Advanced hole-making process is of great importance to enhance the fatigue performance of Al-Li alloy part in aviation industry.Ultrasonic peening drilling(UPD),in which an ultrasonic transversal vibration is applied ...Advanced hole-making process is of great importance to enhance the fatigue performance of Al-Li alloy part in aviation industry.Ultrasonic peening drilling(UPD),in which an ultrasonic transversal vibration is applied to the cutting tools,is a recently proposed hole-making method that integrates precision-machining and surface strengthening by single-shot operation.In the study,kinematics,material removal mechanism and strengthening mechanism for UPD of Al-Li alloy by helical fluted reamers are analyzed.The effect of transversal vibration on the cutting performance and surface integrity is studied through comparative experiments between UPD and conventional drilling(CD)of Al-Li alloy holes.The experimental results show that UPD exhibits superior cutting performance with a maximum reduction of 52.6%in thrust force and 52.3%in torque,respectively,compared to CD.Moreover,narrower dimensional tolerance is obtained in UPD due to the reduced transversal force and improved machining stability.Additionally,deeper plastic deformation,higher surface microhardness and residual compressive stress of machined holes are obtained by UPD.The electron back-scattered diffraction(EBSD)analysis confirms that deeper machined affect area and grain refinement are realized in UPD.Therefore,the results indicate that UPD is a feasible method for achieving high-precision and strengthened holes for Al-Li alloy.展开更多
In this paper,we prove a transversal V-Laplacian comparison theorem under a transversal Bakry-Emery Ricci condition.We establish a Schwarz type lemma for transversally V-harmonic maps of bounded generalized transversa...In this paper,we prove a transversal V-Laplacian comparison theorem under a transversal Bakry-Emery Ricci condition.We establish a Schwarz type lemma for transversally V-harmonic maps of bounded generalized transversal dilatation between Riemannian foliated manifolds by using this comparison theorem,including for the case of V=▽^(H)h.展开更多
This paper presents a new approach to synthesize admittance function polynomials and coupling matrices for coupled resonator filters. The N + 2 transversal network method is applied to study a coupled resonator f...This paper presents a new approach to synthesize admittance function polynomials and coupling matrices for coupled resonator filters. The N + 2 transversal network method is applied to study a coupled resonator filter. This method allowed us to determine the polynomials of the reflection and transmission coefficients. A study is made for a 4 poles filter with 2 transmission zeros between the N + 2 transversal network method and the one found in the literature. A MATLAB code was designed for the numerical simulation of these coefficients for the 6, 8, and 10 pole filter with 4 transmission zeros.展开更多
基金Supported by National Natural Science Foundation of China(Nos.52375399,91960203 and 51975035)Chinese Aeronautical Establishment Aeronautical Science Foundation(No.2022Z045051001).
文摘Advanced hole-making process is of great importance to enhance the fatigue performance of Al-Li alloy part in aviation industry.Ultrasonic peening drilling(UPD),in which an ultrasonic transversal vibration is applied to the cutting tools,is a recently proposed hole-making method that integrates precision-machining and surface strengthening by single-shot operation.In the study,kinematics,material removal mechanism and strengthening mechanism for UPD of Al-Li alloy by helical fluted reamers are analyzed.The effect of transversal vibration on the cutting performance and surface integrity is studied through comparative experiments between UPD and conventional drilling(CD)of Al-Li alloy holes.The experimental results show that UPD exhibits superior cutting performance with a maximum reduction of 52.6%in thrust force and 52.3%in torque,respectively,compared to CD.Moreover,narrower dimensional tolerance is obtained in UPD due to the reduced transversal force and improved machining stability.Additionally,deeper plastic deformation,higher surface microhardness and residual compressive stress of machined holes are obtained by UPD.The electron back-scattered diffraction(EBSD)analysis confirms that deeper machined affect area and grain refinement are realized in UPD.Therefore,the results indicate that UPD is a feasible method for achieving high-precision and strengthened holes for Al-Li alloy.
文摘In this paper,we prove a transversal V-Laplacian comparison theorem under a transversal Bakry-Emery Ricci condition.We establish a Schwarz type lemma for transversally V-harmonic maps of bounded generalized transversal dilatation between Riemannian foliated manifolds by using this comparison theorem,including for the case of V=▽^(H)h.
文摘This paper presents a new approach to synthesize admittance function polynomials and coupling matrices for coupled resonator filters. The N + 2 transversal network method is applied to study a coupled resonator filter. This method allowed us to determine the polynomials of the reflection and transmission coefficients. A study is made for a 4 poles filter with 2 transmission zeros between the N + 2 transversal network method and the one found in the literature. A MATLAB code was designed for the numerical simulation of these coefficients for the 6, 8, and 10 pole filter with 4 transmission zeros.
