The spatial variability of geotechnical earthquake engineering critical parameters obtained by laboratory and in situ tests in the same area is affected by different measurements. The paper provides a brief synthesis ...The spatial variability of geotechnical earthquake engineering critical parameters obtained by laboratory and in situ tests in the same area is affected by different measurements. The paper provides a brief synthesis of ground motion and site effects analysis procedures within a Performance-Based Design framework. In particular it focuses about the influence on the evaluation of site effects in some active regions by different shear waves velocity measurements （Down Hole D-H and Seismic Dilatometer Marchetti Test SDMT）. Moreover the variation of shear modulus and damping ratio with strain level and depth from different laboratory dynamic or cyclic tests for soil characterisation （Resonant Column Test RCT） was evaluated. The available data enabled one to compare the shear waves velocity profile obtained by laboratory and in situ tests （Cone Penetration Tests CPT） with empirical correlations proposed in literature.展开更多
An analytical method is developed for the hydroelastic interaction between surface incident waves and a thin elastic plate of arbitrary geometry floating on an inviscid fluid of finite depth in the framework of linear...An analytical method is developed for the hydroelastic interaction between surface incident waves and a thin elastic plate of arbitrary geometry floating on an inviscid fluid of finite depth in the framework of linear potential flow.Three kinds of edge conditions are considered and the corresponding analytical representations are derived in the polar coordinate system.According to the surface boundary conditions,the fluid domain is divided into two regions,namely,an open water region and a plate-covered region.With the assumption that all the motion is time-harmonic,the series solutions for the spatial velocity potentials are derived by the method of eigenfunction expansion.The matching conditions for the continuities of the velocity and pressure are transformed by taking the inner products successively with respect to the vertical eigenfunction for the free surface and the angular eigenfunction.A system of simultaneous equations,including two edge conditions and two matching conditions,is set up for deriving the expansion coefficients.As an example,numerical computation for the expansion coefficients of truncated series is performed for an elliptic plate.The results show that the method suggested here is useful to revealing the physical features of the gravity wave scattering in the open water and the hydroelastic response in the plate.展开更多
The shock wave standoff distances of near space hypersonic vehicles, which execute missions mainly at the altitude of 25 km to 55 km, are vital in aerothermodynamic analysis. The implicit finite volume schemes are der...The shock wave standoff distances of near space hypersonic vehicles, which execute missions mainly at the altitude of 25 km to 55 km, are vital in aerothermodynamic analysis. The implicit finite volume schemes are derived from axisymmetric Navier-Stokes equations for chemical equilibrium flow, and programmed in FORTRAN. Taking a sphere cone for example, the effects of Much numbers （from 22 to 36） on the shock wave standoffdistance and the average density behind the shock are simulated at different altitudes from 25km to 55km. The numerical results illustrate that the turning point of the standoff distance is corresponding to that of the average density with the variation of Mach numbers. Based on the numerical results, we propose a formula for shock wave standoff distance, which is the function of the radius of the blunt body, the Mach number and the altitude in the atmosphere. Compared with previous correlations, the new formula can overcome the drawbacks of larger relative errors and complex calculations of the average density.展开更多
文摘The spatial variability of geotechnical earthquake engineering critical parameters obtained by laboratory and in situ tests in the same area is affected by different measurements. The paper provides a brief synthesis of ground motion and site effects analysis procedures within a Performance-Based Design framework. In particular it focuses about the influence on the evaluation of site effects in some active regions by different shear waves velocity measurements （Down Hole D-H and Seismic Dilatometer Marchetti Test SDMT）. Moreover the variation of shear modulus and damping ratio with strain level and depth from different laboratory dynamic or cyclic tests for soil characterisation （Resonant Column Test RCT） was evaluated. The available data enabled one to compare the shear waves velocity profile obtained by laboratory and in situ tests （Cone Penetration Tests CPT） with empirical correlations proposed in literature.
基金supported by the National Natural Science Foundation of China (Grant No. 11072140)the State Key Laboratory of Ocean Engineering (Shanghai Jiao Tong University) (Grant No. 0803)+1 种基金the Innovation Program of Shanghai Municipal Education Commission (Grant No.09YZ04)The Shanghai Program for Innovative Research Team in Universities is also acknowledged
文摘An analytical method is developed for the hydroelastic interaction between surface incident waves and a thin elastic plate of arbitrary geometry floating on an inviscid fluid of finite depth in the framework of linear potential flow.Three kinds of edge conditions are considered and the corresponding analytical representations are derived in the polar coordinate system.According to the surface boundary conditions,the fluid domain is divided into two regions,namely,an open water region and a plate-covered region.With the assumption that all the motion is time-harmonic,the series solutions for the spatial velocity potentials are derived by the method of eigenfunction expansion.The matching conditions for the continuities of the velocity and pressure are transformed by taking the inner products successively with respect to the vertical eigenfunction for the free surface and the angular eigenfunction.A system of simultaneous equations,including two edge conditions and two matching conditions,is set up for deriving the expansion coefficients.As an example,numerical computation for the expansion coefficients of truncated series is performed for an elliptic plate.The results show that the method suggested here is useful to revealing the physical features of the gravity wave scattering in the open water and the hydroelastic response in the plate.
基金supported by the National Natural Science Foundation of China(Grant Nos.11472037,11272042&51506008)
文摘The shock wave standoff distances of near space hypersonic vehicles, which execute missions mainly at the altitude of 25 km to 55 km, are vital in aerothermodynamic analysis. The implicit finite volume schemes are derived from axisymmetric Navier-Stokes equations for chemical equilibrium flow, and programmed in FORTRAN. Taking a sphere cone for example, the effects of Much numbers （from 22 to 36） on the shock wave standoffdistance and the average density behind the shock are simulated at different altitudes from 25km to 55km. The numerical results illustrate that the turning point of the standoff distance is corresponding to that of the average density with the variation of Mach numbers. Based on the numerical results, we propose a formula for shock wave standoff distance, which is the function of the radius of the blunt body, the Mach number and the altitude in the atmosphere. Compared with previous correlations, the new formula can overcome the drawbacks of larger relative errors and complex calculations of the average density.
