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1.
由于空间站核心舱的声源频谱特性、结构形式、材料属性等非常复杂,整个预示模型可能出现子系统模态密度差异较大的情况,单一的有限元方法或统计能量分析法均不能对整个系统的声振环境进行有效评价。本文基于FE-SEA混合法,建立整舱复杂声振耦合精细化噪声仿真模型并仿真,得到舱内的"中频"噪声水平特性分布。结果表明,基于FE-SEA混合模型所得声压级曲线在全频域普遍高于单纯采用统计能量模型计算的结果;尤其在160Hz附近,睡眠区的FE-SEA模型结果要远大于SEA模型的结果。  相似文献   

2.
车内噪声FE-SEA混合建模及分析方法   总被引:1,自引:0,他引:1  
对二子系统的互易关系进行了阐述,并通过模态方法别对二子系统的互易关系进行了介绍,并介绍了两个面连接子系统的耦合关系,最后给出了混合FE-SEA的系统方程。建立了轿车FE-SEA混合模型,对FE车身的辐射效率进行了计算,通过试验对动力总成悬置激励和车身悬置激励进行了测量,在消声室内对发动机舱声辐射激励进行了测量,建立了CFD风洞仿真模型,并对车外风激励进行了计算,同时通过施加激励后的混合FE-SEA模型对车内噪声进行了预测,并与试验结果进行了对比,并对误差产生的原因进行了分析,对比分析结果表明,二者有着较好的一致性,预测绝对误差小于2.5 dB(A),计算精度满足工程要求,混合FE-SEA建模方法是一种有效的车内中频噪声预测方法。  相似文献   

3.
FE-SEA混合法将计算低频响应的有限单元法和计算高频响应的统计能量分析结合起来,可用于全频段的结构振动响应分析.将FE-SEA混合法运用到梁结构的弯曲振动分析中,研究了计算整体动力刚度阵Dgg原理,推导了修正的动力刚度阵ΔD、修正的力阵ΔF以及整体模态的输入功率Pg在梁弯曲振动分析中具体的表达式.最后利用计算机仿真对三种耦合情况进行了仿真,并利用FEA和SEA方法的计算结果,证明了FE-SEA混合法运用于梁结构弯曲振动响应分析的正确性.与传统的有限元法相比,FE-SEA混合法的计算量大大减小.  相似文献   

4.
平台支持船由于作业需要通常配备有动力定位系统,其在侧推工况下舱室噪声超标较为严重。针对这个问题采用计算流体力学(CFD)方法,得到侧推螺旋桨作用在导管上的脉动压力,并将时域计算结果转换成噪声计算的激励条件。采用有限元(FE)与统计能量分析(SEA)混合方法建立船体中频段FE-SEA耦合模型并建立船体高频段SEA模型,对某65 m AHTS船侧推工况下全频段(63 Hz~8000 Hz)舱室噪声进行预报,分析该船噪声分布规律及主要影响因素。并建立起全船的SEA模型,在中频段对比SEA与FE-SEA两种方法得到的舱室声压级频谱曲线,验证了使用混合模型的必要性。  相似文献   

5.
针对梁板组合结构的中频振动问题,在混响实验室中进行某一典型梁板组合结构的声振试验,对试验获取的梁和板的加速度响应进行了分析,基于H-混合模型法建立了有限元-统计能量(FE-SEA)混合模型,通过模态试验对模型进行了验证。对混合模型计算的结果进行了分析,并与试验结果进行了对比。得到了内外声场之间通过板结构进行非共振传递和共振传递的声传递规律。FE-SEA混合模型计算与试验结果吻合,验证了使用H-混合模型方法进行中频振动分析的有效性和可靠性。  相似文献   

6.
基于FE-SEA混合方法的声腔内部噪声预测   总被引:2,自引:1,他引:1  
对二子系统的互易关系进行了阐述,给出了混合FE-SEA的系统方程。通过数值仿真,建立了声腔-平板-声腔系统的FE-SEA混合模型,同时建立了声腔-平板-声腔系统的SEA模型,对声腔模态密度、SEA模型中声腔与板的耦合损耗因子进行了计算,同时计算了FE板与SE板的辐射效率,并对2个模型进行了响应计算,分析了误差产生的原因,并将FE-SEA模型与SEA模型计算结果进行了对比,对比结果表明,二者在中高频段具有较好的一致性。同时还建立了声腔-轿车后风挡玻璃-声腔系统的FE-SEA混合模型,以及该系统的SEA模型,通过试验对内侧声腔激励进行了测量,计算了FE-SEA模型与SEA模型外侧声腔的响应声压级,并与试验结果进行了对比,对比结果表明,在中高频段FE-SEA模型与SEA模型的预测结果相吻合,且FE-SEA模型与试验结果有着较好的一致性。  相似文献   

