共查询到20条相似文献，搜索用时 171 毫秒
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《实验室研究与探索》2016,(10):12-15
为了得到三等跨曲线连续梁(曲梁)的固有频率和振型,利用Midas有限元分析软件计算了曲梁的固有频率和振型,并对其进行了振动试验。试验结果采用DASP模态分析软件处理,得到曲梁的前3阶频率及振型,将试验结果与计算结果进行对比,证实振型变化的真实性,并对其冲击系数的取值进行了探讨。结果表明:曲梁前3阶频率的相对误差均不超过4%,振型基本吻合;曲梁的有限元计算频率均小于试验实测频率,且曲梁的前3阶频率均小于等跨直梁,刚度是影响同等跨径直梁和曲梁自振频率不同的主要因素。 相似文献
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《实验室研究与探索》2015,(6):128-131
为了得到曲线连续梁的固有频率和振型,以便为桥梁检测提供校核依据;有机地结合了有限元模态分析方法和试验模态分析方法,对某两等跨曲线连续梁进行了模态分析,得到曲梁的前4阶频率及振型,并将试验结果与有限元计算结果进行对比。结果表明:除去一阶频率误差较大外,第2~4阶相对误差均小于4%,振型基本吻合;一阶固有频率受扭转影响较大,第2~4阶频率受扭转影响依次减小;曲梁前4阶频率均小于等跨直梁。 相似文献
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以二维弹性力学问题为研究对象,采用常单元和线性非连续元离散边界积分方程,给出系数矩阵计算的精确表达式。数值实施证实此方法的准确性。和有限元相比,边界元的目的非常明确。它还使数值计算的维数降低一阶,所以计算效率也更高。 相似文献
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以二维弹性力学问题为研究对象，采用常单元和线性非连续元离散边界积分方程，给出系数矩阵计算的精确表达式。数值实施证实此方法的准确性。和有限元相比，边界元的目的非常明确。它还使数值计算的维数降低一阶，所以计算效率也更高。 相似文献
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《实验室研究与探索》2016,(5):10-13
分析计算五等跨连续梁的固有频率和振型,探讨连续梁桥冲击系数与其固有频率和振型的关系,并进行了连续梁振动试验,试验模型采用槽型梁,支撑方式采用钢锟轴支撑,试验结果运用DASP模态分析软件进行处理,得到五等跨连续梁的前5阶振型及频率。利用Midas有限元分析软件对连续梁进行有限元分析,将其计算结果与试验结果进行对比,证实振型变化的真实性。经过试验分析,连续梁的前5阶振型最大曲率位置被确定,结合规范讨论计算冲击系数时结构固有频率的选取。结果表明:当计算跨中正弯矩效应时,冲击系数宜按照《桥规》采用基频计算;当计算中支座负弯矩效应时,冲击系数应采用第3阶频率。 相似文献
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针对频率选择性快衰落信道的多径干扰和较大的多普勒频率扩展,提出了一种基于导频的低维Kalman滤波算法用于正交频分复用(OFDM)系统信道估计.为了简化计算,采用一阶自回归(AR)过程对时变信道进行建模.利用复杂度大大降低的一维Kalman滤波算法进行单个子载波的并行信道估计,并采用基于导频的最小平方(LS)算法估计时变的信道衰减因子a.为了同时跟踪信道的频域相关性,采用了最小均方误差(MMSE)线性合并器对Kalman信道估计结果进行修正.在5.5 GHz频段上的仿真表明了这种基于导频的低维Kalman信道估计方法,降低了传统的Kalman滤波结构的复杂度,能够跟踪信道的时频变化,并且在一定程度上可以接近于理想信道估计的误码率性能. 相似文献
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采用MPICH并行技术，建立了基于PC局域网平台的并行集群系统，并通过VC＋＋6．O调用消息传递库MPI函数编写并行遗传算法，完成了相关并行计算实例。计算结果表明：在现有并行集群系统下能有效地利用现有计算机资源，大幅度提高计算效率，并可获得可观的加速比，为一些复杂问题的求解提供了可行方案。 相似文献
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曾祝明 《常熟理工学院学报》2009,23(4):25-28
利用Hankel矩阵的结构特点导出一递推关系式,给出了Hankel矩阵离散Sine变换（DST）的一个快速算法．该算法所需要的存贮空间为D（N）,计算变换矩阵的肼个元素所需的计算量为O（NlogN）＋O（M）． 相似文献
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In this paper we present a motion compensation （MC） design for the newest Audio Video coding Standard （AVS） of China. Because of compression-efficient techniques of variable block size （VBS） and sub-pixel interpolation, intensive pixel calculation and huge memory access are required. We propose a parallel serial filtering mixed luma interpolation data flow and a three-stage multiplication free chroma interpolation scheme. Compared to the conventional designs, the integrated architecture supports about 2.7 times filtering throughput. The proposed MC design utilizes Vertical Z processing order for reference data re-use and saves up to 30% memory bandwidth. The whole design requires 44.3k gates when synthesized at 108 MHz clock frequency using 0.18-μm CMOS technology and can support up to 1920×1088@30 fps AVS HDTV video decoding. 相似文献
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黄黎明 《贵州教育学院学报》2011,(9):25-28
根据模拟退化算法具有并行性的特点,设计并实现了并行的模拟退火算法,同时以给出不同的初始温度,进行结果的模拟,体现出模拟退火算法的一个特征：初温越大,计算所花费的时间越大。 相似文献
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1 Ｉｎｔｒｏｄｕｃｔｉｏｎ Ｔｈｅｐａｒａｌｌｅｌｄｅｃｏｄｉｎｇｍｅｔｈｏｄｏｆａｐａｒａｌｌｅｌｃｏｎｃａｔｅｎａ ｔｉｏｎｏｆｍｕｌｔｉｐｌｅｃｏｄｅｓｉｓｐｒｅｓｅｎｔｅｄｂｙＤｉｖｓａｌａｒ[1] .Ｔｈｅｉｔｅｒａｔｉｖｅｇａｉｎｏｆｔｈｉｓｍｅｔｈｏｄｎｅｅｄｓｔｏｂｅｃａｌｃｕｌａｔｅｄｂｙｕｓｉｎｇｓｉｍｕｌａｔｅｄａｎｎｅａｌｉｎｇ .Ｗｅｐｒｅｓｅｎｔａｎｅｗｓｅｒｉａｌｄｅ ｃｏｄｉｎｇｍｅｔｈｏｄｗｈｏｓｅｉｔｅｒａｔｉｖｅｇａｉｎｉｓｏｎｅｓｈｏｗｎｉｎＦｉｇ .1.Ｗｅｗｉｌｌ… 相似文献
