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为了准确快速地计算齿轮本体温度,本文应用边界元法的原理分析研究了渐开线圆柱直齿轮的本体温度。根据传热学及边界元方法的特点,提出了齿轮模型边界条件的一种简化处理方法,对实例进行了分析计算。比较了边界元法与有限元法的计算结果,两种计算结果基本接近,但前者数据输入量少,可节省大量机时。文中还分析研究了齿轮本体温度的主要影响因素。 相似文献
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论述了边界元法用于含有相变的三维瞬态温度场分析中的理论;详细推导了边界元法用于计算中的公式:对高斯积分计算、时间步长选取及其对计算精度的影响进行了深入的研究;还讨论了多种材料的耦合分析以及相变潜热释放等问题。根据自编的三维瞬态温度场边界元法分析程序所做的数值验证,以及和有限元法计算对比的结果表明:在三维瞬态温度场计算中,边界元法不仅是有效的,而且可以比有限元法得到更好的效果。 相似文献
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在弹性板边界施加假想的弹簧系统模拟板的不同边界条件,利用汉密尔顿函数和瑞利-李兹方法,建立由2块四边弹性支承的弹性板及4块刚性板构成的封闭矩形腔外的辐射声场模型,推导腔体外辐射声场的解析解.该模型考虑两弹性板之间以及弹性板与腔体内声场之间的耦合.算例表明,低频段时两弹性板之间为弱耦合,辐射声场主要由受到外激励的结构所决定;支承板的线弹簧的刚度变化对辐射声场的影响较旋转弹簧大.同时,运用有限元法计算腔体内的声模态和弹性板的振动模态及其耦合系数,结合边界元法计算出腔体外的声压响应,并将此数值仿真结果与前面导出的解析结果进行比较,理论推导的正确性得到验证. 相似文献
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本文采用边界元法计算机器辐射的声场。理论计算和实验验证说明:该法是一种有效的计算方法。本文用此法编制和程序计算了CPQ 2型叉车油泵齿轮箱在主要峰值频率处的表面辐射声场。 相似文献
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《机械强度》2017,(4):754-760
为了对锯切噪声进行定量预估及声场分布规律的研究,提出建立声场、结构、流体多物理耦合模型。利用显式的中心差分算法提取了流固耦合(Fluid Structure Interaction,FSI)作用下多体动态接触时系统的振动响应;基于边界元法-有限元分析建模法搭建了切割系统声学模型,将系统振动响应作为声学边界,对声场辐射进行计算分析。研究了切割系统在半空间环境的声场时域、频域辐射特性;分析了结构与流体间的单、双向耦合对声场的影响;通过计算辐射面积对声功率的影响明确了噪声主要辐射区域。从现场实测数据与数值结果的比较可见,多场耦合分析在切割噪声辐射水平分析及预估方法是正确可行的。 相似文献
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微机电系统中基于模态展开和边界元法的静电-结构耦合高效分析方法 总被引:1,自引:0,他引:1
为了提高微机电系统中静电-结构耦合数值计算速度,提出了一种新的针对微结构小变形的静电-结构耦合高效率数值计算方法。该方法将用于结构分析的微梁线性方程与用于静电场分析的边界积分方程相结合,微梁方程部分用标准的模态分析法处理,静电边界元方程则采用边界元法处理,并且将边界元方程用Taylor级数在微梁未变形的位置展开,以使静电计算能在微梁未变形的位置进行。同以往的常规算法相比,当微结构变形微小时,使用该方法,微结构变形后的面电荷密度可以在微结构未变形中计算,从而大大提高了静电-结构耦合数值计算效率。将该方法的计算结果与已有的文献计算结果和ANSYS的计算结果做了对比,验证了本方法的正确性,并且计算效率有显著提高。 相似文献
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Acoustic-structure sensitivity is used to predict the change of acoustic pressure when a structure design variable is changed.
The sensitivity is significant for reducing noise of structure. Using FEM (finite element method) and BEM (boundary element
method) acoustic-structure sensitivity was formulated and presented. The dynamic response and response velocity sensitivity
with respect to structure design variable were carried out by using structural FEM, the acoustic response and acoustic pressure
sensitivity with respect to structure velocity were carried out by using acoustic BEM. Then, acoustic-structure sensitivity
was computed by linking velocity sensitivity in FEM and acoustic sensitivity in BEM. This method was applied to an empty box
as an example. Acoustic pressure sensitivity with respect to structure thickness achieved in frequency ranges 1–100 Hz, and
its change rule along with stimulating frequency and design variable were analyzed. Results show that acoustic-structure sensitivity
method linked with FEM and BEM is effective and correct.