7.
为研究某车型风窗噪声,根据格子波尔兹曼(Lattice Boltzmann,LBM)方法获得高速行驶工况下车身表面各监测点处的1/3 倍频程声压级及平均输入激励。采用混合有限元-统计能量分析(Finite Element-Statistical EnergyAnalysis,FE-SEA)方法对该车型车内噪声进行输入激励下的数值模拟,得到驾驶员耳旁声压级结果,并与实车道路试验比较,验证了该方法的可靠性。仿真结果表明,在20 Hz~125 Hz范围内,混合FE-SEA方法精度高于统计能量分析(Statistical Energy Analysis,SEA)方法;在125 Hz~400 Hz中频范围内,根据混合FE-SEA方法所得结果与道路试验结果更为吻合,与试验结果的误差最大值不超过3 dB;在400 Hz~1 000 Hz范围内,SEA方法的精度逐渐提升,其计算结果与试验值吻合度升高。据此进行的车身部件贡献量分析表明左前侧窗在整个频段内都对驾驶员耳旁噪声有影响, 左后侧窗对其贡献量最小。  相似文献   

8.
针对高速列车车体结构刚度大,结构复杂的特点,采用混合FE-SEA方法建立基于混响室以及混响室-消声室的两种隔声量预测模型,通过仿真结果对比,两种模型预测的隔声量结果相同,将仿真结果与实测值对比,结果表明,在100 Hz~1 000 Hz的中频范围内FE-SEA模型的预测结果与试验结果吻合良好,混合FE-SEA方法可以有效用于高速列车车体结构的隔声量预测。  相似文献   

9.
基于混合FE-SEA法,对汽车前围声学包成型件中频插入损失进行仿真计算。根据厚度分布云图将声学包成型件按三种不同的方式(粗划分、中划分、细划分)进行区域划分;结合试验与仿真方法获取与声学包声学性能相关的材料物理参数(孔隙率、流阻、弯曲度、黏性特征长度、热力特征长度等);根据声学包成型件的三种区域划分方式建立三种前围声学包的混合FE-SEA模型,并通过对仿真结果与试验结果进行对比确定最优划分方式以及此方式的混合模型在中频的有效频率区间。结果表明,此混合模型的仿真结果与试验结果在200 Hz~630 Hz频段内具有较好的一致性。  相似文献   

10.
为研究湍流脉动噪声激励下复合材料层合板的传声特性,首先基于一般层合板理论将复合材料层合板等效为单层各向异性板,进而采用FE-SEA混合方法研究其传声损失。同时开展复合材料层合板传声损失试验,并将FE-SEA结果和统计能量法(SEA)结果以及实验值进行对比分析。研究结果表明:FE-SEA结果和实验值整体上分布趋势一致,而且误差也相对较小,其中3 000 Hz~10 000 Hz误差在2 dB以内,但由于刚度等效导致2 000 Hz附近结果误差相对较大。相较于SEA方法, FE-SEA混合方法综合考虑了复合材料层合板边界条件和详细得几何特征,不仅可以准确地计算复合材料层合板的固有特性,而且使得传声损失结果在全频带内与试验值吻合得更好。因此建立的二维等效FE-SEA混合模型可以准确预示复合材料层合板在湍流脉动噪声激励下的传声损失。  相似文献   

11.
采用FE - SEA混合法,建立飞机舱室内噪声预测模型,提出飞机舱室的子系统划分方法,并开展4种不同激励条件下舱内噪声中频噪声预测研究。通过仿真和实验结果的对比分析,验证FE - SEA混合法在预测舱内中频噪声方面的准确性和有效性。分析结果表明:FE-SEA混合法能够比SEA方法更有效地预测舱内中频段的噪声。  相似文献   

12.
提出了一种混合FE-SEA模型用于预测机械激励下声学包装的中频段插入损失,与验证试验进行对比,其准确性得到了验证。基于此模型,通过改变两种典型的声学包装的设计参数,得到了其插入损失随设计参数变化的规律,即决定插入损失峰谷值频率特性的敏感要素是对整体模态特性影响最大的参数;最后给出结论,当机械激励下的结构声传播为主要传播路径时,板件应选择覆盖层为均匀质量层的声学包装  相似文献   

13.
Using the Stochastic Finite Element Method (SFEM) to perform reliability analysis of the free vibration of composite plates with material and fabrication uncertainties has received much attention lately. In this work the stochastic analysis is performed using the First-Order Reliability Method (FORM-method 2) and the Second-Order Reliability Method (SORM). The basic random variables include laminae stiffness properties and material density, as well as the randomness in ply orientation angles. Modeling of the composite behavior utilizes a nine-noded isoparametric Lagrangian element based on the third-order shear deformation theory. Calculating the eigenvectors at the mean values of the variables proves to be a reasonable simplification which significantly increases solution speed. The stochastic finite element code is validated using comparisons with results of Monte Carlo simulation technique with importance sampling. Results show that SORM is an excellent rapid tool in the stochastic analysis of free vibration of composite plates, when compared to the slower Monte Carlo simulation techniques.  相似文献   