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Stable response of axisymmetric two-phase water-saturated soil 总被引：1，自引：0，他引：1
Biot's dynamic consolidation equations and Hankel transform were used to derive the integral solutions of stress and displacement for axisymmetric harmonic excitations in the two-phase saturated soil with subjacent rock-stratum. The influence of the coefficient of permeability and loading frequency on the soil displacement at the ground surface were studied. The results showed that higher loading frequency led to more dynamic characteristics; and that the effect of the soil permeability was more obvious at higher frequencies. 相似文献
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Biot's dynamic consolidation equations and Hankel transform were used to derive the integral solutions of stress and displacement for axisymmetric harmonic excitations in the two-phase saturated soil with subjacent rock-stratum. The influence of the coefficient of permeability and loading frequency on the soil displacement at the ground surface were studied. The results showed that higher loading frequency led to more dynamic characteristics; and that the effect of the soil permeability was more obvious at higher frequencies. 相似文献
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This paper presents an analytical layer-element method used to analyze the displacement of a multi-layered transversely isotropic
elastic medium of arbitrary depth subjected to axisymmetric loading. Based on the basic constitutive equations and the HU
Hai-chang’s solutions for transversely isotropic elastic media, the state vectors of a multi-layered transversely isotropic
medium were deduced. From the state vectors, an analytical layer element for a single layer (i.e., a symmetric and exact stiffness
matrix) was acquired in the Hankel transformed domain, which not only simplified the calculation but also improved the numerical
efficiency and stability due to the absence of positive exponential functions. The global stiffness matrix was obtained by
assembling the interrelated layer elements based on the principle of the finite layer method. By solving the algebraic equations
of the global stiffness matrix which satisfy the boundary conditions, the solutions for multi-layered transversely isotropic
media in the Hankel transformed domain were obtained. The actual solutions of this problem in the physical domain were acquired
by inverting the Hankel transform. This paper presents numerical examples to verify the proposed solutions and investigate
the influence of the properties of the multi-layered medium on the load-displacement response. 相似文献
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A new type of ductile lowrise shearwall with many short horizontalkeyways is proposed in this paper in order to improve the earthquake resistant behav-ior of ordinary lowrise shearwall.The behavior of this wall is studied through low-frequency cyclic loading test.Based on the test results,the paper puts forward thedifferent restoring force models for different lowrise shearwalls,and a program fortheir nonlinear dynamic analysis is worked out.Thr(?)h directly inputting earth-quake waves,the paper analyses the dynamic response and energy dissipation of 3types of lowrise shearwalls.The calculation results dem(?)strate that the newly de-vised ductile shearwall has good earthquake resistant behavior. 相似文献
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不通过特征值的计算,直接给出了n阶Hankel矩阵求逆与相乘的一种快速算法,推广了现有的结果。若用FFT计算,其计算复杂性为O(log2n)。 相似文献