstract: Of the advanced composite materials for aerospace structures such as aircrafts and space devices, the carbon fiber reinforced plastics (CFRP) is applied to many sectors that require lightweight materials for its high strength and stiffness. One of the disadvantages of the CFRP, however, is that it is weak against impact. In this study, impact test specimens were manufactured with five fiber stacking angles (0°/0°, 0°/15°, 0°/30°, 0°/45°, 0°/90°) according to ASTM D7136[15], and a falling weight test was performed to analyze the correlation between their mechanical and thermal characteristics. As a result, the impact energy applied to the five test specimens with different fiber stacking angles was almost constant at 30.63 J - 30.78 J. The absorbed energy increased with the increase in the fiber stacking angle, and decreased after 0°/45°. The average temperature on the fractured surface increased with the increase in the fiber stacking angle in all specimens other than the 0°/0° specimen.
Authors: Hee Jae Shin, In Pyo Cha, Min Sang Lee, Tae Ho Kim, Hyun Kyung Yun, Lee Ku Kwac, Hong Gun Kim
Abstract: The fiber is considered the most important element in fiber reinforced composite materials, as it generally occupies the largest volume in a composite material; further, delivers the heaviest loads. therefore, it is important to select types, quantity and proper stacking angles of the fiber. In this study, the fiber directions were arranged in different orientation angles, i.e. in symmetric (0°/0°,15°/15°,30°/30°,45°/45°,90°/90°) and asymmetric (0°/15°,0°/30°,0°/45°,0°/90°), to analyze the tensile strengths depending on the fiber orientation angles through the tensile test. In addition, a thermal imaging camera was used to investigate the thermal characteristics of the test specimens generated during the tensile test. the tensile strength showed a tendency of decreasing while the orientation angle increased. the maximum temperature generated when the fracture occurred increased at the fiber orientation angle of 30°, and showed a tendency of decreasing as the orientation angle increased.
Authors: Sun Hee Kim, Soon Jong Yoon, Won Chang Choi
Abstract: In this paper, the results of experimental and analytical investigations pertaining to the structural behavior of glass fiber reinforced polymer plastic (GFRP) pipes are presented. GFRP is assumed as an orthotropic material. Mechanical properties along the longitudinal and hoop direction of the pipes are determined by the tension and compression tests. The parallel plate loading tests for the GFRP pipes were conducted to findthe relation between load and ring deflection. Inaddition, the finite element analysis (FEA) for the GFRP pipes was conducted using the material properties obtained from test in the study. The numerical results obtained by the finite element method show good agreement with the parallel plate loading test results for GFRP pipes.
Authors: Peng Zheng, Duo Zuo, Yuan Hui Wang
Abstract: We design a set of milling head test series in order to test the properties of the A/C double angular milling head. The article gives the primary test method as a comprehensive test for the whole series’ property, precision, stiffness, and mechanical performance to make the milling head excellent property.
Authors: Miao Shang, Guo Min Lin, Wen Guang Zhang, Jiao Jiao Ye
Abstract: The functional relationship is analyzed between three-phase asynchronous motor electromagnetic torque and some factors; Mechanical characteristic curve of motor performance is drawn; The inherent mechanical properties and human mechanical properties are explored in a specific application. Facts prove that mechanical characteristic analysis of three-phase asynchronous motors, to reduce the failure rate of the three-phase induction motor, to improve the running capacity and production efficiency are important.
Authors: Gui Lan Zhang, De Xu Geng
Abstract: This paper has introduced the structure of elongational pneumatic artificial muscle, analyzed axial mechanics characteristics of elongation artificial muscle, established the axial mechanics model, verified the credibility of the model through the experiment.
Authors: Liana Paraianu, Dorel Banabic
Abstract: The current trend in the automotive industry consists in decreasing the weight of the car body to reduce the fuel consumption and the air pollution. This can be done by using low-density materials such as the aluminium alloys having good formability. A frequently used aluminium alloy in the manufacturing of the car body components is AA6016-T4. The paper presents a full mechanical characterization of this material with 1 mm thickness. The investigation starts by performing tensile tests on specimens cut at 0o, 45o and 90o from the rolling direction. For each direction, the yield stress and the anisotropy coefficients are determined. The mechanical parameters of the Hollomon hardening law are determined using the experimental data obtained on samples cut along the rolling direction. Besides the uniaxial parameters, the equibiaxial yield stress and the equibiaxial coefficient of anisotropy are determined by performing bulge tests and compression tests, respectively. The yield surface is characterized in the first quadrant not only by the uniaxial and equibiaxial yield stresses but also by the yield stresses associated to the plane strain status. An experimental strategy for determining the plane strain parameters based on bulge tests is described in the paper. The characterization of the AA6016-T4 aluminium alloy ends with the determination of the forming limit diagram. The tests used for determining the limit strains are the punch stretching and hydraulic bulging.
Authors: Radu Saulescu, Mircea Neagoe, Codruta Jaliu, Olimpiu Munteanu
Abstract: Planetary transmissions used as speed amplifiers in wind/hydro conversion systems typically rely on the conventional concept of mechanism with one input and one output. This concept is found in the most of the high power wind turbines; however, the need to implement in the built environment smaller wind turbines with speed amplifiers led to new turbine concepts such as counter-rotating rotors and classical generator. The paper presents a comparative analysis of two wind turbines with one rotor and respectively two counter-rotating rotors, which contain identical electrical generators and the same type of mechanical amplifier used as a 1 DOF mechanism and differential one respectively. With the assumption of maintaining the same electrical generator running point for both wind turbines, the steady-state behaviour of the considered turbines is identified and a comparative kinematic and static performance analysis is performed, aiming at highlighting the impact on efficiency and on constructive design and development of the two turbines.
Authors: Hui Mei Zhang, Geng She Yang
Abstract: Considering the heterogeneous characteristics of rock at mesoscopic level, the damage propagation constitutive relation and evolution equation of freeze-thaw and loaded rock were established by using the theory of macro phenomenological damage mechanics and the generalized theory of strain equality. The evolutionary mechanisms of micro-structural damage and materials mechanical properties for the loaded rock were discussed under freeze-thaw condition, verified by experimental results of the freeze-thaw cycle and compression test of rock. It is shown that the freeze-thaw and loaded damage model can represent the complicated relations among the freeze-thaw, load and the damage inside the rock, reveal the coupling failure mechanism of macroscopic rock under the freeze-thaw and load from the micro-damage evolution. The combined effect of freeze-thaw and load exacerbates the total damage of rock with obvious nonlinear properties, but the coupling effect weakens the total damage. The lithology and initial damage state of the freeze-thaw and loaded rock in engineering structures in cold regions determine the weights of influence factors to mechanical properties, including environmental factor, loading factor and the coupling effects, so the rock performances different damage mechanical characteristic.
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