振动工况下剪式可展单元模态分析与结构优化

Modal Analysis and Structure Optimization of Scissor Deployable Element Under Vibration Conditions

为了研究剪式可展单元在振动工况下的响应特性,将船舶除锈装置作为振动源,首先建立剪式可展单元力学模型,并研究极限工况下单元杆件的可靠性;采用数值模态分析方法、随机振动下动应力测试分析方法,研究剪式可展单元在振动工况下产生的随机激励问题及其响应;提出消除剪式可展单元二阶横弯振动与激励共振的方法,并对各结构优化方案进行动应力仿真。结果表明,剪式可展单元二阶模态振动(306.15 Hz)和除锈产生的随机激励共振是引起剪式可展单元振动疲劳的主要原因;将上工作台厚度从10 mm增加到14 mm,上工作台刚度从20 GPa降低到19.5 GPa,同时在两连杆之间加上连接轴,降低单元动应力水平最为明显。论文研究结果可为剪式可展单元在工程应用中稳定可靠工作提供理论基础。

In order to study the response characteristics of the scissor-type deployable element under vibration conditions,the study used the ship rust removal device as the vibration source and firstly established the mechanical model of the scissor-type deployable element.And the reliability of the element members under extreme conditions was studied.Then it used numerical modal analysis method and dynamic stress test analysis method under random vibration to study the random excitation problem and response of the scissor expandable unit under vibration conditions.It proposed a method to eliminate the second-order transverse bending vibration and excitation resonance of the scissor expandable unit and carried out dynamic stress simulation for each structural optimization scheme.The results show that the second-order modal vibration(306.15 Hz)of the scissor-type deployable unit and the random excitation resonance generated by rust removal are the main reasons for the vibration fatigue of the scissor-type deployable unit.The dynamic stress level of the unit can be reduced most significantly by increasing the thickness of the upper worktable from 10 mm to 14 mm,reducing the rigidity of the worktable from 20 GPa to 19.5 GPa,and adding a connecting shaft between the two connecting rods.The research results can provide a theoretical basis for the stable and reliable operation of the scissor deployable unit in engineering applications.