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中文核心期刊

曲壁蜂窝夹层悬臂板的振动特性研究

VIBRATIONAL CHARACTERISTICS OF HONEYCOMB SANDWICH CANTILEVER PLATE WITH CURVED-WALL CORE

  • 摘要: 蜂窝结构作为一种多孔材料具有轻质、高强度、高刚度的优点, 兼具隔声降噪、隔热等优良性能, 被广泛应用于交通运输、航空航天等领域. 传统直壁蜂窝在受力后容易出现应力集中的问题, 这将导致蜂窝夹层产生裂纹破坏, 缩短夹层板的使用寿命. 针对此问题本文设计了一种以圆弧曲壁蜂窝作为芯层的蜂窝夹层板, 基于单位载荷法推导了蜂窝芯的等效参数, 建立曲壁蜂窝夹层板的动力学模型, 利用Chebyshev-Ritz方法求解悬臂边界下曲壁蜂窝夹层板的固有频率, 并用有限元方法进行对比验证, 发现前5阶固有频率的误差均在5%以内, 每阶固有频率对应的振型一致. 通过3D打印聚乳酸(PLA)制备了曲壁蜂窝夹层板, 使用万能试验机对PLA拉伸试件进行准静态拉伸测定了打印材料的杨氏模量, 搭建振动试验平台对制备的曲壁蜂窝夹层板进行正弦扫频试验、定频谐波驻留试验和冲击试验. 对比发现3D打印模型振动试验获得的前5阶固有频率与理论模型和有限元模型的计算结果三者一致, 试验发现曲壁蜂窝芯在特定频段内具有一定的抗冲击性能. 研究结果将为曲壁蜂窝在振动和隔振方面的应用提供理论支持.

     

    Abstract: As a kind of porous material, the honeycomb structure has the advantages of light weight, high strength, high stiffness, sound insulation, noise reduction, heat insulation and other excellent performance. Therefore, it is widely used in the field of transportation vehicles and aerospace etc. The traditional straight wall honeycomb is prone to stress concentration after loading, which will lead to crack failure and shorten the service life of the honeycombs. In order to solve this problem of honeycombs with straight walls, a honeycomb sandwich plate with circular arc core layer is designed in this paper. The equivalent parameters of honeycomb core are derived based on unit load method and the dynamic model of the curved-wall-core honeycomb sandwich plate is derived. The Chebyshev-Ritz method was used to solve the natural frequencies of honeycomb sandwich plate under cantilever boundaries, and the finite element method is used to compare. The errors of the first five natural frequencies are all within 5% from the two methods. The modes corresponding to each order of natural frequencies obtained from the finite element model are consistent with those obtained from the theoretical model. The curved honeycomb sandwich plate is prepared by 3D printing polylactic acid (PLA). The Young’s modulus of the printed PLA was measured by quasi-static tensile of the tensile specimen using a universal testing machine. The vibration test platform is built to do the sine sweep test, fixed frequency harmonic resides test and impact test. The comparison shows that the first five natural frequencies obtained from the vibration test of the 3D printing model verify the calculation results of the theoretical model and the finite element model. It is found that the curved-wall honeycomb core has a certain impact resistant performance in a specific frequency band. The obtained research results will provide theoretical support for the application of curved wall honeycombs in vibration and vibrational isolation.

     

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