This paper demonstrates the importance of three-dimensional(3-D)piezoelectric coupling in the electromechanical behavior of piezoelectric devices using three-dimensional finite element analyses based on weak and stron...This paper demonstrates the importance of three-dimensional(3-D)piezoelectric coupling in the electromechanical behavior of piezoelectric devices using three-dimensional finite element analyses based on weak and strong coupling models for a thin cantilevered piezoelectric bimorph actuator.It is found that there is a significant difference between the strong and weak coupling solutions given by coupling direct and inverse piezoelectric effects(i.e.,piezoelectric coupling effect).In addition,there is significant longitudinal bending caused by the constraint of the inverse piezoelectric effect in the width direction at the fixed end(i.e.,3-D effect).Hence,modeling of these effects or 3-D piezoelectric coupling modeling is an electromechanical basis for the piezoelectric devices,which contributes to the accurate prediction of their behavior.展开更多
Malignant ureteral obstruction may lead to renal function damage,renal colic,and infection.The impact of obstructive development on ureteral peristalsis was rarely studied,which requires further investigation.This stu...Malignant ureteral obstruction may lead to renal function damage,renal colic,and infection.The impact of obstructive development on ureteral peristalsis was rarely studied,which requires further investigation.This study used theoretical biomechanical methods to study the motion characteristics of the ureteral wall and obtained the radial motion equation of the ureteral wall.The motion equation was solved by 4-5th order Runge Kutta method.Analyze the motion equation of the ureteral wall,derive the expression for malignant obstructive ureteral pressure,as well as the analytical expressions for radial displacement and circumferential stress of the ureteral wall.By analyzing the radial motion equation of the ureter,it can be found that peristalsis is influenced by the pressure difference between inside and outside.The analytical solutions for radial displacement and stress contained exponential terms.Under the condition of 50%obstruction,the displacement and stress of the ureter were reduced by 90.53%and 81.10%,respectively.This study established the radial motion equation of the ureter and provided analytical solutions for the radial displacement and stress of the obstructed ureter.Based on the radial motion equation of the ureter,the radial motion characteristics of the ureteral wall were explored,including peristalsis and disappearance of peristalsis.This study provided a quantitative relationship between ureteral obstruction and peristalsis.As the degree of obstruction increased,ureteral peristalsis gradually weakened or even disappeared.展开更多
We report a theoretical work on the properties of modulational instability and bright type nonlinear localized modes in one-dimensional easy-axis weak ferromagnetic spin lattices involving next-nearest-neighbor coupli...We report a theoretical work on the properties of modulational instability and bright type nonlinear localized modes in one-dimensional easy-axis weak ferromagnetic spin lattices involving next-nearest-neighbor couplings.With a linear stability analysis, we calculate the growth rates of the modulational instability, and plot the instability regions.When the strength of the next-nearest-neighbor coupling is large enough, two new asymmetric modulational instability regions appear near the boundary of the first Brillouin zone.Furthermore, analytical forms of the bright nonlinear localized modes are constructed by means of a quasi-discreteness approach.The influence of the next-nearest-neighbor coupling on the Brillouin zone center mode and boundary mode are discussed.In particular, we discover a reversal phenomenon of the propagation direction of the Brillouin zone boundary mode.展开更多
Considering the maximum elastic limitation of the used material with newly advanced technology,the study focuses on optimization of a mortar barrel structure by thinning the wall to reduce the weight.Firstly,static an...Considering the maximum elastic limitation of the used material with newly advanced technology,the study focuses on optimization of a mortar barrel structure by thinning the wall to reduce the weight.Firstly,static analysis of barrel structure parameters is done based on finite element analysis（FEA）method and 3Dsolid model of the barrel is established based on Unigraphics NX（UG）.Secondly,the 3Dsolid model is simplified and transplanted to ANSYS for barrel wall pressure calculation.Thus,the change curves of the stress exerted on the barrel wall at different locations perpendicular to the axial direction with wall thinning are drawn.By analyzing all possible optimization schemes,the optimal design that enables the barrel to have higher bearing capacity is got.The optimized barrel structure is verified by means of fluid-solid coupling dynamic response analysis.The results show that the static analysis results are closer to real stress conditions than dynamic analysis results.Finally,the barrel weight is reduced by 13%after simulation optimization and the light weight design of the barrel is effective and reliable.展开更多
In this work,a bidirectional fluid-structure coupling finite element analysis model of the abdominal aorta was established,with the various vascular elastic modulus as the main parameters for atherosclerosis,taking in...In this work,a bidirectional fluid-structure coupling finite element analysis model of the abdominal aorta was established,with the various vascular elastic modulus as the main parameters for atherosclerosis,taking into consideration blood's dynamic viscosity and compressibility.Pressure and velocity pulse-wave propagation were investigated through the application of a full-coupling analysis algorithm.The effect of atherosclerosis degree on the propagation characteristics of pulse waves in the bifurcated abdominal aorta was quantitatively analyzed.Arterial bifurcation can cause substantial attenuation on the peak of pressure pulse waveform and an increase in wave velocity during the cardiac cycle.The elastic modulus and bifurcation properties of the arterial wall directly affected the peak value and wave propagation velocity of the pressure pulse wave.The preliminary results of this work will be crucial in guiding the evolution of the pressure pulse wave and the initial diagnosis of atherosclerotic disease through the waveform.展开更多
