Removal of milling marks at the root fillet of titanium alloy blade is a tough work because of the interference between the polishing tool and the workpiece.A polishing method based on elastic magnetic tool was propos...Removal of milling marks at the root fillet of titanium alloy blade is a tough work because of the interference between the polishing tool and the workpiece.A polishing method based on elastic magnetic tool was proposed.The software ANSYS Maxwell was used to simulate the effect of different pole orientation arrangements on the magnetic field distribution.A comparison of polishing effect was made between elastic and inelastic magnetic pole carriers.The processing parameters of the elastic magnetic tool polishing for the blade root were optimized by orthogonal experiment(Taguchi)method.Results show that compared with the inelastic magnetic polishing tool,the elastic magnetic polishing tool with polyurethane as the pole carrier can effectively improve the surface quality of the polished workpiece.Under the optimal processing parameters(rotational speed=900 r/min,feeding rate=6 mm/min,machining gap=1.5 mm and abrasive size=10‒14μm),the original milling marks at the blade root are effectively removed and the average surface roughness Ra is dropped from 0.95μm to 0.12μm,which verifies the feasibility of the elastic magnetic polishing tool in the surface finishing of the titanium alloy blade root.展开更多
Based on the long-wavelength approximation,a set of parallel vertical fractures embedded in periodic thin interbeds can be regarded as an equivalent orthorhombic medium. Rock physics is the basis for constructing the ...Based on the long-wavelength approximation,a set of parallel vertical fractures embedded in periodic thin interbeds can be regarded as an equivalent orthorhombic medium. Rock physics is the basis for constructing the relationship between fracture parameters and seismic response. Seismic scattering is an effective way to inverse anisotropic parameters. In this study,we propose a reliable method for predicting the Thomsen's weak anisotropic parameters and fracture weaknesses in an orthorhombic fractured reservoir using azimuthal pre-stack seismic data. First, considering the influence of fluid substitution in mineral matrix, porosity, fractures and anisotropic rocks, we estimate the orthorhombic anisotropic stiffness coefficients by constructing an equivalent rock physics model for fractured rocks. Further, we predict the logging elastic parameters, Thomsen's weak parameters, and fracture weaknesses to provide the initial model constraints for the seismic inversion. Then, we derive the P-wave reflection coefficient equation for the inversion of Thomsen's weak anisotropic parameters and fracture weaknesses.Cauchy-sparse and smoothing-model constraint regularization taken into account in a Bayesian framework, we finally develop a method of amplitude variation with angles of incidence and azimuth(AVAZ) inversion for Thomsen's weak anisotropic parameters and fracture weaknesses, and the model parameters are estimated by using the nonlinear iteratively reweighted least squares(IRLS) strategy. Both synthetic and real examples show that the method can directly estimate the orthorhombic characteristic parameters from the azimuthally pre-stack seismic data, which provides a reliable seismic inversion method for predicting Thomsen's weak anisotropic parameters and fracture weaknesses.展开更多
基金Joint Funds of the National Natural Science Foundation of China(U20A20293)。
文摘Removal of milling marks at the root fillet of titanium alloy blade is a tough work because of the interference between the polishing tool and the workpiece.A polishing method based on elastic magnetic tool was proposed.The software ANSYS Maxwell was used to simulate the effect of different pole orientation arrangements on the magnetic field distribution.A comparison of polishing effect was made between elastic and inelastic magnetic pole carriers.The processing parameters of the elastic magnetic tool polishing for the blade root were optimized by orthogonal experiment(Taguchi)method.Results show that compared with the inelastic magnetic polishing tool,the elastic magnetic polishing tool with polyurethane as the pole carrier can effectively improve the surface quality of the polished workpiece.Under the optimal processing parameters(rotational speed=900 r/min,feeding rate=6 mm/min,machining gap=1.5 mm and abrasive size=10‒14μm),the original milling marks at the blade root are effectively removed and the average surface roughness Ra is dropped from 0.95μm to 0.12μm,which verifies the feasibility of the elastic magnetic polishing tool in the surface finishing of the titanium alloy blade root.
文摘Based on the long-wavelength approximation,a set of parallel vertical fractures embedded in periodic thin interbeds can be regarded as an equivalent orthorhombic medium. Rock physics is the basis for constructing the relationship between fracture parameters and seismic response. Seismic scattering is an effective way to inverse anisotropic parameters. In this study,we propose a reliable method for predicting the Thomsen's weak anisotropic parameters and fracture weaknesses in an orthorhombic fractured reservoir using azimuthal pre-stack seismic data. First, considering the influence of fluid substitution in mineral matrix, porosity, fractures and anisotropic rocks, we estimate the orthorhombic anisotropic stiffness coefficients by constructing an equivalent rock physics model for fractured rocks. Further, we predict the logging elastic parameters, Thomsen's weak parameters, and fracture weaknesses to provide the initial model constraints for the seismic inversion. Then, we derive the P-wave reflection coefficient equation for the inversion of Thomsen's weak anisotropic parameters and fracture weaknesses.Cauchy-sparse and smoothing-model constraint regularization taken into account in a Bayesian framework, we finally develop a method of amplitude variation with angles of incidence and azimuth(AVAZ) inversion for Thomsen's weak anisotropic parameters and fracture weaknesses, and the model parameters are estimated by using the nonlinear iteratively reweighted least squares(IRLS) strategy. Both synthetic and real examples show that the method can directly estimate the orthorhombic characteristic parameters from the azimuthally pre-stack seismic data, which provides a reliable seismic inversion method for predicting Thomsen's weak anisotropic parameters and fracture weaknesses.