14.
A parametric study of dynamic recrystallization was undertaken using the Monte Carlo method. Cells in the simulation domain were connected to six neighboring cells across interfaces whose energy varied from 0 to 5 depending on the difference in orientation between the cells. The internal energy of cells was increased during each Monte Carlo step (MCS). A cell was allowed to grow (take up the orientation of one of its neighbors), recrystallize (take up a new orientation), or remain unchanged. Three different energy input rates were used in the simulations. Results presented include the effect of energy input rate on the internal energy, boundary energy, nucleation and growth events, and the structural evolution of the domain. Some comparisons are made with phenomenon observed during dynamic recrystallization of metals.  相似文献   

15.
For the reliability analysis of engineering structures a variety of methods is known, of which Monte Carlo (MC) simulation is widely considered to be among the most robust and most generally applicable. To reduce simulation cost of the MC method, variance reduction methods are applied. This paper describes a method to reduce the simulation cost even further, while retaining the accuracy of Monte Carlo, by taking into account widely present monotonicity. For models exhibiting monotonic (decreasing or increasing) behavior, dynamic bounds (DB) are defined, which in a coupled Monte Carlo simulation are updated dynamically, resulting in a failure probability estimate, as well as a strict (non-probabilistic) upper and lower bounds. Accurate results are obtained at a much lower cost than an equivalent ordinary Monte Carlo simulation. In a two-dimensional and a four-dimensional numerical example, the cost reduction factors are 130 and 9, respectively, where the relative error is smaller than 5%. At higher accuracy levels, this factor increases, though this effect is expected to be smaller with increasing dimension. To show the application of DB method to real world problems, it is applied to a complex finite element model of a flood wall in New Orleans.  相似文献   

16.
V. G. Petrov 《Acta Mechanica》1987,70(1-4):127-143
Summary The two gas-kinetical simulation methods, the molecular dynamics method and the direct simulation Monte Carlo method, are used to calculate the Oseen vortex decay. The simulation solutions are compared with the analytical solution of the Navier-Stokes equation, this allowing examination of the influence of method-specific parameters on the simulation solution, particularly in relation to the conservation of angular momentum.The results obtained with the molecular dynamics method near the limit of the continuum-mechanical regime correlate very well with the analytical solution, the angular momentum being conserved exactly, due to the nature of the method. The direct simulation Monte Carlo method can also be used to simulate the vortex decay, provided that suitable parameters are selected. In this case, however, the angular momentum is not conserved exactly, due to the statistical assumptions. One of the objectives of this work is to optimize the Monte Carlo simulation method in relation to the conservation of angular momentum.With 10 Figures  相似文献   

17.
A novel method named optimization-oriented exponential-polynomial-closure approach is proposed in this article. The main idea of this attempt is to extend the original exponential-polynomial-closure solution procedure methodologically by minimizing the resulted residual error square of the governing equation, which is achieved after an exponential polynomial is adopted as the approximate solution. The objective function for computing the parameters in the approximate solutions of nonlinear random oscillators is then formulated. The probabilistic solutions of the oscillators obtained by the presented approach are verified by the exact solutions in some special cases or by Monte Carlo simulation. Numerical examples indicate that the solutions attained by the presented approach match with the exact or Monte Carlo simulation solutions. The advantage of the presented solution procedure is that it can provide a much more accurate solution than the Equivalent Linearization approach and it is much more efficient than Monte Carlo simulation as demonstrated by the numerical examples.  相似文献   

18.
Brute force Monte Carlo simulation methods can, in principle, be used to calculate accurately the reliability of complicated structural systems, but the computational burden may be prohibitive. A new Monte Carlo based method for estimating system reliability that aims at reducing the computational cost is therefore proposed. It exploits the regularity of tail probabilities to set up an approximation procedure for the prediction of the far tail failure probabilities based on the estimates of the failure probabilities obtained by Monte Carlo simulation at more moderate levels. In this paper, the usefulness and accuracy of the estimation method is illustrated by application to a particular example of a structure with several thousand potentially critical limit state functions. The effect of varying the correlation of the load components is also investigated.  相似文献   

19.
An efficient numerical approach is presented for the simulation of mold filling process with random fibrous permeability as input. Suitable dimension-reduction techniques are employed to represent all the random fields in the physical system. The required accuracy in tracking the moving resin flow front is guaranteed by the Level Set Method (LSM). The Probabilistic Collocation Method (PCM) is applied in the efficient solution of the non-linear stochastic system. Numerical examples for different injection schemes are presented to demonstrate the cost-effectiveness of the current approach in predicting the variability in mold filling results in comparison to the traditional Monte Carlo Simulation (MCS).  相似文献   

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