The finite element analysis(FEA) technology by hydraulic-mechanical-chemical-damage(HMCD) coupling is proposed in this paper for inclined wellbore stability analysis of water-sensitive and laminated rock, developed ba...The finite element analysis(FEA) technology by hydraulic-mechanical-chemical-damage(HMCD) coupling is proposed in this paper for inclined wellbore stability analysis of water-sensitive and laminated rock, developed basing on the recently established FEA technology for transversely isotropic rock with hydraulic-mechanical-damage(HMD) coupling. The chemical activity of the drilling fluid is considered as phenomenological hydration behavior, the moisture content and parameters of rock considering hydration could be determined with time. The finite element(FE) solutions of numerical wellbore model considering the chemical activity of drilling fluid, damage tensor calculation and weak plane strength criterion for transversely isotropic rock are developed for researching the wellbore failure characteristics and computing the time-dependent collapse and fracture pressure of laminated rock as shale reservoirs. A three-dimensional FE model and elastic solid deformation and seepage flow coupled equations are developed, and the damage tensor calculation technology for transversely isotropic rock are realized by introducing effect of the hydration and the stress state under the current load. The proposed method utilizing weak plane strength criterion fully reflects the strength parameters in rock matrix and weak plane. To the end, an effective and reliable numerically three-step FEA strategy is well established for wellbore stability analysis. Numerical examples are given to show that the proposed method can establish efficient and applicable FE model and be suitable for analyzing the timedependsolutions of pore pressure and stresses, and the evolution region considering the hydration surrounding wellbore,furthermore to compute the collapse cycling time and the safe mud weight for collapse and fracture pressure of transversely isotropic rock.展开更多
To quantitatively reveal how rock blocks falling into water affect the impulse waves,the influence of a rigid block on induced first wave and second wave is systematically investigated.The block characteristics includ...To quantitatively reveal how rock blocks falling into water affect the impulse waves,the influence of a rigid block on induced first wave and second wave is systematically investigated.The block characteristics include the initial velocity,density,volume,and incident angle,and the investigated wave behavior characteristics include the maximum kinetic energy of the water,the transformation ratio of the kinetic energy from the block to the waves,the duration of the waves,the maximum movement speed,and the maximum height and width of the waves.The coupled Eulerian-Lagrangian method(CEL)is introduced to establish the numerical models of the fluid-solid coupling,and a laboratory test of a rigid wedge sliding into water demonstrates that it can reasonably describe the dynamic behavior of a landslide-induced wave.A typical process of a block entering water and its energy variation are described and analyzed in detail.Further,the relationship between each characteristic parameter of the block and the waves is quantitatively investigated and fitted.The simulation results show that energy exchange between the block and the water is very rapid after the block collides with the water.The maximum kinetic energy,maximum velocity,duration,and side dimension of the waves mainly increase non-linearly with the above characteristic parameters of the block.The transformation ratio of the kinetic energy from the block to the water,the first wave,and the second wave are usually below 60%,45%,and 30%,respectively.The velocity of the block first decreases and then maintains a constant speed after entering the water.The displacement of the block increases linearly with the initial velocity and density of the block and exponentially increases with the block volume at different times.With the increase in the incident angle of the block,the kinetic energy and scale of the second wave increase correspondingly.展开更多
Combining theoretical and experimental modal analyses on self-excited vibration induced by dry friction between two elastic structures, we can explain the high-order sell-excited vibration phenomenon in which water dr...Combining theoretical and experimental modal analyses on self-excited vibration induced by dry friction between two elastic structures, we can explain the high-order sell-excited vibration phenomenon in which water droplets spurt from fourteen or twelve areas of the Chinese culture relic dragon washbasin when it is rubbed with hands, and clarify the mechanism of the singular high-order self-excited vibration. The experimental modes and the practical measured results are presented for a special dragon washbasin. The theoretical results agree well with the experimental ones.展开更多
基金supported by the Japan Society for the Promotion of Science under KAKENHI Grant Nos.19F19379 and 20H04199。
文摘This paper demonstrates the importance of three-dimensional(3-D)piezoelectric coupling in the electromechanical behavior of piezoelectric devices using three-dimensional finite element analyses based on weak and strong coupling models for a thin cantilevered piezoelectric bimorph actuator.It is found that there is a significant difference between the strong and weak coupling solutions given by coupling direct and inverse piezoelectric effects(i.e.,piezoelectric coupling effect).In addition,there is significant longitudinal bending caused by the constraint of the inverse piezoelectric effect in the width direction at the fixed end(i.e.,3-D effect).Hence,modeling of these effects or 3-D piezoelectric coupling modeling is an electromechanical basis for the piezoelectric devices,which contributes to the accurate prediction of their behavior.
