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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。
In order to study the vibration characteristics of a new hood equipped with a prototype of a loader, a three-dimensional model of the engine hood was built and modeled by using the finite element method. The natural frequency and The results show that the overall stiffness of the engine cover is low and the distribution of the low order modes is concentrated. Vibration acceleration measurement was carried out on two horizontal and vertical sensitivities of the prototype hood. The range and advantage of the two signal integration methods were contrasted. The acceleration signal was integrated by using the time domain integral method, and the least square method Fitting the trend of the integral signal to be corrected, get the more accurate vibration velocity and displacement signal. Through the comprehensive analysis of the vibration acceleration, velocity and displacement signals in two sensitive directions of the hood, it is judged that the hood stiffness is too low and the vibration amount is too large, and the interference easily occurs. The results of modal analysis and vibration signal analysis provide theoretical basis and improvement direction for the optimization and improvement of the hood samples in the next step.