查询词典 probability element

The inner force of the line element for underground structure have been calculated using the traditional finite element mesh and high-order manifold method to guarantee the numerical precision of the line element and overcome the disadvantages due to the geometry error between the actual position and computational position of the beam and truss element in common use.

用传统的有限元网格和流形方法的高阶覆盖位移函数来进行地下结构的杆、梁单元计算，保证了线单元模拟的数值精度，同时又克服了常用的杆、梁线单元计算位置与实际位置不相符合从而带来计算误差和结构设计不便等缺点，提供了一种解决结构数值计算的较好的途径。

The theory and the implementation of the genetic algorithms are discussed in detail. The question on how to choose the crossover probability, the mutation probability, the scale of population and the numbers of the generation is discussed. Then, the mathematics model of the optimal design is established. Exerting the finite element of elastic base beam and using FORTRAN to write the GAFORTRAN program. The program includes the common genetic algorithms and the modified genetic algorithms.

详细介绍了遗传算法的理论和实现技术，探讨了交叉概率、变异概率、群体规模、进化代数等变量的选取问题，建立起了基于遗传算法的深基坑支护结构设计的优化模型，结合弹性地基梁有限元法，利用FORTRAN语言编制了GAFORTRAN优化程序，程序中包括普通遗传算法和改进遗传算法。

In the paper, based on the hypothesis that the failure of every poles is independent and by the method of reliability assign and reassign, the difficult problem of disposing the structure system reliability constraints is solved. Based on sensitivity information, the given system failure probability can be replaced by the sum of every element failure probability.

针对基于体系可靠性约束优化设计的关键问题一结构体系可靠性的分析和计算，在基于结构各单元失效相互独立假设的基础上，提出了以各单元失效概率摘要之和近似体系失效概率的处理方法，并给出了体系可靠性分配和再分配的方法，以确保结构体系在优化过程中的可靠性，实现了结构基于体系可靠性的优化设计。

In the paper, based on the hypothesis that the failure of every poles is independent and by the method of reliability assign and reassign, the difficult problem of disposing the structure system reliability constraints is solved. Based on sensitivity information, the given system failure probability can be replaced by the sum of every element failure probability. And then the structural optimization design based on system reliability is preceded.

针对基于体系可靠性约束优化设计的关键问题一结构体系可靠性的分析和计算，在基于结构各单元失效相互独立假设的基础上，提出了以各单元失效概率之和近似体系失效概率的处理方法，并给出了体系可靠性分配和再分配的方法，以确保结构体系在优化过程中的可靠性，实现了结构基于体系可靠性的优化设计。

In this algorithm, the probability of a certain particle element assuming a value of 0 or 1 is in positive proportion to value 0 or 1 of this element in the current position of the particle, the historic best position it experienced, and the best point found by any member of its topological neighborhood; but in negative proportion to value of the former position of it.

在该算法中，每个粒子各元素在新位置取二元值0或1的概率正比例于其当前位置、其历史最优位置和其邻域内的历史最优位置的取值，而负比例于其前一个位置的取值。

Based on the transmission gears, this paper has studied systematically the method of fatigue lifetime prediction under stochastic loads, through probability statistics, finite element and fatigue analysis. The influences of uncertainty of load statistical distribution, finite element model and mechanical performance parameters of material on fatigue life prediction are analyzed.

本文以传动齿轮为研究对象，应用概率统计、有限元和疲劳分析，深入、系统地研究了自行火炮传动齿轮在随机载荷作用下疲劳分析与寿命预测的理论方法，分析了载荷统计分布、有限元模型和材料力学性能参数的不确定性对疲劳寿命预测的影响。

According to the standard and request of mechanical structures for electronic equipment tests, the finite element model of the electronic equipment cabinet was built by using the software of finite element analysis-ANSYS and simulated the tests of random vibrations by loading and calculating. The 3-D isopleths graph of deformation and stress of the cabinet was obtained. It could confirm the maximum of deformation and stress of the cabinet and probability of occurrence. Through more analysis of the frequency response curve reflected directly and clearly the deformation of the cabinet within the particular seismic frequency.

