A novel periodic mount was presented. A theoretical model was developed to describe the dynamics of wave propagation in the novel periodic mount. The model was derived using Hamilton's energy conservation principl...A novel periodic mount was presented. A theoretical model was developed to describe the dynamics of wave propagation in the novel periodic mount. The model was derived using Hamilton's energy conservation principle. The characteristics of wave propagation in unit cell were analyzed by transfer matrix formulation. Numerical examples were given to illustrate the effectiveness of the periodic mount. The experiments were carried out to identify the predications of the theoretical model. The obtained results show that the experimental results coincide with the prediction of theoretical model. No pass bands appear in the overall frequency range measured when waves propagate in the longitude direction of the periodic mount. These dramatic results demonstrate its potential as an excellent mount in attenuating and isolating vibration transmission.展开更多
Deepwater deployment of offshore structures in different sea states was investigated. The whole deployment system was modeled as a lumped mass model, and discretization scheme for cable geometry and methodology for ca...Deepwater deployment of offshore structures in different sea states was investigated. The whole deployment system was modeled as a lumped mass model, and discretization scheme for cable geometry and methodology for calculating the internal and external force acting on deploying cable were presented. The deployment model suitable for the time-varying length of deploying cable was specified. The free-surface flow fields together with the ship motions were used to calculate dynamic tension in the deploying cable during deployment of the structure. The deployment of deep sea mining system which was a typical subsea working system was employed. Based on lumped mass analysis model and parameters of deep sea mining system, numerical simulations were performed, and dynamic load and dynamic amplification factor(DAF) with different cable parameters, deploying velocities and sea states were obtained. It is shown that cable parameters and amplitudes of ocean waves can significantly influence the dynamic load and DAF, and the time-varying natural period of deploying system is a dominant factor, while the effect of deploying velocity is not obvious.展开更多
Natural ventilation is driven by either buoyancy forces or wind pressure forces or their combinations that inherit stochastic variation into ventilation rates. Since the ventilation rate is a nonlinear function of mul...Natural ventilation is driven by either buoyancy forces or wind pressure forces or their combinations that inherit stochastic variation into ventilation rates. Since the ventilation rate is a nonlinear function of multiple variable factors including wind speed, wind direction, internal heat source and building structural thermal mass, the conventional methods for quantifying ventilation rate simply using dominant wind direction and average wind speed may not accurately describe the characteristic performance of natural ventilation. From a new point of view, the natural ventilation performance of a single room building under fluctuating wind speed condition using the Monte-Carlo simulation approach was investigated by incorporating building facade thermal mass effect. Given a same hourly turbulence intensity distribution, the wind speeds with 1 rain frequency fluctuations were generated using a stochastic model, the modified GARCH model. Comparisons of natural ventilation profiles, effective ventilation rates, and air conditioning electricity use for a three-month period show statistically significant differences （for 80% confidence interval） between the new calculations and the traditional methods based on hourly average wind speed.展开更多
A novel quantitative structure-property relationship （QSPR） model for estimating the solution surface tension of 92 organic compounds at 20℃ was developed based on newly introduced atom-type topological indices. Th...A novel quantitative structure-property relationship （QSPR） model for estimating the solution surface tension of 92 organic compounds at 20℃ was developed based on newly introduced atom-type topological indices. The data set contained non-polar and polar liquids, and saturated and unsaturated compounds. The regression analysis shows that excellent result is obtained with multiple linear regression. The predictive power of the proposed model was discussed using the leave-one-out （LOO） cross-validated （CV） method. The correlation coefficient （R） and the leave-one-out cross-validation correlation coefficient （Rcv） of multiple linear regression model are 0.991 4 and 0.991 3, respectively. The new model gives the average absolute relative deviation of 1.81% for 92 substances. The result demonstrates that novel topological indices based on the equilibrium electro-negativity of atom and the relative bond length are useful model parameters for QSPR analysis of compounds.展开更多
To solve the problems of divergence,low accuracy and project application of membrane wrinkling analysis,an analysis method of zero shear modulus and equivalent stiffness was proposed.This method is an improvement to t...To solve the problems of divergence,low accuracy and project application of membrane wrinkling analysis,an analysis method of zero shear modulus and equivalent stiffness was proposed.This method is an improvement to the previous method (Method I) of local coordinate transposition and stiffness equivalence.The new method is derived and the feasibility is theoretically proved.A small-scale membrane structure is analyzed by the two methods,and the results show that the computational efficiency of the new method (Method II) is approximately 23 times that of Method I.When Method II is applied to a large-scale membrane stadium structure,it is found that this new method can quickly make the second principal stress of one way wrinkled elements zero,and make the two principal stresses of two-way wrinkled elements zero as well.It could attain the correct load responses right after the appearance of wrinkled elements,which indicates that Method II can be applied to wrinkling analysis of large-scale membrane structures.展开更多
基金Project(50775225) supported by the National Natural Science Foundation of China
文摘A novel periodic mount was presented. A theoretical model was developed to describe the dynamics of wave propagation in the novel periodic mount. The model was derived using Hamilton's energy conservation principle. The characteristics of wave propagation in unit cell were analyzed by transfer matrix formulation. Numerical examples were given to illustrate the effectiveness of the periodic mount. The experiments were carried out to identify the predications of the theoretical model. The obtained results show that the experimental results coincide with the prediction of theoretical model. No pass bands appear in the overall frequency range measured when waves propagate in the longitude direction of the periodic mount. These dramatic results demonstrate its potential as an excellent mount in attenuating and isolating vibration transmission.
