The nonlinear vibration of graphene platelets reinforced composite corrugated(GPRCC)rectangular plates with shallow trapezoidal corrugations is investigated.Since graphene platelets are prone to agglomeration,a multi-...The nonlinear vibration of graphene platelets reinforced composite corrugated(GPRCC)rectangular plates with shallow trapezoidal corrugations is investigated.Since graphene platelets are prone to agglomeration,a multi-layer distribution is adopted here to match the engineering requirements.Firstly,an equivalent composite plate model is obtained,and then nonlinear equations of motion are derived by the von Kármán nonlinear geometric relationship and Hamilton’s principle.Afterwards,the Galerkin method and harmonic balance method are used to obtain an approximate analytical solution.Results show that the unit cell half period,unit cell inclination angle,unit cell height,graphene platelet dispersion pattern and graphene platelet weight fraction and geometry play important roles in the nonlinear vibration of the GPRCC plates.展开更多
平直机翼和卫星太阳能帆板等结构通常简化为矩形悬臂板,在实际应用中,这些结构通常会面临复杂的弯曲和扭转耦合振动问题,尤其在共振情况下,可能导致结构损伤甚至失效.目前,针对这类结构的共振抑制研究大多集中于弯曲振动的控制,对于弯...平直机翼和卫星太阳能帆板等结构通常简化为矩形悬臂板,在实际应用中,这些结构通常会面临复杂的弯曲和扭转耦合振动问题,尤其在共振情况下,可能导致结构损伤甚至失效.目前,针对这类结构的共振抑制研究大多集中于弯曲振动的控制,对于弯扭耦合振动的研究相对较少.文章探索了分布式非线性能量汇(nonlinear energy sink,NES)对这类结构弯扭两种共振模式及多个共振模态耦合的抑振效果.首先,基于广义哈密顿原理和牛顿法,建立了含分布式NES胞元的矩形悬臂板弯扭耦合振动的动力学模型.然后,采用伽辽金截断法得到弯扭耦合振动离散方程,并使用谐波平衡法计算稳态响应,利用龙格库塔法进行验证.最后,通过对比不同NES胞元参数的控制效果,讨论了参数对悬臂板结构减振效果的影响规律.研究结果表明,相同NES质量下提高吸振器非线性刚度和恰当阻尼条件下,可以显著提高弯扭耦合振动控制效果.这些结果为矩形悬臂板类结构的弯扭耦合振动抑制提供了新的思路和理论依据,也为该类结构的被动控制策略的优化设计提供了有价值的参考.展开更多
非线性能量汇(nonlinear energy sink, NES)在被动控制中有着广阔的应用前景,然而这一领域的研究主要集中在单向吸振器上,这限制了其在实际应用中对多向振动的适用性。设计了一种多向NES,利用相互正交的两组钢丝绳结构,实现了单振子空...非线性能量汇(nonlinear energy sink, NES)在被动控制中有着广阔的应用前景,然而这一领域的研究主要集中在单向吸振器上,这限制了其在实际应用中对多向振动的适用性。设计了一种多向NES,利用相互正交的两组钢丝绳结构,实现了单振子空间任意方向自适应吸振。基于拉格朗日方程建立了系统多向振动控制方程,采用了谐波平衡法对稳态响应进行近似解析分析,并利用四阶龙格-库塔法进行数值验证,其后研究了多向NES的减振效果。结果表明,多向单振子NES能够有效地抑制多向振动,对任意单向激励也同样有效。该研究为NES在多向振动控制中的应用及设计提供了参考。展开更多
The design of servo controllers for flexible ball screw drives with matched and mismatched disturbances and uncertainties is focused to improve the tracking performance and bandwidth of ball screw drives.A two degrees...The design of servo controllers for flexible ball screw drives with matched and mismatched disturbances and uncertainties is focused to improve the tracking performance and bandwidth of ball screw drives.A two degrees of freedom mass model is established based on the axial vibration characteristics of the transport ball screw,and the controller of an adaptive integral sliding mode is proposed combining the optimal design of state feedback gain matrix K to restrain the vibration and the matched disturbances and uncertainties.Then for the counteraction of the mismatched disturbances and uncertainties,a nonlinear disturbance observer is also developed.The trajectory tracking performance experiments and bandwidth analysis were conducted on experimental setup with the proposed control method.It is proved that the adaptive integral sliding mode controller has a high tracking performance and bandwidth especially for the axial vibration characteristics model of ball screw drives.And the ball screw tracking accuracy also has a considerable improvement with the application of the proposed nonlinear disturbance observer.展开更多
对非线性能量阱(nonlinear energy sink, NES)在汽车传动系统扭振抑制中的应用进行了研究。根据传动系统的结构和振动特点,建立了简化的3自由度传动系统-NES耦合动力学模型;基于增量谐波平衡法联合增量弧长法,推导并求解了耦合系统的频...对非线性能量阱(nonlinear energy sink, NES)在汽车传动系统扭振抑制中的应用进行了研究。根据传动系统的结构和振动特点,建立了简化的3自由度传动系统-NES耦合动力学模型;基于增量谐波平衡法联合增量弧长法,推导并求解了耦合系统的频率响应,利用Floquet理论对周期解的稳定性进行判断;在频域和时域上对系统的非线性动力学响应及其影响因素进行了分析,并基于能量谱研究了NES的减振性能;最后,基于扩展的5自由度非线性模型对NES进行了参数优化和验证。结果表明,NES的减振性能受其自身刚度、阻尼及发动机激励幅值影响,合理设计NES参数可以高效抑制汽车传动系统的扭转共振,而不恰当的NES参数会促使系统发生高分支周期响应,导致异常振动峰值出现,经优化后的NES可以仅5%的惯量比使传动系统转速波动均方根值降低41.3%,减振效果显著。该研究可为NES在传动系统扭振抑制中的应用及其参数设计提供参考。展开更多
基金Project(11972204) supported by the National Natural Science Foundation of China。
文摘The nonlinear vibration of graphene platelets reinforced composite corrugated(GPRCC)rectangular plates with shallow trapezoidal corrugations is investigated.Since graphene platelets are prone to agglomeration,a multi-layer distribution is adopted here to match the engineering requirements.Firstly,an equivalent composite plate model is obtained,and then nonlinear equations of motion are derived by the von Kármán nonlinear geometric relationship and Hamilton’s principle.Afterwards,the Galerkin method and harmonic balance method are used to obtain an approximate analytical solution.Results show that the unit cell half period,unit cell inclination angle,unit cell height,graphene platelet dispersion pattern and graphene platelet weight fraction and geometry play important roles in the nonlinear vibration of the GPRCC plates.
