The stable steady-state periodic responses of a belt-drive system with a one-way clutch are studied. For the first time, the dynamical system is investigated under dual excitations. The system is simultaneously excite...The stable steady-state periodic responses of a belt-drive system with a one-way clutch are studied. For the first time, the dynamical system is investigated under dual excitations. The system is simultaneously excited by the firing pulsations of the engine and the harmonic motion of the foundation. Nonlinear discrete-continuous equations are derived for coupling the transverse vibration of the belt spans and the rotations of the driving and driven pulleys and the accessory pulley. The nonlinear dynamics is studied under equal and multiple relations between the frequency of the fir- ing pulsations and the frequency of the foundation motion. Furthermore, translating belt spans are modeled as axially moving strings. A set of nonlinear piecewise ordinary differ- ential equations is achieved by using the Galerkin truncation. Under various relations between the excitation frequencies, the time histories of the dynamical system are numerically simulated based on the time discretization method. Further- more, the stable steady-state periodic response curves are calculated based on the frequency sweep. Moreover, the convergence of the Galerkin truncation is examined. Numer- ical results demonstrate that the one-way clutch reduces the resonance amplitude of the rotations of the driven pul- ley and the accessory pulley. On the other hand, numerical examples prove that the resonance areas of the belt spans are decreased by eliminating the torque-transmitting in the opposite direction. With the increasing amplitude of the foun- dation excitation, the damping effect of the one-way clutch will be reduced. Furthermore, as the amplitude of the firing pulsations of the engine increases, the jumping phenomena in steady-state response curves of the belt-drive system with or without a one-way clutch both occur.展开更多
The improved element-free Galerkin （IEFG） method of elasticity is used to solve the topology optimization problems. In this method, the improved moving least-squares approximation is used to form the shape function....The improved element-free Galerkin （IEFG） method of elasticity is used to solve the topology optimization problems. In this method, the improved moving least-squares approximation is used to form the shape function. In a topology opti- mization process, the entire structure volume is considered as the constraint. From the solid isotropic microstructures with penalization, we select relative node density as a design variable. Then we choose the minimization of compliance to be an objective function, and compute its sensitivity with the adjoint method. The IEFG method in this paper can overcome the disadvantages of the singular matrices that sometimes appear in conventional element-free Galerkin （EFG） method. The central processing unit （CPU） time of each example is given to show that the IEFG method is more efficient than the EFG method under the same precision, and the advantage that the IEFG method does not form singular matrices is also shown.展开更多
The Boussinesq approximation finds more and more frequent use in geologi- cal practice. In this paper, the asymptotic behavior of solution for fractional Boussinesq approximation is studied. After obtaining some a pri...The Boussinesq approximation finds more and more frequent use in geologi- cal practice. In this paper, the asymptotic behavior of solution for fractional Boussinesq approximation is studied. After obtaining some a priori estimates with the aid of eommu- tator estimate, we apply the Galerkin method to prove the existence of weak solution in the case of periodic domain. Meanwhile, the uniqueness is also obtained. Because the results obtained are independent of domain, the existence and uniqueness of the weak solution for Cauchy problem is also true. Finally, we use the Fourier splitting method to prove the decay of weak solution in three cases respectively.展开更多
B iolum inescence in aghg is a khd ofem erghg detection technology at cellular, m olecu lar and genetic level. The most popular b io lum m inescence in aghg model is diffusion approxin ation （DA）. However, because ...B iolum inescence in aghg is a khd ofem erghg detection technology at cellular, m olecu lar and genetic level. The most popular b io lum m inescence in aghg model is diffusion approxin ation （DA）. However, because of the ill-posedness of the D A -based hverse problem and the instability of reconstruction algorithm s, the location accuracy of the reconstucted sources is low. Radiative transfer equation （RTE）, which considers the direction of the photon m igration and the effect of absorption and scattering in tissues, can accurately express the transmission ofbiolum hescent photns through the tissues. In this paper, we studied the biolum hescence inaging based on the RTE. 2D sinuiations were performed, and quantitative evaluation was given by the absolute source position error, the relative source area error and the m h in um bound hg box. The resu Its of the experin ent showed that the in aging quality based on R TE was beer than thatone based on D A.展开更多
基金project was supported by the State Key Program of the National Natural Science Foundation of China(Grant 11232009)the National Natural Science Foundation of China(Grants 11372171,11422214)
文摘The stable steady-state periodic responses of a belt-drive system with a one-way clutch are studied. For the first time, the dynamical system is investigated under dual excitations. The system is simultaneously excited by the firing pulsations of the engine and the harmonic motion of the foundation. Nonlinear discrete-continuous equations are derived for coupling the transverse vibration of the belt spans and the rotations of the driving and driven pulleys and the accessory pulley. The nonlinear dynamics is studied under equal and multiple relations between the frequency of the fir- ing pulsations and the frequency of the foundation motion. Furthermore, translating belt spans are modeled as axially moving strings. A set of nonlinear piecewise ordinary differ- ential equations is achieved by using the Galerkin truncation. Under various relations between the excitation frequencies, the time histories of the dynamical system are numerically simulated based on the time discretization method. Further- more, the stable steady-state periodic response curves are calculated based on the frequency sweep. Moreover, the convergence of the Galerkin truncation is examined. Numer- ical results demonstrate that the one-way clutch reduces the resonance amplitude of the rotations of the driven pul- ley and the accessory pulley. On the other hand, numerical examples prove that the resonance areas of the belt spans are decreased by eliminating the torque-transmitting in the opposite direction. With the increasing amplitude of the foun- dation excitation, the damping effect of the one-way clutch will be reduced. Furthermore, as the amplitude of the firing pulsations of the engine increases, the jumping phenomena in steady-state response curves of the belt-drive system with or without a one-way clutch both occur.
