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1.
本文利用卡尔曼滤波方法对码伪距测量和载波相位测量进行了最优融合,并得到了融合后的伪距测量误差标准差曲线,用融合后的伪距作为观测量和惯导系统进行组合,可以有效地提高导航精度,避免整周模糊度的确定。本文研究了这种组合导航系统,进行了仿真试验,仿真结果表明该组合系统的精度得到了很大的提高,定位精度在1m以内,是一种高精度的导航系统。  相似文献   

2.
冯健  邵立国 《实验力学》1998,13(2):212-217
本文对压力场环境下的光纤应变测量方法进行了研究,在理论上分析了由于测试环境的压力变化产生虚假应变的原因,提出了采用补偿的方法消除虚假应变。通过具有补偿功能的马赫-泽得干涉系统对应变场进行了测量,证明了补偿法的可靠性,为光纤应变测量方法向实用化转变进行了有益的探讨。  相似文献   

3.
抽样定理法重建流场的三维温度分布   总被引:1,自引:0,他引:1  
结合气流场温度较低,只能得到较少干涉条纹的实际情况,提出了采用轴样定理法重建流场的三维温度分布的模型,并考查了该方法的计算机模拟运算结果,对具体的对象,进行了实验,并采用图像处理方法对条纹进行了一系列处理,最后重建了二个截面上的温度分布。  相似文献   

4.
白奇  高山  翟研柯  李煜  姚军峰 《力学季刊》2020,41(1):187-196
本文提出了一种拼接式组合扁梁,对其进行了受弯性能分析.组合扁梁属于内嵌式组合梁,其组成部分较为复杂,传统承载力计算公式偏保守.为便于此类梁的设计,本文在等效应力法的基础上使用等效矩形应力图法,对拼接式组合扁梁的正截面抗弯承载力公式进行推导.使用ABAQUS有限元软件对组合方法公式的准确性进行验证,并与等效应力法公式进行对比,结果表明组合公式得到的数值更为精准.在相同截面高度和用钢量下设计了一个深肋组合扁梁和一个拼接式组合扁梁,并进行了受弯性能对比;同时对不同钢强度和翼缘厚度影响下的拼接式组合扁梁抗弯承载性能进行分析.使用换算截面法对其进行了弹性刚度的计算,并和有限元进行了对比,二者吻合较好,研究结果为拼接式组合扁梁的设计和优化提供了一定参考依据.  相似文献   

5.
大型电力变压器线圈轴向非线性振动研究   总被引:10,自引:0,他引:10  
本文对具有非线性特性的变压器线圈在稳态及短路电动力下的轴向动态响应进行了单自由度和多自由度的理论和数值研究,对提出的安匝平衡时的单自由度力学模型,分别利用多惊讶法和打靶法进行了稳态响应的解析和数值分析,并对打靶法中差商阵的求法进行了改进,减少了计算工作量,对于典型的单柱式变压器线罪状系统建立了非线性多自由度模型,进行了短路响应数值分析,得出了响应特征及其和变压器各参数之关系,同时,进行了模型变压器短路试验,进行了轴向动态响应力等一系列测量,分析结果与试验结果相符。  相似文献   

6.
本文对油田用新式螺杆泵的柔性抽油杆的扭转与伸缩进行了非线性分析,给出了应力、位移、扭转角的精确公式;进行了屈曲和塑性分析,并对现有抽油杆进行了数字计算,所得结果可供设计与安装参考。  相似文献   

7.
微力矩导弹舵机负载模拟器的理论研究   总被引:1,自引:0,他引:1  
以某型号反坦克导弹舵机为对象,对一种称之为微力矩负载模拟器进行了研究。根据该型号导弹舵机的特点,对系统关键元件的选择设计进行了分析,建立了系统的数学模型,并通过分析多余力矩的产生机理,对系统进行了多余力矩补偿和校正,最后进行了仿真分析。  相似文献   

8.
本文用弹塑性有限元对双层卷焊管的成型过程进行了模拟,发现了管坯在成型过程中的变形规律及特点。利用计算机采样及磁带机记录等现代化测试手段对双层卷焊管的成型过程进行了多点同时测量,并将实测值与有限元结果进行了比较,两者基本一致  相似文献   

9.
用数字散斑相关法研究聚氨酯泡沫塑料的压缩力学性能   总被引:3,自引:0,他引:3  
提出了一种改进的数字散班相关计算方法,使其能直接进行应变迭代,灵敏度可达1000με,并对它进行了验证试验。对于两种不同密度的聚氨酯泡沫塑料,采用改进的数字散斑相关法对其压缩力学性能进行了测试,得到了其应力——应变关系及弹性模量等力学参数。  相似文献   

10.
本文根据弹性力学的基本理论,以薄板模型为基础,对大型变压器箱壁平板耐压试验进行了受力分析,导出了各种条件下变形和应力计算公式,最后对计算模型适用性进行了讨论。  相似文献   

