Papers by Author: Yue Wu

Abstract: We choose three plant esterase sources, through the measurement of enzyme activity , the plant esterase that sieved efficiently withdraws the raw material, and as to it's the crude extract of the esterase to suggest the reaction condition of the liquid to carry on the system excellent turn, such as pH, reaction time and dilution. So we can guarantee the enzyme inhibition represses the method in great quantities takes out to check the sample carries on the quickly thick of accurate degree, also soon measures the card for the fixed and organ phosphorus pesticide of thorough study to provide the reference.

Abstract: Studies on the characteristics of the mean wind load acting on the cantilevered roofs are carried out systematically by CFD (Computational Fluid Dynamics) numerical simulation. The influences of some factors, including the incoming flow condition, inclination angle of roofs and the ventilation rate above grandstand, on mean wind loading are investigated. It is found that the terrain type and grandstand type are not significantly influence the mean wind loads on the roof structure; The wind force acting on roof is increased with roof pitch; Sub-roof venting is found to reduce uplifts by no more than 12%; Introducing a similar shaped grandstand upstream is found to significantly decrease the wind loading. Based on these results, an empirical equation for the calculation of mean wind loading is derived for the reference of designers.

Abstract: A number of methods for assessing wind-induced vibration of structures are available ranging from simplified procedure using quasi-static methods to the detailed procedure using statistical methods. The appropriate procedure should be selected in accordance with wind sensitivity of structures. However, it still remains unresolved concerning how to provide a universal criterion with physically meaningful and convenient for the concept of the wind sensitivity until now. In order to solve the previous problem of how to distinguish between those structures for which the wind effects can be treated by simplified procedure, and those for which the wind effects must be treated by detailed procedure, a concept of sensitivity for wind-resistance is presented in this paper. The essential idea of this theory is to provide a general expression of wind sensitivity of structures by synthesizing three factors between wind load and the structure, including the size-effect factor, frequency-effect factor and mode-effect factor, which are based on the analytical derivation and take duly into account the influence of all the significant parameters for the response. Based on that, two case studies of cantilevered roof and single-layer reticulated shell structures under wind actions are demonstrated as illustrative examples.

Abstract: Characteristics of wind pressure distributions over the spherical shell with 3/4 rise-span ratio have been investigated based on the data obtained from a wind tunnel experiment. A discussion of the spectral characteristics including shape of wind pressure spectra, reduced frequency corresponding to the peak spectral amplitude, and spectral slope in high frequency range is also made. The results show that the normalized pressure spectra has a broadband peak at a reduced frequency between 0.15 and 0.50, the slope of Sp( f ) in a high frequency range varies from -1.85 to -0.30 and the reduced peak frequency depends on the tapping locations. Though spectral patterns change from place to place, standard normalized spectra associated with various zones of spherical shell could be appropriately classified based on identical spectral characteristics. On this basis, an empirical spectral equation is figured out including three parts which represent the contribution of approach turbulence, turbulence induced by separation on the top of spherical shell and wake turbulence respectively. The accuracy of model is verified by comparison with the measured spectra results.

Abstract: Taking Harbin west railway station as the researching object, the wind load distribution as well as its effects, which are widely used in practice, is investigated. First, wind pressure distribution on a rigid model is measured simultaneously in a wind tunnel. Some special characteristics of the measured wind pressure, especially its fluctuating component, are discussed. Then the fluctuating wind pressure field is reconstructed based on the synchronous multi-pressure scanning technique of wind tunnel tests and the proper orthogonal decomposition (POD) technique. The influence of lower RC structure on wind-induced vibration is investigated using non-linear time-history analysis. At last, a new method is introduced to obtain equivalent static wind load (ESWL) that reproduce all largest load effects at the same time. With the synthetic application of above methods, the problems such as: complex time and spatial distribution of fluctuating wind; multi-mode vibration of wind-induced response; multiple equivalent objectives for ESWL, can be solved efficiently.