51 results about "Elastic wave velocity" patented technology

The present invention provides systems and methods to used a measured driving-point response of a nonlinear material to determined one or more elastic properties of the material. The present invention takes advantage of the full information represented by the transient component, the steady-state component, the anharmonic components, and the nonlinear response components of a measured driving-point response of a real nonlinear material, without limitation in the use of large-amplitude forces. The elastic properties are determined by forming and solving a time-domain system of linear equations representing a differential equation model of the driving-point motions of the material. Based on a single, short duration, large-amplitude driving point measurement, both linear and nonlinear properties can be determined; both large-amplitude and near-zero amplitude properties can be determined; and elastic-wave speed and elastic moduli and their variation with depth can be determined.

The invention provides an elastic migration seismic wave field construction method and an elastic migration seismic wave field construction device. The method includes computing a finite difference coefficient of extended compact staggered grids according to an elastic wave velocity stress equation; computing a finite difference operator matrix of the extended compact staggered grids; constructing forward direction extrapolation operator of a seismic source wave field, and a reverse-time extrapolation operator of a detection wave field; achieving forward direction extrapolation of a seismic wave field to obtain the seismic source wave field according to the forward direction extrapolation operator of the seismic source wave field, a preset medium model and a preset seismic source function; and achieving reverse-time extrapolation of the seismic wave field to obtain the detection wave field according to the reverse-time extrapolation operator of the detection wave field, a preset medium model and preset multi-component seismic data. Compared with an existing method for constructing an elastic deflection seismic wave field by utilization of a conventional finite difference method and a compact difference method, the number of difference base frame grid points is reduced under the condition of same difference orders, the construction precision of a complex medium wave field can be effectively improved, and therefore the imaging precision of reverse-time migration is improved.

The invention relates to a nondestructive testing method for the bearing capacity of a concrete bridge based on elastic modulus, and belongs to the technical field of engineering testing. The nondestructive testing method comprises the steps of: dividing a stress area into a compression area, a tensioning area, a shearing area and a neutral area without stress according to the type of the concrete bridge; carrying out impact elastic wave velocity testing on all the areas, knocking an excitation block and changing an excitation direction, so as to obtain first waves of an excitation elastic wave, namely a compression wave and a tensile wave, and deducing whether cracks exist in a testing area or not according to the velocity difference of the two waves; calculating the concrete tangent elastic modulus Ed; measuring the concrete elastic modulus Ec, and deducing the compressive strength of concrete; deducing the stress level and the stress state of the corresponding area according to the concrete tangent elastic modulus and the compressive strength of the concrete in all the areas; and deducing the bearing capacity of the bridge according to the stress level and the stress state of all the areas. By implementing the nondestructive testing method, safety guarantee data can be provided for the health evaluation of the bridge.