基金supported by the National Natural Science Foundation of China(Grant Nos.12172034,U20A20390,and 11827803)Beijing Municipal Natural Science Foundation(Grant No.7212205)+1 种基金the 111 project(Grant No.B13003)the Fundamental Research Funds for the Central Universities.
文摘Malignant ureteral obstruction may lead to renal function damage,renal colic,and infection.The impact of obstructive development on ureteral peristalsis was rarely studied,which requires further investigation.This study used theoretical biomechanical methods to study the motion characteristics of the ureteral wall and obtained the radial motion equation of the ureteral wall.The motion equation was solved by 4-5th order Runge Kutta method.Analyze the motion equation of the ureteral wall,derive the expression for malignant obstructive ureteral pressure,as well as the analytical expressions for radial displacement and circumferential stress of the ureteral wall.By analyzing the radial motion equation of the ureter,it can be found that peristalsis is influenced by the pressure difference between inside and outside.The analytical solutions for radial displacement and stress contained exponential terms.Under the condition of 50%obstruction,the displacement and stress of the ureter were reduced by 90.53%and 81.10%,respectively.This study established the radial motion equation of the ureter and provided analytical solutions for the radial displacement and stress of the obstructed ureter.Based on the radial motion equation of the ureter,the radial motion characteristics of the ureteral wall were explored,including peristalsis and disappearance of peristalsis.This study provided a quantitative relationship between ureteral obstruction and peristalsis.As the degree of obstruction increased,ureteral peristalsis gradually weakened or even disappeared.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11604121 and 11875126)the Natural Science Fund Project of Hunan Province,China(Grant No.2017JJ3255)+1 种基金the National College Students’ Innovation Entrepreneurship Training Program,China(Grant No.201810531014)the Scientific Research Fund of Hunan Provincial Education Department,China(Grant No.17B212)
文摘We report a theoretical work on the properties of modulational instability and bright type nonlinear localized modes in one-dimensional easy-axis weak ferromagnetic spin lattices involving next-nearest-neighbor couplings.With a linear stability analysis, we calculate the growth rates of the modulational instability, and plot the instability regions.When the strength of the next-nearest-neighbor coupling is large enough, two new asymmetric modulational instability regions appear near the boundary of the first Brillouin zone.Furthermore, analytical forms of the bright nonlinear localized modes are constructed by means of a quasi-discreteness approach.The influence of the next-nearest-neighbor coupling on the Brillouin zone center mode and boundary mode are discussed.In particular, we discover a reversal phenomenon of the propagation direction of the Brillouin zone boundary mode.
文摘Considering the maximum elastic limitation of the used material with newly advanced technology,the study focuses on optimization of a mortar barrel structure by thinning the wall to reduce the weight.Firstly,static analysis of barrel structure parameters is done based on finite element analysis（FEA）method and 3Dsolid model of the barrel is established based on Unigraphics NX（UG）.Secondly,the 3Dsolid model is simplified and transplanted to ANSYS for barrel wall pressure calculation.Thus,the change curves of the stress exerted on the barrel wall at different locations perpendicular to the axial direction with wall thinning are drawn.By analyzing all possible optimization schemes,the optimal design that enables the barrel to have higher bearing capacity is got.The optimized barrel structure is verified by means of fluid-solid coupling dynamic response analysis.The results show that the static analysis results are closer to real stress conditions than dynamic analysis results.Finally,the barrel weight is reduced by 13%after simulation optimization and the light weight design of the barrel is effective and reliable.
基金supported by the National Natural Science Foundation of China(Grant No.11872218)Zhejiang Provincial Natural Science Foundation Key Projects(Grant No.LZ23A020001)+2 种基金the National Natural Science Foundation of China Regional Innovation Key Project(Grant No.U21A20502)Zhejiang Province Traditional Chinese Medicine Science and Technology Foundation(Grant No.2022ZB317)the first batch of Medical and Health Brand Discipline Foundation in Ningbo(Grant No.PPXK2018-07)。
文摘In this work,a bidirectional fluid-structure coupling finite element analysis model of the abdominal aorta was established,with the various vascular elastic modulus as the main parameters for atherosclerosis,taking into consideration blood's dynamic viscosity and compressibility.Pressure and velocity pulse-wave propagation were investigated through the application of a full-coupling analysis algorithm.The effect of atherosclerosis degree on the propagation characteristics of pulse waves in the bifurcated abdominal aorta was quantitatively analyzed.Arterial bifurcation can cause substantial attenuation on the peak of pressure pulse waveform and an increase in wave velocity during the cardiac cycle.The elastic modulus and bifurcation properties of the arterial wall directly affected the peak value and wave propagation velocity of the pressure pulse wave.The preliminary results of this work will be crucial in guiding the evolution of the pressure pulse wave and the initial diagnosis of atherosclerotic disease through the waveform.