文摘平直机翼和卫星太阳能帆板等结构通常简化为矩形悬臂板,在实际应用中,这些结构通常会面临复杂的弯曲和扭转耦合振动问题,尤其在共振情况下,可能导致结构损伤甚至失效.目前,针对这类结构的共振抑制研究大多集中于弯曲振动的控制,对于弯扭耦合振动的研究相对较少.文章探索了分布式非线性能量汇(nonlinear energy sink,NES)对这类结构弯扭两种共振模式及多个共振模态耦合的抑振效果.首先,基于广义哈密顿原理和牛顿法,建立了含分布式NES胞元的矩形悬臂板弯扭耦合振动的动力学模型.然后,采用伽辽金截断法得到弯扭耦合振动离散方程,并使用谐波平衡法计算稳态响应,利用龙格库塔法进行验证.最后,通过对比不同NES胞元参数的控制效果,讨论了参数对悬臂板结构减振效果的影响规律.研究结果表明,相同NES质量下提高吸振器非线性刚度和恰当阻尼条件下,可以显著提高弯扭耦合振动控制效果.这些结果为矩形悬臂板类结构的弯扭耦合振动抑制提供了新的思路和理论依据,也为该类结构的被动控制策略的优化设计提供了有价值的参考.
文摘非线性能量汇(nonlinear energy sink, NES)在被动控制中有着广阔的应用前景,然而这一领域的研究主要集中在单向吸振器上,这限制了其在实际应用中对多向振动的适用性。设计了一种多向NES,利用相互正交的两组钢丝绳结构,实现了单振子空间任意方向自适应吸振。基于拉格朗日方程建立了系统多向振动控制方程,采用了谐波平衡法对稳态响应进行近似解析分析,并利用四阶龙格-库塔法进行数值验证,其后研究了多向NES的减振效果。结果表明,多向单振子NES能够有效地抑制多向振动,对任意单向激励也同样有效。该研究为NES在多向振动控制中的应用及设计提供了参考。
基金Project(2013ZX04008011)supported by the National Science and Technology Major Projects of ChinaProject(51675100)supported by the National Natural Science Foundation of China
文摘The design of servo controllers for flexible ball screw drives with matched and mismatched disturbances and uncertainties is focused to improve the tracking performance and bandwidth of ball screw drives.A two degrees of freedom mass model is established based on the axial vibration characteristics of the transport ball screw,and the controller of an adaptive integral sliding mode is proposed combining the optimal design of state feedback gain matrix K to restrain the vibration and the matched disturbances and uncertainties.Then for the counteraction of the mismatched disturbances and uncertainties,a nonlinear disturbance observer is also developed.The trajectory tracking performance experiments and bandwidth analysis were conducted on experimental setup with the proposed control method.It is proved that the adaptive integral sliding mode controller has a high tracking performance and bandwidth especially for the axial vibration characteristics model of ball screw drives.And the ball screw tracking accuracy also has a considerable improvement with the application of the proposed nonlinear disturbance observer.
文摘对非线性能量阱(nonlinear energy sink, NES)在汽车传动系统扭振抑制中的应用进行了研究。根据传动系统的结构和振动特点,建立了简化的3自由度传动系统-NES耦合动力学模型;基于增量谐波平衡法联合增量弧长法,推导并求解了耦合系统的频率响应,利用Floquet理论对周期解的稳定性进行判断;在频域和时域上对系统的非线性动力学响应及其影响因素进行了分析,并基于能量谱研究了NES的减振性能;最后,基于扩展的5自由度非线性模型对NES进行了参数优化和验证。结果表明,NES的减振性能受其自身刚度、阻尼及发动机激励幅值影响,合理设计NES参数可以高效抑制汽车传动系统的扭转共振,而不恰当的NES参数会促使系统发生高分支周期响应,导致异常振动峰值出现,经优化后的NES可以仅5%的惯量比使传动系统转速波动均方根值降低41.3%,减振效果显著。该研究可为NES在传动系统扭振抑制中的应用及其参数设计提供参考。
