基于模态分析的挖掘机发动机罩结构优化

STRUCTURAL OPTIMIZATION OF THE EXCAVATOR ENGINE HOOD BASED ON MODAL ANALYSIS

挖掘机发动机罩通常由薄板件与加强筋通过焊接而成。在发动机和路面的激励作用下,其薄板结构容易产生严重的振动响应,直接导致结构某些薄弱位置的变形、开裂等问题。利用HyperWorks软件建立了某型挖掘机发动机罩有限元模型,对其进行了模态分析,得到了其在自由状态下的前四阶固有频率及振型,并通过模态实验验证了仿真结果的准确性。依据实验与数值模态分析结果,对该发动机罩进行了结构优化。与原结构相比,优化后发动机罩刚度有所提高,典型振型的最大变形量大幅降低,其动态性能得到明显改善。

Excavator engine hoods are usually formed by welding sheet parts and stiffeners together. Under the incentives of engine and road,the sheet parts are easy to produce serious vibrational response,which directly results in the deformation and the cracking of some weak positions of the structure. The finite element model of an excavator engine hood was established and modal analysis was conducted by using Hyper Works software. Its first four order natural frequencies and corresponding mode shapes in free state were obtained. The accuracy of the simulation results were verified by a modal experiment. Based on the results of the modal experiment and the modal analysis,the structure of the engine hood was optimized. Comparing with the original structure,the stiffness of the optimized engine hood increased and the maximum deformation of typical modes decreased significantly,which indicates that its dynamic performance improves obviously.