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Translated from Journal of Vibration Engineering, 2005, 18(3): 366–370 [译自: 振动工程学报] 相似文献
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基于管道振动的模态分析及谐响应分析,计算管道的声辐射效率,建立结构体振动与其辐射噪声之间的关系。文中首先建立管道的圆柱壳模型,进行管道结构动力学分析,采用有限元方法获得结构表面振动速度;然后根据结构声辐射理论,并且采用边界元法离散积分方程,通过建立管道的声场模型,得到管道结构在谐波激励下的声辐射效率,为降低噪声提供理论依据。计算结果表明,本文所建立的振动和声辐射模型及算法是有效的。 相似文献
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针对鼓风机组管路振动噪声问题,应用结构声辐射理论和结构振动测量数据分析振动声辐射强度。以实测振动信号为依据,根据对低频段计算精度较好的边界元理论,应用有限元软件和Sysnoise声学仿真软件建立了实际声场的边界元流体模型和有限元结构模型的耦合模型,得到了模拟声场的仿真结果,并与实测结果进行比较,确定了主要噪声能量来源于管路振动造成的结构振动。通过分析振动的来源以及振动传递的路径和传递特性,确定了隔振降噪的方法。依据理论分析结果,对实际现场采取了有效的隔振降噪方法,隔振后降噪效果明显。 相似文献
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对某离心泵作透平流体诱发的内场噪声特性进行数值计算和试验研究。在典型流量下,采用雷诺时均方法获取壳体壁面偶极子声源,并利用边界元方法(Boundary element method,BEM)求解出壳体偶极子源作用的流动噪声,基于有限元结合边界元的声振耦合法(Finite element method/boundary element method,FEM/BEM)计算出流体激励结构振动产生的内场流激噪声及考虑结构振动的流动噪声,分析不同性质噪声源的频谱特性,同时评估内场声源在各个频段下的贡献量。借助水听器对透平出口进行流体声学试验,获得了噪声的频谱特性。结果表明,离心泵作透平出口流体诱发噪声主要集中在中低频段,小流量工况低频噪声特性增强。壳体声源作用下考虑结构振动流动噪声的计算结果与试验结果在较大流量下吻合较好。壳体偶极子作用的流动噪声对内场噪声的贡献最大,其次是考虑结构振动的流动噪声,流激噪声对内场噪声贡献最小。结构的影响使得二阶叶频处声压增加,其余离散频率及宽频处声压均有所降低。该研究结果为低噪声叶轮机械设计提供了一定的参考。 相似文献
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Finite Element Numerical Simulation and PIV Measurement of Flow Field inside Metering-in Spool Valve 总被引:2,自引:0,他引:2
GAO Dianrong QIAO Haijun LU Xianghui 《机械工程学报(英文版)》2009,22(1):102-108
The finite element method (FEM) and particle image velocimetry (PIV) technique are utilized to get the flow field along the inlet passage, the chamber, the metering port and the outlet passage of spool valve at three different valve openings. For FEM numerical simulation, the stream function ψ -vorticity ω forms of continuity and Navier-Stokes equations are employed and FEM is applied to discrete the equations. Homemade simulation codes are executed to compute the values of stream function and vorticity at each node in the flow domain, then according to the correlation between stream function and velocity components, the velocity vectors of the whole field are calculated. For PIV experiment, pulse Nd: YAG laser is exploited to generate laser beam, cylindrical and spherical lenses are combined each other to produce 1.0 mm thickness laser sheet to illuminate the object plane, Polystyrene spherical particle with diameter of 30-50 μm is seeded in the fluid as a tracing particles, Kodak ES1.0 CCD camera is employed to capture the images of interested, the images are processed with fast Fourier transform (FFT) cross-correlation algorithm and the processing results is displayed. Both results of numerical simulation and PIV experimental show that there are three main areas in the spool valve where vortex is formed.Numerical results also indicate that the valve opening have some effects on the flow structure of the valve. The investigation is helpful for qualitatively analyzing the energy loss, noise generating, steady state flow forces and even designing the geometry structure and flow passage. 相似文献
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采用数值仿真分析方法对航空发动机短环形火焰筒结构进行简化处理,构建短环形火焰筒结构模型。通过有限元方法对结构进行流固耦合分析计算,得到火焰筒壁面温度分布及气动压力分布,计算火焰筒结构热模态结果并分析。通过耦合的有限元/边界元法以扩散场的形式对火焰筒结构施加噪声激励载荷,对火焰筒结构多场耦合非线性动力学响应特性进行分析,获得了短环形火焰筒结构在温度载荷、气动力载荷与噪声载荷耦合作用下的动力学响应规律。 相似文献
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Liang Xinhua Zhu Ping Lin Zhongqin Zhang Yan 《Frontiers of Mechanical Engineering in China》2007,2(1):99-103
A lightweight automotive prototype using alternative materials and gauge thickness is studied by a numerical method. The noise,
vibration, and harshness (NVH) performance is the main target of this study. In the range of 1–150 Hz, the frequency response
function (FRF) of the body structure is calculated by a finite element method (FEM) to get the dynamic behavior of the auto-body
structure. The pressure response of the interior acoustic domain is solved by a boundary element method (BEM). To find the
most contributing panel to the inner sound pressure, the panel acoustic contribution analysis (PACA) is performed. Finally,
the most contributing panel is located and the resulting structural optimization is found to be more efficient.
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Translated from Journal of Shanghai Jiaotong University, 2006, 40(1): 177–180 [译自: 上海交通大学学报] 相似文献