The grillage adaptive beam string structure(GABSS)is a new type of smart structure that can self-adjust its deformation and internal forces through a group of active struts(actuators)in response to changes in environm...The grillage adaptive beam string structure(GABSS)is a new type of smart structure that can self-adjust its deformation and internal forces through a group of active struts(actuators)in response to changes in environmental conditions.In this paper,an internal force control method based on a gradient–genetic algorithm(GGA)is proposed for the static control of a tensioned structure(especially the GABSS).Specifically,an optimization model of the GABSS is established in which the adjustment values of the actuators are set as the control variables,and the internal force of the beam is set as the objective function.The improved algorithm has the advantage of the global optimization ability of the genetic algorithm and the local search ability of the gradient algorithm.Two examples are provided to illustrate the application of the GGA method.The results show that the proposed method is practical for solving the internal force control problem of the GABSS.展开更多
In this paper,the nonlinear dynamic behavior of a string-beam coupled system subjected to external,parametric and tuned excitations is presented.The governing equations of motion are obtained for the nonlinear transve...In this paper,the nonlinear dynamic behavior of a string-beam coupled system subjected to external,parametric and tuned excitations is presented.The governing equations of motion are obtained for the nonlinear transverse vibrations of the string-beam coupled system which are described by a set of ordinary differential equations with two degrees of freedom.The case of 1:1 internal resonance between the modes of the beam and string,and the primary and combined resonance for the beam is considered.The method of multiple scales is utilized to analyze the nonlinear responses of the string-beam coupled system and obtain approximate solutions up to and including the second-order approximations.All resonance cases are extracted and investigated.Stability of the system is studied using frequency response equations and the phase-plane method.Numerical solutions are carried out and the results are presented graphically and discussed.The effects of the different parameters on both response and stability of the system are investigated.The reported results are compared to the available published work.展开更多
An improved whole model of beam pumping system was built. In the detail, for surface transmission system(STS), a new mathematical model was established considering the influence of some factors on the STS's torsio...An improved whole model of beam pumping system was built. In the detail, for surface transmission system(STS), a new mathematical model was established considering the influence of some factors on the STS's torsional vibration, such as the time variation characteristic of equivalent stiffness of belt and equivalent rotational inertia of crank. For the sucker rod string(SRS), an improved mathematical model was built considering the influence of some parameters on the SRS's longitudinal vibration, such as the nonlinear friction of plunger, hydraulic loss of pump and clearance leakage. The dynamic response and system efficiency of whole system were analyzed. The results show that there is a jumping phenomenon in the amplitude frequency curve, and the system efficiency is sensitive to motor power, pump diameter, stroke number, ratio of gas and oil, and submergence depth. The simulation results have important significance for improving the efficiency of beam pumping system.展开更多
基金supported by the National Key R&D Program of China(No.2017YFC0806100)the National Natural Science Foundation of China(No.51578491)。
文摘The grillage adaptive beam string structure(GABSS)is a new type of smart structure that can self-adjust its deformation and internal forces through a group of active struts(actuators)in response to changes in environmental conditions.In this paper,an internal force control method based on a gradient–genetic algorithm(GGA)is proposed for the static control of a tensioned structure(especially the GABSS).Specifically,an optimization model of the GABSS is established in which the adjustment values of the actuators are set as the control variables,and the internal force of the beam is set as the objective function.The improved algorithm has the advantage of the global optimization ability of the genetic algorithm and the local search ability of the gradient algorithm.Two examples are provided to illustrate the application of the GGA method.The results show that the proposed method is practical for solving the internal force control problem of the GABSS.
文摘In this paper,the nonlinear dynamic behavior of a string-beam coupled system subjected to external,parametric and tuned excitations is presented.The governing equations of motion are obtained for the nonlinear transverse vibrations of the string-beam coupled system which are described by a set of ordinary differential equations with two degrees of freedom.The case of 1:1 internal resonance between the modes of the beam and string,and the primary and combined resonance for the beam is considered.The method of multiple scales is utilized to analyze the nonlinear responses of the string-beam coupled system and obtain approximate solutions up to and including the second-order approximations.All resonance cases are extracted and investigated.Stability of the system is studied using frequency response equations and the phase-plane method.Numerical solutions are carried out and the results are presented graphically and discussed.The effects of the different parameters on both response and stability of the system are investigated.The reported results are compared to the available published work.
基金Projects(50974108,51174175) supported by the National Natural Science Foundation of China
文摘An improved whole model of beam pumping system was built. In the detail, for surface transmission system(STS), a new mathematical model was established considering the influence of some factors on the STS's torsional vibration, such as the time variation characteristic of equivalent stiffness of belt and equivalent rotational inertia of crank. For the sucker rod string(SRS), an improved mathematical model was built considering the influence of some parameters on the SRS's longitudinal vibration, such as the nonlinear friction of plunger, hydraulic loss of pump and clearance leakage. The dynamic response and system efficiency of whole system were analyzed. The results show that there is a jumping phenomenon in the amplitude frequency curve, and the system efficiency is sensitive to motor power, pump diameter, stroke number, ratio of gas and oil, and submergence depth. The simulation results have important significance for improving the efficiency of beam pumping system.
