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中速发动机的振动水平对于耐久性、噪声等品质评估标准至关重要。对于为了满足EPA T4排放标准而安装了排气后处理系统的柴油机而言,控制全局振动和局部振动越来越重要、越来越富挑战性。动力总成部件的耐久性不仅取决于曲轴的激振力,还受到结构部件振动的影响。文章介绍发动机全局振动分析方法的目的不是将动态负荷视作离散的静态负荷,而是在包含结构动态响应在内的实际工作条件下计算零部件的可靠性。这种混合分析流程将多体分析(MBA)和有限元分析(FEA)这两种广泛使用的分析方法相结合,可以模拟部件、装配的动态负荷,热力机械负荷,以及局部接触滑移影响。模拟方法在以往大量的发动机零部件基于加速度和应力测量领域经过验证。实际测量和模拟结果对比显示,该方法在全局变形和局部应力方面取得极佳的一致性。
Medium-speed engine vibration levels for durability, noise and other quality evaluation criteria is crucial. Controlling global and local vibrations is increasingly important and challenging for diesel engines equipped with an exhaust aftertreatment system to meet EPA T4 emission standards. The durability of powertrain components depends not only on the crankshaft excitation force but also on the vibration of the structural components. This paper introduces the purpose of engine global vibration analysis method is not to consider the dynamic load as discrete static load, but to calculate the reliability of components under the actual working conditions including the dynamic response of the structure. This hybrid analysis process combines two broadly used analytical methods, multibody analysis (FEA) and finite element analysis (FEA), to simulate the dynamic loading of components, assemblies, thermomechanical loads, and the effects of local contact slip. Simulation methods have been validated in the past for a large number of engine components based on acceleration and stress measurements. The comparison of actual measurement and simulation results shows that the method achieves excellent consistency in global deformation and local stress.