Functionally graded materials(FGMs)are a novel class of composite materials that have attracted significant attention in the field of engineering due to their unique mechanical properties.This study aims to explore th...Functionally graded materials(FGMs)are a novel class of composite materials that have attracted significant attention in the field of engineering due to their unique mechanical properties.This study aims to explore the dynamic behaviors of an FGM stepped beam with different boundary conditions based on an efficient solving method.Under the assumptions of the Euler-Bernoulli beam theory,the governing differential equations of an individual FGM beam are derived with Hamilton’s principle and decoupled via the separation-of-variable approach.Then,the free and forced vibrations of the FGM stepped beam are solved with the transfer matrix method(TMM).Two models,i.e.,a three-level FGM stepped beam and a five-level FGM stepped beam,are considered,and their natural frequencies and mode shapes are presented.To demonstrate the validity of the method in this paper,the simulation results by ABAQUS are also given.On this basis,the detailed parametric analyses on the frequencies and dynamic responses of the three-level FGM stepped beam are carried out.The results show the accuracy and efficiency of the TMM.展开更多
Esophageal disease is a common disorder of the digestive system that can severely affect the quality of life andprognosis of patients. Esophageal stenting is an effective treatment that has been widely used in clinica...Esophageal disease is a common disorder of the digestive system that can severely affect the quality of life andprognosis of patients. Esophageal stenting is an effective treatment that has been widely used in clinical practice.However, esophageal stents of different types and parameters have varying adaptability and effectiveness forpatients, and they need to be individually selected according to the patient’s specific situation. The purposeof this study was to provide a reference for clinical doctors to choose suitable esophageal stents. We used 3Dprinting technology to fabricate esophageal stents with different ratios of thermoplastic polyurethane (TPU)/(Poly-ε-caprolactone) PCL polymer, and established an artificial neural network model that could predict the radial forceof esophageal stents based on the content of TPU, PCL and print parameter. We selected three optimal ratios formechanical performance tests and evaluated the biomechanical effects of different ratios of stents on esophagealimplantation, swallowing, and stent migration processes through finite element numerical simulation and in vitrosimulation tests. The results showed that different ratios of polymer stents had different mechanical properties,affecting the effectiveness of stent expansion treatment and the possibility of postoperative complications of stentimplantation.展开更多
In previous research on the nonlinear dynamics of cable-stayed bridges,boundary conditions were not properly modeled in the modeling.In order to obtain the nonlinear dynamics of cable-stayed bridges more accurately,a ...In previous research on the nonlinear dynamics of cable-stayed bridges,boundary conditions were not properly modeled in the modeling.In order to obtain the nonlinear dynamics of cable-stayed bridges more accurately,a double-cable-stayed shallow-arch model with elastic supports at both ends and the initial configuration of bridge deck included in the modeling is developed in this study.The in-plane eigenvalue problems of the model are solved by dividing the shallow arch(SA)into three partitions according to the number of cables and the piecewise functions are taken as trial functions of the SA.Then,the in-plane one-toone-to-one internal resonance among the global mode and the local modes(two cables’modes)is investigated when external primary resonance occurs.The ordinary differential equations(ODEs)are obtained by Galerkin’s method and solved by the method of multiple time scales.The stable equilibrium solutions of modulation equations are obtained by using the NewtonRaphson method.In addition,the frequency-/force-response curves under different vertical stiffness are provided to study the nonlinear dynamic behaviors of the elastically supported model.To validate the theoretical analyses,the Runge-Kutta method is applied to obtain the numerical solutions.Finally,some interesting conclusions are drawn.展开更多
The present study aims to investigate the dynamic behaviors and energy transfer between components of a cable stayed beam structure subjected to a concentrated load,in which the primary resonance of the beam and one-t...The present study aims to investigate the dynamic behaviors and energy transfer between components of a cable stayed beam structure subjected to a concentrated load,in which the primary resonance of the beam and one-to-two internal resonance between modes of the beam and the cable occur.Galerkin discretization and multiple time scales method are applied to derive the modulation equations of the system governing the amplitude and phase.Two sags of span ratios are defined to modulate the internal resonance.Frequency response,amplitude response,phase diagram,Poincare map,and time history curves are calculated and used to investigate the modal resonance dynamics.The results demonstrate that the beam and the cable have two resonant peaks in frequency responses,where the beam always shows hardening spring property and the cable may present hardening and softening spring properties affected by sag to span ratio.The system is prone to complex dynamic behavior with the small amplitude excitation in the primary resonance region.展开更多
基金the National Natural Science Foundation of China(Nos.12302007,12372006,and 12202109)the Specific Research Project of Guangxi for Research Bases and Talents(No.AD23026051)。
文摘Functionally graded materials(FGMs)are a novel class of composite materials that have attracted significant attention in the field of engineering due to their unique mechanical properties.This study aims to explore the dynamic behaviors of an FGM stepped beam with different boundary conditions based on an efficient solving method.Under the assumptions of the Euler-Bernoulli beam theory,the governing differential equations of an individual FGM beam are derived with Hamilton’s principle and decoupled via the separation-of-variable approach.Then,the free and forced vibrations of the FGM stepped beam are solved with the transfer matrix method(TMM).Two models,i.e.,a three-level FGM stepped beam and a five-level FGM stepped beam,are considered,and their natural frequencies and mode shapes are presented.To demonstrate the validity of the method in this paper,the simulation results by ABAQUS are also given.On this basis,the detailed parametric analyses on the frequencies and dynamic responses of the three-level FGM stepped beam are carried out.The results show the accuracy and efficiency of the TMM.
