为研究某装载机样机配置的新型发动机罩的振动特性,利用三维建模建立装载机发动机罩模型并使用有限元法对其进行了模态分析,重点分析了前几个阶次的固有频率和振型,结果显示发动机罩整体存在刚度偏低以及低阶次模态振型分布集中的现象.对样机发动机罩的水平和垂直两个敏感方向进行了振动加速度测量,对比了两种信号积分方法的使用范围及优势,利用时域积分方法对所测加速度信号进行了积分处理,并用最小二乘法拟合积分信号中的趋势项加以修正,得到了较为精确的振动速度及位移信号.通过对机罩两个敏感方向的振动加速度、速度和位移信号的综合分析,判断发动机罩刚度偏低,振动量偏大,易产生干涉.模态分析及振动信号分析结果为下一步发动机罩样品的优化改进提供理论依据及改进方向.%To study the vibration characteristics of the new engine hood for a prototype loader ,the hood model was built by three-dimensional modeling and the modal analysis was conducted with the finite element method (FEM ) .The natural frequen-cies and vibration modes of first few orders were especially analyzed ,and the results showed that the stiffness of the whole hood was inadequate and the low order vibration modes concentrated .The hood vibration accelerations in the horizontal and vertical direction were measured and the using range and advantage of integral method for two signals were compared .The integral pro-cessing of measured acceleration signals was conducted with the time domain integral method ,the trend item of integral signal was corrected with the least square method ,and then the more precise vibration velocity and displacement signal were acquired . Through the comprehensive analysis of hood vibration acceleration ,velocity and displacement signal in two sensitive directions , it was found that the stiffness of the hood was inadequate and the vibration magnitude was large enough to cause interference . Modal and signal analysis results provided the theoretical basis and improvement direction for the engine hood optimization .
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