A new combination rule based on Dezert-Smarandache theory (DSmT) is proposed to deal with the conflict evidence resulting from the non-exhaustivity of the discernment frame. A two-dimensional measure factor in Dempster-Shafer theory (DST) is extended to DSmT to judge the conflict degree between evidence. The original DSmT combination rule or new DSmT combination rule can be selected for fusion according to this degree. Finally, some examples in simultaneous fault diagnosis of motor rotor are given to illustrate the effectiveness of the proposed combination rule. 相似文献
Maintaining the safety and reliability of nuclear engineering materials under a neutron irradiation environment is significant. Atomic-scale simulations are conducted to investigate the mechanism of irradiation-induced vacancy formation in CLAM, F82 H and α-Fe with different neutron energies and objective laws of the effect of vacancy concentration on mechanical properties of α-Fe. Damage of these typical metal engineering materials caused by neutrons is mainly displacement damage, while the displacement damage rate and the non-ionizing effect of neutrons decrease with the increase of neutron energy. The elastic modulus, yield strength, and ultimate strength of α-Fe are in the order of magnitude of GPa. However, the elastic modulus is not constant but decreases with the increase of strain at the elastic deformation stage. The ultimate strength reaches its maximum value when vacancy concentration in α-Fe is 0.2%. On this basis, decreasing or increasing the number of vacancies reduces the ultimate strength. 相似文献
The bias stability of differential interferometric fiber optical gyroscope is analyzed.Thermal error causing long-term bias drift are reduced by putting the 90°splice in the middle of the fiber coil and applying a wide spectrum light source.Also,a kind of novel optical differential processing,which is much more precise than the electronic differential processing,is proposed for reducing the residual nonreciprocal error in the final differential output.An experimental setup based on optical differential processing was built.An~100 fold reduction in the long-term bias drift is demonstrated experimentally compared with the primary differential interferometric fiber optical gyroscope. 相似文献
Unsteady cavitating flow is extremely complicated and brings more serious damages and unignorable problems compared with steady cavitating flow.CFD has become a practical way to model cavitation;however,the popularly used full cavitation model cannot reflect the pressure-change that the bubble experiences during its life path in the highly unsteady flow like cloud cavitating.Thus a dynamic cavitation model(DCM)is proposed and it has been considered to have not only the first-order pressure effects but also zero-order effect and can provide greater insight into the physical process of bubble producing,developing and collapsing compared to the traditional cavitation model.DCM has already been validated for steady cavitating flow,and the results were reported.Furthermore,DCM is designed and supposed to be more accurate and efficient in modeling unsteady cavitating flow,which is also the purpose of this paper.The basic characteristic of the unsteady cavitating flow,such as the vapor volume fraction distribution and the evolution of pressure amplitude and frequency at different locations of the hydrofoil,are carefully studied to validate DCM.It is found that not only these characteristics mentioned above accord well with the experimental results,but also some detailed transient flow information is depicted,including the re-entrant jet flow that caused the shedding of the cavity,and the phenomenon of two-peak pressure fluctuation in the vicinity of the cavity closure in a cycle.The numerical results validate the capability of DCM for the application of modeling the complicated unsteady cavitating flow. 相似文献
The rapid development of flexible triboelectric nanogenerators (TENGs) has become an alternative to batteries for wearable devices. Stretchable, multifunctional, and low-cost are the primary development directions for these wearable devices based on TENG. Herein, a stretchable triboelectric generator with coplanar integration was designed for energy harvesting and force sensing. The industrial conductive silicone and silicone were used to fabricate the TENG with a thickness of less than 0.9 mm. When the elongation was less than 150%, TENG exhibited excellent linear characteristics in the resistance-tensile strain correspondence, and the coefficient of determination was 0.99. This stretchable TENG with a sufficient contact area of 9 cm2 could generate a short-circuit current of 2 μA when it was in contact with the skin. Lastly, an intelligent tension monitoring wearable device that can effectively measure the tensile force was developed. Such a stretchable, coplanar integration-based, and low-cost wearable device has excellent applicability in wearable electronics.
This paper presents the results of an experimental study of the short- and long-term behavior of low-strength reinforced concrete (RC) beams strengthened with carbon fiber reinforced polymer (CFRP). A numerical analysis model was developed and verified for the calculation of the long-term deflection and maximum allowable long-term load of such RC beams. A parametric study was also conducted and it was found that the maximum allowable long-term load of a CFRP-strengthened beam was dominated by the deflection of RC beam when the cubic compressive strength of concrete was less than a certain value. For concrete of higher strength, the maximum allowable long-term load was dominated by the stress levels of the steel bars. It was also found that the yielding load of the strengthened beams increased significantly with areas strengthened by CFRP sheets and steel bars, while the maximum allowable long-term load only increased slightly. 相似文献