基金Nanning Technology and Innovation Special Program(20204122)and Research Grant for 100 Talents of Guangxi Plan.
文摘Esophageal disease is a common disorder of the digestive system that can severely affect the quality of life andprognosis of patients. Esophageal stenting is an effective treatment that has been widely used in clinical practice.However, esophageal stents of different types and parameters have varying adaptability and effectiveness forpatients, and they need to be individually selected according to the patient’s specific situation. The purposeof this study was to provide a reference for clinical doctors to choose suitable esophageal stents. We used 3Dprinting technology to fabricate esophageal stents with different ratios of thermoplastic polyurethane (TPU)/(Poly-ε-caprolactone) PCL polymer, and established an artificial neural network model that could predict the radial forceof esophageal stents based on the content of TPU, PCL and print parameter. We selected three optimal ratios formechanical performance tests and evaluated the biomechanical effects of different ratios of stents on esophagealimplantation, swallowing, and stent migration processes through finite element numerical simulation and in vitrosimulation tests. The results showed that different ratios of polymer stents had different mechanical properties,affecting the effectiveness of stent expansion treatment and the possibility of postoperative complications of stentimplantation.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.11972151 and 11872176)。
文摘In previous research on the nonlinear dynamics of cable-stayed bridges,boundary conditions were not properly modeled in the modeling.In order to obtain the nonlinear dynamics of cable-stayed bridges more accurately,a double-cable-stayed shallow-arch model with elastic supports at both ends and the initial configuration of bridge deck included in the modeling is developed in this study.The in-plane eigenvalue problems of the model are solved by dividing the shallow arch(SA)into three partitions according to the number of cables and the piecewise functions are taken as trial functions of the SA.Then,the in-plane one-toone-to-one internal resonance among the global mode and the local modes(two cables’modes)is investigated when external primary resonance occurs.The ordinary differential equations(ODEs)are obtained by Galerkin’s method and solved by the method of multiple time scales.The stable equilibrium solutions of modulation equations are obtained by using the NewtonRaphson method.In addition,the frequency-/force-response curves under different vertical stiffness are provided to study the nonlinear dynamic behaviors of the elastically supported model.To validate the theoretical analyses,the Runge-Kutta method is applied to obtain the numerical solutions.Finally,some interesting conclusions are drawn.
基金supported by the National Natural Science Foundation of China(Grant Nos.11972151 and 11872176).
文摘The present study aims to investigate the dynamic behaviors and energy transfer between components of a cable stayed beam structure subjected to a concentrated load,in which the primary resonance of the beam and one-to-two internal resonance between modes of the beam and the cable occur.Galerkin discretization and multiple time scales method are applied to derive the modulation equations of the system governing the amplitude and phase.Two sags of span ratios are defined to modulate the internal resonance.Frequency response,amplitude response,phase diagram,Poincare map,and time history curves are calculated and used to investigate the modal resonance dynamics.The results demonstrate that the beam and the cable have two resonant peaks in frequency responses,where the beam always shows hardening spring property and the cable may present hardening and softening spring properties affected by sag to span ratio.The system is prone to complex dynamic behavior with the small amplitude excitation in the primary resonance region.
