共查询到20条相似文献,搜索用时 125 毫秒
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介绍受复合载荷作用结构动力分析的背景和意义.从工程应用的角度,探讨温度与随机振动载荷作用下结构动态响应的有限元分析技术,包括对流边界条件下温度场的求解、热应力计算、预应力刚度矩阵的建立、响应功率谱分析等.然后以一种典型多层壳结构为研究对象,根据其在温振复合试验中的受试状态建立有限元模型.在此基础上,采用模态迭加方法和等效黏滞性小阻尼条件,计算复合载荷作用下的振动加速度响应,并与单一振动载荷作用结果进行对比,结果发现,由于环境温度的升高,结构的振动模态频率降低,而振动响应增大.分析结果可作为多层壳结构可靠性试验方法选取的参考依据. 相似文献
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Cymbal型压电堆叠阵列的振动分析 总被引:1,自引:1,他引:0
基于Kirchhoff薄板理论,推导了Cymbal型压电堆叠阵列在周期性均布载荷作用下的等效刚度,利用试验测定了堆叠阵列的阻尼因子,通过模态分析推导了系统的振型频率方程并获得在外部简谐激励下振动位移的一般解.由频率方程计算得到的各阶振型频率与采用有限元方法计算及试验测试的结果基本一致. 相似文献
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为研究核级电动闸阀的抗冲击性能,建立了受设计压力、温度及设计冲击加速度等载荷共同作用的核级电动闸阀有限元模型.利用ANSYS分析软件,对该阀门进行模态分析,结果表明可采用等效静力法分析阀门的抗冲击性能.基于等效静力法,分别分析了阀门在组合载荷冲击作用下的谐响应及静力学特性.谐响应分析结果表明,闸阀系统在承受按简谐规律随... 相似文献
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针对研究采煤机摇臂随机载荷作用下振动响应问题时,频率响应函数H矩阵的求解过程繁琐等问题,文中使用虚拟激励法构造虚拟载荷施加于采煤机滚筒,研究采煤机摇臂在纵向随机载荷作用下的振动响应。使用ADAMS多体运动仿真软件建立摇臂多体运动仿真模型,并进行仿真研究,得到仿真结果略大于理论计算结果。对采煤机截割部进行振动试验测试,所得测试结果略大于仿真及理论计算结果,但是误差在10%以内,能够达到精度要求。通过调整系统各个部件的质量、刚度和阻尼研究其对系统振动响应的影响。结果表明,滚筒质量和滚筒连接梁的刚度对系统振动影响较大,在对摇臂进行设计时要进行合适的优化设计。 相似文献
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非周期激励作用下振动系统的谐响应分析 总被引:1,自引:1,他引:0
用谐响应分析的方法研究非周期激励作用下振动系统的稳态响应。通过精细离散的数值方法实现非周期激励简谐化,表示为有限个简谐激励的组合。分析节点数和采样时间对系数矩阵范数条件数的影响以及算法的误差来源。将微小时间段内的非周期激励简谐化,通过谐响应分析的方法求解每个简谐激励在该时间段内的响应,叠加求和得到其总响应,将该求解策略应用于其他时间段,得到整个时间区域上的振动响应,实现振动系统在多个非周期激励作用下的稳态振动响应分析。设计数值算例,并将数值解和解析解进行对比分析。 相似文献
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《机械工程学报》2017,(9)
基于统计接触理论和等效粗糙接触表面假设,考虑微凸体在加卸载及动态载荷下的变形特征,建立了结合面法向静、动态接触模型,获得了单位面积法向静、动态接触刚度与接触阻尼(基础特性参数)。基于Kadin和Etsion的粗糙表面弹塑性卸载接触模型,通过引入微凸体卸载过程中残余变形与最大变形量及最大接触载荷之间的函数关系,建立静态加卸载接触模型。针对结合面间简谐动态相对位移,利用泰勒公式对静态接触载荷和接触刚度进行展开,得出了动态接触载荷、接触刚度的增量以及动态接触载荷下的能量损耗,建立了法向动态接触刚度和接触阻尼的计算模型。分析了结合面面压、动态位移幅值及振动频率对动态接触刚度和接触阻尼的影响规律,研究表明:法向动态接触刚度相对静态接触刚度有微小偏移增量,动态接触刚度增量和接触阻尼随法向面压及动态位移幅值的增大而非线性增大,动态接触刚度增量随振动频率增加呈非线性增大,而接触阻尼则随振动频率增加呈非线性减小。通过理论计算与试验结果的对比分析,证明了本文建立的结合面法向静、动态接触刚度及接触阻尼理论模型的正确性。 相似文献
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针对目前含金属橡胶的双层隔振系统简谐激励响应算法推导过程复杂、求解困难的现状,提出了基于多项式动态模型的等效线性化方法。首先引入多项式模型对金属橡胶的动态力学特性进行了描述,并对不同频率下隔振系统运动方程中的非线性刚度、阻尼进行等效线性化处理,然后求解方程获得系统在相应频率下的振幅,最后由不同频率的振幅组成幅频特性曲线。通过算例,将利用上述方法得到的结果与试验数据进行了对比,证明了多项式模型等效线性化方法对于含金属橡胶的双层隔振系统简谐激励响应计算问题的适用性、简便性和准确性。 相似文献
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This paper presents a novel approach through the combination of radial basis function (RBF) with Galerkin finite element method (FEM), to determine the solution of journal bearings. We divide the flow field into several subdomains. Local weak integration form of Reynolds equation is developed. The new model uses the point interpolation based on RBF to obtain the shape functions in each subdomain. The global solution is set up on the base of the local solutions of each subdomain. We demonstrate the efficiency and accuracy of the new method in detail using a statically loaded bearing example and by numerical comparisons among RBF method, FEM method and the hybrid method. We found that the large node and element number problem, the large matrix condition number problem, and the shape parameter-sensitivity problem all decrease. We also simulate the self-excited instability phenomenon and unbalance response of a flexible rotor-bearing system with the new model successfully. 相似文献
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Four special cases of Hill's new yield theory (1979) are introduced into a rigid-plastic finite element method (FEM). Comparison between numerical results and experiment shows that the FEM formulation is appropriate for simulating the bulging process of sheet metals. A numerical study of the effects of yield function shape on bulging deformation is carried out. It is found that these effects can be expressed by two characteristic parameters, α and β. Bulging pressure is found to increase linearly as α increases, and the uniformity of strain distribution decreases as β increases. 相似文献