11.
A holographic method for reconstructing the polarization of light emitted by a photoelastic model is presented. Isochromatic and the entire family of isoclinic fringe patterns may be obtained by examining the holographic image, a posteriori. This is accomplished by using two orthogonally polarized reference beams so arranged that the reconstructed crosstalk images do not overlap. An analysis is preseted crosstalk images do not overlap. An analysis is presented which shows that, to reconstruct polarization, the phase relationship between the two reference beams must be maintained. This requirement is more stringent than that normally required in holography. Experimental verification is presented.The use of double-exposure holography to obtain isopachic-isochromatic fringe patterns in the reconstructed image is discussed. An analytic treatment of the method is presented. Expressions relating the isopachic-isochromatic fringe pattern in the reconstructed virtual image to the principal stresses are developed. Differences between this analysis and that presented in a recent paper are discussed. Experimental results are obtained and compared to theory and to other experimental results with good agreement.Paper was presented at 1969 SESA Spring Meeting held in Philadelphia, Pa., on May 13–16.The study reported herein was supported in part by NASA Grant No. NsG-401.  相似文献   

12.
A new and simple method is presented to determine the inde-pendent shear modulus of transversely isotropic material.Mathematical formulation,derivation and solution are given,and test apparatus and results are presented.The method wastested on one of such materials-Green River Formation oilshale.Comparisons wich other approximate results and acou-stical methods are made.Confirmation of the test methodwith materials having known shear moduli is also presented.  相似文献   

13.
A semi-numerical method is presented for solving the inverse heat conduction problems in homogeneous and composite bodies. The presented solution does not require both the initial temperature distribution in the body and the whole temperature-time history at the temperature sensor locations. Sample calculations confirm that this approach produces stable and accurate results for both exact and noisy data. The extension of the method presented to two or three dimensions is straightforward.  相似文献   

14.
Based on the classical response surface method (RSM), a novel RSM using improved experimental points (EPs) is presented for reliability analysis. Two novel points are included in the presented method. One is the use of linear interpolation, from which the total EPs for determining the RS are selected to be closer to the actual failure surface; the other is the application of sequential linear interpolation to control the distance between the surrounding EPs and the center EP, by which the presented method can ensure that the RS fits the actual failure surface in the region of maximum likelihood as the center EPs converge to the actual most probable point (MPP). Since the fitting precision of the RS to the actual failure surface in the vicinity of the MPP, which has significant contribution to the probability of the failure surface being exceeded, is increased by the presented method, the precision of the failure probability calculated by RS is increased as well. Numerical examples illustrate the accuracy and efficiency of the presented method.  相似文献   

15.
周鹏  续伯钦 《实验力学》1997,12(2):180-185
本文引入带窗正交基变换对正弦空间载波条纹图和二值空间载波条纹图进行了分析,并给出了实验验证  相似文献   

16.
An LDV system for making spatial correlation measurements of velocity fluctuations in turbulent nonreacting and reacting flows is presented. The LDV system is the dual beam type and consists of an elongated probe volume and a two-point optical fiber detector. Results are presented of the integral length scale measured in a nonreacting grid generated turbulent flow.A version of this paper was presented at the ASME Winter Annual Meeting of 1984 and printed in AMD, Vol. 66  相似文献   

17.
An experimental study is presented which details the turbulence characteristics of a two dimensional offset jet. A single offset ratio (height of the nozzle above the solid parallel wall by nozzle width) of seven is used with a nozzle Reynolds number of 15,000. Measurements are presented in the preattachment jet region made with a dual frequency shifted laser Doppler anemometer. The relative strain rates resulting from curvature on the upper and lower sides of the jet are determined and their effects on the r. m. s. fluctuating velocity components are presented.This paper was presented at the Ninth Symposium on Turbulence, University of Missouri-Rolla, October 1–3, 1984  相似文献   

18.
A new, room-temperature formulated, epoxy-resin system with superior stress-freezing photoelastic properties is presented. The ease of producing relatively large, high-quality, precision castings is discussed. Stress-optical, rheological, and mechanical properties are given. Cylindrical tubes joined by integrally cast Stub Acme and American Standard rolled thread profiles with typical geometric parameters are loaded in tension and analyzed using the stressfreezing method. Results are presented for surface axial stress distributions for the wall surfaces opposite the threaded profiles. Additionally, the fillet stress distribution for the first engaged thread as a function of the distance along the thread helix from the location of initial contact is presented. Comparison with a finite-element analysis is given. Paper was presented at the 1983 SEM Spring Conference on Experimental Mechanics held in Cleveland, OH on May 15–19.  相似文献   

19.
A method is developed to solve elliptic singular perturbation problems. Examples are presented in one and two dimensions for both linear and non-linear problems. In particular, examples are presented for fluid flow problems with boundary layers. In the one-dimensional case an approximating equation is developed using just three points. The method first presented is a fourth-order approximation but is extended to become a higher-order method. Results are included for the fourth-, sixth-, eighth- and tenth-order methods. The results are first compared with results found by Segal in an article about elliptic singular perturbation problems. The elliptic singular perturbation problems are compared with a method by Il'in and also with central and backward difference schemes from Segal's article. There was only one case where the results in Segal's paper were as accurate as the results presented in this paper. However, in this case the method used by Segal did not give accurate values for a second problem presented. The results are also compared with results given by Spalding and by Christie. The method of this paper was also tested on the solution of some non-linear diffusion equations with concentration-dependent diffusion coefficients. The results were superior to results presented by Lee and by Schultz. Finally, the method is extended to several two-dimensional problems. The method developed in this paper is accurate, easy to use and can be generalized to other problems.  相似文献   

20.
IntroductionManyscholorshavediscussedthesolutionofthetwo_dimensionalPoissonequation .AmatrixdiagonalizationmethodwasdevelopedbyHaidvogelandZang[1]forthesolutionofthetwo_dimensionalPoissonequation .Thismethodisefficientbutrequiresapreprocessingcalculatio…  相似文献   

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