基金Project(51305463) supported by the National Natural Science Foundation of China
文摘Deepwater deployment of offshore structures in different sea states was investigated. The whole deployment system was modeled as a lumped mass model, and discretization scheme for cable geometry and methodology for calculating the internal and external force acting on deploying cable were presented. The deployment model suitable for the time-varying length of deploying cable was specified. The free-surface flow fields together with the ship motions were used to calculate dynamic tension in the deploying cable during deployment of the structure. The deployment of deep sea mining system which was a typical subsea working system was employed. Based on lumped mass analysis model and parameters of deep sea mining system, numerical simulations were performed, and dynamic load and dynamic amplification factor(DAF) with different cable parameters, deploying velocities and sea states were obtained. It is shown that cable parameters and amplitudes of ocean waves can significantly influence the dynamic load and DAF, and the time-varying natural period of deploying system is a dominant factor, while the effect of deploying velocity is not obvious.
文摘Natural ventilation is driven by either buoyancy forces or wind pressure forces or their combinations that inherit stochastic variation into ventilation rates. Since the ventilation rate is a nonlinear function of multiple variable factors including wind speed, wind direction, internal heat source and building structural thermal mass, the conventional methods for quantifying ventilation rate simply using dominant wind direction and average wind speed may not accurately describe the characteristic performance of natural ventilation. From a new point of view, the natural ventilation performance of a single room building under fluctuating wind speed condition using the Monte-Carlo simulation approach was investigated by incorporating building facade thermal mass effect. Given a same hourly turbulence intensity distribution, the wind speeds with 1 rain frequency fluctuations were generated using a stochastic model, the modified GARCH model. Comparisons of natural ventilation profiles, effective ventilation rates, and air conditioning electricity use for a three-month period show statistically significant differences （for 80% confidence interval） between the new calculations and the traditional methods based on hourly average wind speed.
基金Projects(20775010,21075011) supported by the National Natural Science Foundation of ChinaProject(2008AA05Z405) supported by the National High Technology Research and Development Program of China+2 种基金Project(09JJ3016) supported by Hunan Provincial Natural Science Foundation,ChinaProject(09C066) supported by Scientific Research Fund of Hunan Provincial Education Department,ChinaProject(2010CL01) supported by the Foundation of Hunan Provincial Key Laboratory of Materials Protection for Electric Power and Transportation,China
文摘A novel quantitative structure-property relationship （QSPR） model for estimating the solution surface tension of 92 organic compounds at 20℃ was developed based on newly introduced atom-type topological indices. The data set contained non-polar and polar liquids, and saturated and unsaturated compounds. The regression analysis shows that excellent result is obtained with multiple linear regression. The predictive power of the proposed model was discussed using the leave-one-out （LOO） cross-validated （CV） method. The correlation coefficient （R） and the leave-one-out cross-validation correlation coefficient （Rcv） of multiple linear regression model are 0.991 4 and 0.991 3, respectively. The new model gives the average absolute relative deviation of 1.81% for 92 substances. The result demonstrates that novel topological indices based on the equilibrium electro-negativity of atom and the relative bond length are useful model parameters for QSPR analysis of compounds.
基金Project(020940) supported by the Natural Science Foundation of Guangdong Province,China
文摘To solve the problems of divergence,low accuracy and project application of membrane wrinkling analysis,an analysis method of zero shear modulus and equivalent stiffness was proposed.This method is an improvement to the previous method (Method I) of local coordinate transposition and stiffness equivalence.The new method is derived and the feasibility is theoretically proved.A small-scale membrane structure is analyzed by the two methods,and the results show that the computational efficiency of the new method (Method II) is approximately 23 times that of Method I.When Method II is applied to a large-scale membrane stadium structure,it is found that this new method can quickly make the second principal stress of one way wrinkled elements zero,and make the two principal stresses of two-way wrinkled elements zero as well.It could attain the correct load responses right after the appearance of wrinkled elements,which indicates that Method II can be applied to wrinkling analysis of large-scale membrane structures.