基金supported by the National Natural Science Foundation of China(Grant Nos.11372157,11302115&51608301)the Doctoral Fund of Ministry of Education of China(Grant No.20120002110075)+1 种基金the Foundation for the Author of National Excellent Doctoral Dissertation of China(Grant No.201326)the China Postdoctoral Science Foundation(Grant No.2015M571030)
文摘The finite element analysis(FEA) technology by hydraulic-mechanical-chemical-damage(HMCD) coupling is proposed in this paper for inclined wellbore stability analysis of water-sensitive and laminated rock, developed basing on the recently established FEA technology for transversely isotropic rock with hydraulic-mechanical-damage(HMD) coupling. The chemical activity of the drilling fluid is considered as phenomenological hydration behavior, the moisture content and parameters of rock considering hydration could be determined with time. The finite element(FE) solutions of numerical wellbore model considering the chemical activity of drilling fluid, damage tensor calculation and weak plane strength criterion for transversely isotropic rock are developed for researching the wellbore failure characteristics and computing the time-dependent collapse and fracture pressure of laminated rock as shale reservoirs. A three-dimensional FE model and elastic solid deformation and seepage flow coupled equations are developed, and the damage tensor calculation technology for transversely isotropic rock are realized by introducing effect of the hydration and the stress state under the current load. The proposed method utilizing weak plane strength criterion fully reflects the strength parameters in rock matrix and weak plane. To the end, an effective and reliable numerically three-step FEA strategy is well established for wellbore stability analysis. Numerical examples are given to show that the proposed method can establish efficient and applicable FE model and be suitable for analyzing the timedependsolutions of pore pressure and stresses, and the evolution region considering the hydration surrounding wellbore,furthermore to compute the collapse cycling time and the safe mud weight for collapse and fracture pressure of transversely isotropic rock.
基金funded by the Second Tibetan Plateau Scientific Expedition and Research Program (STEP) (Grant No. 2021QZKK0202)the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDA20030301)+1 种基金the National Natural Science Foundation (Grant No. 41790432 and U22A20603)the fellowship of China Postdoctoral Science Foundation (Grant No. 2020M683369)
文摘To quantitatively reveal how rock blocks falling into water affect the impulse waves,the influence of a rigid block on induced first wave and second wave is systematically investigated.The block characteristics include the initial velocity,density,volume,and incident angle,and the investigated wave behavior characteristics include the maximum kinetic energy of the water,the transformation ratio of the kinetic energy from the block to the waves,the duration of the waves,the maximum movement speed,and the maximum height and width of the waves.The coupled Eulerian-Lagrangian method(CEL)is introduced to establish the numerical models of the fluid-solid coupling,and a laboratory test of a rigid wedge sliding into water demonstrates that it can reasonably describe the dynamic behavior of a landslide-induced wave.A typical process of a block entering water and its energy variation are described and analyzed in detail.Further,the relationship between each characteristic parameter of the block and the waves is quantitatively investigated and fitted.The simulation results show that energy exchange between the block and the water is very rapid after the block collides with the water.The maximum kinetic energy,maximum velocity,duration,and side dimension of the waves mainly increase non-linearly with the above characteristic parameters of the block.The transformation ratio of the kinetic energy from the block to the water,the first wave,and the second wave are usually below 60%,45%,and 30%,respectively.The velocity of the block first decreases and then maintains a constant speed after entering the water.The displacement of the block increases linearly with the initial velocity and density of the block and exponentially increases with the block volume at different times.With the increase in the incident angle of the block,the kinetic energy and scale of the second wave increase correspondingly.
基金The project supported by the National Natural Science Foundation of China (19872003)
文摘Combining theoretical and experimental modal analyses on self-excited vibration induced by dry friction between two elastic structures, we can explain the high-order sell-excited vibration phenomenon in which water droplets spurt from fourteen or twelve areas of the Chinese culture relic dragon washbasin when it is rubbed with hands, and clarify the mechanism of the singular high-order self-excited vibration. The experimental modes and the practical measured results are presented for a special dragon washbasin. The theoretical results agree well with the experimental ones.
