【作者】 丁旭杰；

【导师】 沈荣瀛；

【作者基本信息】 上海交通大学 ， 机械设计及理论， 2008， 博士

【摘要】 设备在工作过程中,不仅受周期性的振动载荷,而且经常还会受到冲击载荷,冲击作用对设备造成的破坏往往比振动造成的破坏更严重。为了减小冲击造成的损坏,必须对设备作冲击防护或隔离。冲击防护和隔离的效果好坏取决于隔离器件的性能和系统参数的匹配。大多数情况下进行系统设计时很少考虑其抗冲击能力,因此对隔振系统的抗冲击性能研究以及新型隔振抗冲击元器件的研究与开发是非常必要的。在十一五海军装备预研项目“新型抗冲隔离器性能、建模理论和开发研究”的资助下,本文对含不同阻尼的单自由度系统的抗冲击性能进行了研究,推导了抗冲击性能指标与系统参数之间的关系,并对不同系统的抗冲击性能进行了比较。以此为基础设计了一种结构新颖的,多机理同时作用的非线性隔振抗冲元件,建立了器件的非线性数学模型,对模型中的待定参数进行了辨识,并对其抗冲击性能进行了研究。论文主要完成了以下几方面的工作:1.论文总结了国内外有关系统在冲击载荷作用下的参数优化问题的研究方法及研究现状以及工程实践中常用的减振抗冲击元器件的作用原理、结构特点、数学模型和它们在各工业领域中的应用,对非线性减振抗冲击器件建模的研究意义、国内外的研究现状、已有的研究成果及存在的问题作了较为全面的论述。2.利用微分方程理论和不等式理论对线性阻尼系统(线性刚度和线性阻尼并联)、平方阻尼系统(线性刚度和平方阻尼并联)以及库仑阻尼系统(线性刚度和库仑阻尼并联)等的抗冲击性能进行了详细的研究。推导了上述系统具有最优抗冲击性能的条件,以及抗冲击性能指标与系统参数之间的关系,导出了系统具有最优抗冲击性能时的系统参数。对不同系统的最优抗冲击性能进行了比较。3.设计了一种多机理共同作用的结构新颖的非线性隔振抗冲元件,器件的回复力由弹性体材料的弹性提供,利用弹性体材料的粘性和接触面间的摩擦来提供阻尼。然后对其进行了有限元建模,利用有限元模型对其关键参数进行了设计。对器件进行了动静态特性仿真,获得了器件的刚度特性—非线性硬特性。4.根据对所设计隔振抗冲器件的仿真结果,建立了两中不同的研究器件振动性能的数学模型,一种是基于力-位移关系曲线的非线性模型,同时将Bouc-Wen迟滞曲线模型引入到非线性隔振抗冲器件的建模中,另一种是基于频率响应曲线的非线性模型,并研究了各模型中的待定参数对器件振动性能的影响。5.提出了所建立振动模型的参数辨识方法,加工制作了试验样机,测试了器件的动静态特性,特性曲线的趋势与有限元仿真结果非常一致,验证了有限元模型的有效性。利用试验数据和辨识方法对模型中的参数进行了辨识。对两种模型在相同初始条件下的自由振动响应和在不同频率下激励的受迫振动响应进行了数值求解,结果表明这两种模型的自由振动的频率非常一致,而受迫振动的振幅基本相同,这说明用这两种模型来模拟器件的振动性能是可行的。6.建立了器件的抗冲击数学模型,计算了在典型冲击脉冲激励下,系统的冲击响应。在跌落试验台上对其进行了冲击性能测试,验证了模型的可靠性。更多还原

【Abstract】 The equipments bear not only the periodic oscillating load but the shock load, and the shock load often does more destruction than vibration itself. To reduce the destruction, it is better to take measures to protect or isolate the equipment. The effect of the protection or isolation depends on the performance of the isolators and the match of the system parameters. In most cases, it does not take the system’s anti-shock ability into consideration when design. So it is necessary to investigate the anti-shock ability of the isolation system and to develop new isolators.Under the support of the project“The study on the performance, theory of modeling and design of new shock isolator”, the author accomplishes the research on performance of the single degree of freedom which contains different damping deduces the relationship between index of anti-shock performance and system parameters, and compares anti-shock performance of the different systems. Based on these, the author designs a novel nonlinear vibration and shock isolator. Then the nonlinear mathematical model of the isolator was established and the parameter of the model was identified.The main research work and conclusions are as follows:1 In the paper, the author reviews some research methods and current research status on the parameter optimization of shock isolation, some common isolators’mechanism, the characteristic of the structure, mathematic model, and their application in industry. 2 Many efforts are put on the anti-shock performance of linear damping system (linear stiffness in parallel with linear damping), quadratic damping (linear stiffness in parallel with quadratic damping) and Coulomb damping system (linear stiffness in parallel with Coulomb damping), deduces the condition when these systems show the optimal anti-shock performance. The optimal anti-shock performance of different systems is also compared.3 A novel nonlinear vibration and shock isolator was designed whose restoring force is supported by the elasticity of the elastomer, and damping force is produced by the viscosity of the elastomer and the friction on contact surfaces. Then the finite element model is built, which is important to confirm the key parameters. The dynamic and static simulation to the isolator shows the stiffness characteristic of the isolator is hard.4 According to the simulation results of the designed vibration and shock isolator, the two nonlinear mathematical models are established to simulate the vibration performance of the isolator. One is based on force-displacement hysteresis curve, and the Bouc-Wen model is introduced to describe the curve. The other is based on frequency response curve. The effect of the parameters of different models to the isolator is studied5 The identification methods to the two models are presented. An experimental sample of the isolator is created, and the characteristic curve is tested which is accordance with the result of finite elements simulation, that validates the validity of the finite element model. Based on these, the unknown parameters of the two models are identified. With these parameters the numerical simulation of the forced vibration response with different original conditions and different excitation frequency are calculated. The result shows that the free vibration’s frequencies of the two models agree well, while the forced vibration amplitudes of the models are consistent. All these prove it is feasible to model the vibration performance of the isolator using the two models referred and the identification methods are valid.6 The nonlinear mathematical model of anti-shock performance is established, and the shock responses of the isolator are caculated under different shock input. The shock experiment is made on the drop test platform, which validates the feasibility of the mathematical model.更多还原