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高精度求解应力强度因子的数值外插法 总被引:7,自引:3,他引:4
首先介绍求解应力强度因子的传统蜕化奇异等参元法和一种新型的数值外插法,两种方法均在裂尖使用精度较高的蜕化奇异二次等参元,考虑到传统方法受裂尖单元尺寸大小,结构物类型,材料泊松比影响较大等缺陷,新方法使用了不同的插值手段。其次,讨论了两种方法插值基础的显著区别,结合空间Ⅰ型裂纹问题论证了新型数值外插法的插值基础,研究了两种方法的理论插值误差,发现本文提出的数值外插法比传统的蜕化奇异等参元法的理论精度高一阶,最后,对两种方法的计算误差进行了探讨。数值外插法考虑到有限元计算断裂问题的误差,能以一定的方式决定不同裂纹问题的优化裂尖单元尺寸。 相似文献
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Hao Wu Qiong Zhou Zhiming Zhang Qi An 《Journal of Mechanical Science and Technology》2012,26(3):653-659
Air blowers are widely used in industry. The vibration of the rolling bearing-rotor is a key factor in the blower’s performance
because it significantly influences the security and working life of the whole system. In previous research on the vibration
characteristics of the air blower, the supporting rolling element bearing was always simplified as a particle on a shaft with
radial stiffness and damping coefficient. Such simplification neglects the effects of the bearing structure on the vibration
performance of the rotor system. In this paper, a numerical model of the bending stiffness of the tapered roller bearing was
established through mechanics and deformation analysis. On the base of the model, a new TMM (transfer matrix method) for bearing-rotor
system was established; the new TMM considers the influences of the bearing structure on the vibration of the rotor system.
Furthermore, modal analysis on an air blower rotor system was carried out by using the new TMM, and the mode shape, critical
speed and unbalance response of the air blower system were obtained. The same blower rotor was also analyzed by FEM to verify
the validation of the new TMM, showing that the new method proposed in this paper for vibration characteristics calculation
of an air blower is credible. 相似文献
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The DMS–FEM, which enables functional approximations with C1 or still higher inter-element continuity within an FEM-based meshing of the domain, has recently been proposed by Sunilkumar and Roy [39], [40]. Through numerical explorations on linear elasto-static problems, the method was found to have conspicuously superior convergence characteristics as well as higher numerical stability against locking. These observations motivate the present study, which aims at extending and exploring the DMS–FEM to (geometrically) nonlinear elasto-static problems of interest in solid mechanics and assessing its numerical performance vis-a-vis the FEM. In particular, the DMS–FEM is shown to vastly outperform the FEM (presently implemented through the commercial software ANSYS®) as the former requires fewer linearization and load steps to achieve convergence. In addition, in the context of nearly incompressible nonlinear systems prone to volumetric locking and with no special numerical artefacts (e.g. stabilized or mixed weak forms) employed to arrest locking, the DMS–FEM is shown to approach the incompressibility limit much more closely and with significantly fewer iterations than the FEM. The numerical findings are suggestive of the important role that higher order (uniform) continuity of the approximated field variables play in overcoming volumetric locking and the great promise that the method holds for a range of other numerically ill-conditioned problems of interest in computational structural mechanics. 相似文献