基金supported by the National Natural Science Foundation of China(Grant Nos.11571223 and U1433104)
文摘The improved element-free Galerkin （IEFG） method of elasticity is used to solve the topology optimization problems. In this method, the improved moving least-squares approximation is used to form the shape function. In a topology opti- mization process, the entire structure volume is considered as the constraint. From the solid isotropic microstructures with penalization, we select relative node density as a design variable. Then we choose the minimization of compliance to be an objective function, and compute its sensitivity with the adjoint method. The IEFG method in this paper can overcome the disadvantages of the singular matrices that sometimes appear in conventional element-free Galerkin （EFG） method. The central processing unit （CPU） time of each example is given to show that the IEFG method is more efficient than the EFG method under the same precision, and the advantage that the IEFG method does not form singular matrices is also shown.
基金Sponsored by the Fundamental Research Funds for the Central Universities(2010QS04)the National Science Foundation of China(11201475,11126160,11201185)Zhejiang Provincial Natural Science Foundation of China under Grant(LQ12A01013)
文摘The Boussinesq approximation finds more and more frequent use in geologi- cal practice. In this paper, the asymptotic behavior of solution for fractional Boussinesq approximation is studied. After obtaining some a priori estimates with the aid of eommu- tator estimate, we apply the Galerkin method to prove the existence of weak solution in the case of periodic domain. Meanwhile, the uniqueness is also obtained. Because the results obtained are independent of domain, the existence and uniqueness of the weak solution for Cauchy problem is also true. Finally, we use the Fourier splitting method to prove the decay of weak solution in three cases respectively.
基金The Funding of Jiangsu Innovation Program for Graduate Educationgrant number:SJLX15_0115+1 种基金the Fundamental Research Funds for the Central Universities of Chinagrant number NZ2014101
文摘B iolum inescence in aghg is a khd ofem erghg detection technology at cellular, m olecu lar and genetic level. The most popular b io lum m inescence in aghg model is diffusion approxin ation （DA）. However, because of the ill-posedness of the D A -based hverse problem and the instability of reconstruction algorithm s, the location accuracy of the reconstucted sources is low. Radiative transfer equation （RTE）, which considers the direction of the photon m igration and the effect of absorption and scattering in tissues, can accurately express the transmission ofbiolum hescent photns through the tissues. In this paper, we studied the biolum hescence inaging based on the RTE. 2D sinuiations were performed, and quantitative evaluation was given by the absolute source position error, the relative source area error and the m h in um bound hg box. The resu Its of the experin ent showed that the in aging quality based on R TE was beer than thatone based on D A.
基金Supported by the National Natural Science Foundation of China(11761054,11261035,11571002)the Program for Young Talents of Science and Technology in Universities of Inner Mongolia Autonomous Region(NJYT-15-A07)+3 种基金the Natural Science Foundation of Inner Mongolia Autonomous Region,China(2015MS0108,2012MS0102)the Science Research Foundation of Institute of Higher Education of Inner Mongolia Autonomous Region,China(NJZZ12198,NJZZ16234,NJZZ16235)Science and Technology Development Foundation of CAEP(2015B0101021)Defense Industrial Technology Development Program(B1520133015)