根据电子设备机械结构随机振动试验的标准和要求，采用有限元分析软件ANSYS建立电子设备机柜结构的有限元模型，通过加载求解对其进行随机振动试验的数值模拟，得到机柜有限元模型的三维变形和应力等值线图，进而确定机柜承受应力和变形的最大值及发生概率；通过对频率响应曲线的进一步分析，可以直观明了地反映出机柜承受一定频率范围地震下的变形情况。

An equal cross-section blade was investigated and a finite element model was built parametrically. Geometrical parameters (such as length, width and thickness), material parameters (such as young's modulus and density) and speed of blade were considered as input random variables while the static frequencies and dynamic frequencies were output random variables. Combining the finite element method, response surface method and Monte Carlo method, the statistical properties and cumulative distribution functions of static frequencies and dynamic frequencies were obtained. Probability sensitivities analysis, which combined the slope of the gradient and the width of the scatter range of the random input variables, was applied to quantitatively evaluate the sensitivities of static frequencies and dynamic frequencies with respect to the random variables. The Scatter plots of structural responses with respect to the random input variables were illustrated how to adjust the values of the static frequencies and dynamic frequencies by changing input random variables.

文中以某试验台用汽轮机等直叶片为研究对象，考虑几何参数、材料参数和转速的随机性，通过有限元参数化建模，将确定性有限元方法、响应面方法和Monte-Carlo模拟法相结合，从而获得了叶片静频、动频的统计特性和累积分布函数；同时考虑随机变量的梯度和离散范围对静、动频的影响，通过概率敏感性分析，定量地判断出叶片静、动频对随机输入变量的敏感性；通过绘制叶片静、动频与输入变量的散点图，定量地分析了如何改变随机变量以调整静、动频率的方法。

The basic approach of protecting people from being hurt or killed in an accident is to improve crashworthiness of vehicles. This paper starts with discussing theories and methods for vehicle passive safety design, which included experiential methods, analytic methods, multi-body dynamics methods, crash test methods and the finite element method. Emphasis will be paid to the basic FEM theories and algorithms of impact problems. Topics discussed include the governing equation, element discretization, hourglass control, time integration, material model, shell element algorithms and contact-impact algorithms. For more reliable simulation results, this paper then conducts study on how to accurately get material model parameters by combining the FEM method with experimental method, and develops relevant material test machine and parameter calculating software. Based on that, basic typical impact simulation and test validation study are conducted. On the basis of the above work, the paper studies the thin-shell structures'crashworthiness, which was affected by the following factors: spot-weld features, shell thickness, cross-section and pre-deformation. As to vehicle parts'crashworthiness, the paper conducts simulation study of designing energy-absorbing steering system and adaptive airbag system. A practical energy-absorbing steering wheel is designed as an example. In further depth research, the paper suggests several inverse quantificational methods for vehicle crashworthiness design based on the ideal crash characteristics. The above theories and methods are applied with good results through several practical vehicles' crashworthiness design and improvement.

文中对汽车碰撞安全性的设计理论和方法进行了归类和总结，其中包括经验法、解析法、多刚体动力学法、试验法以及有限元方法等；重点介绍了碰撞有限元法的基本理论和有关算法，涉及到有限元求解控制方程、单元离散、沙漏模态控制、时间积分、材料模型和应力修正、薄壳单元算法以及接触碰撞界面算法等，探讨了有限元计算中的材料模型参数获取技术，开发了相应的材料试验装置及材料模型参数反求软件，在此基础上进行了基本的碰撞仿真算例和试验对比研究；文中通过应用有限元方法研究了薄壁构件的碰撞吸能特性，指出了设计薄壁吸能构件时需要考虑的几个主要影响因素，即焊点、壁厚、横截面和预变形等；在关于车辆部件的碰撞安全性能设计中进行了吸能转向机构和自适应安全气囊的仿真研究，提出了吸能转向机构和自适应安全气囊的仿真研究方法；文中最后探讨了整车碰撞性能的设计与改进方法，提出了以理想碰撞特性为目标，采用分段加速度或者根据碰撞时间进行设计的反推设计法、部件吸能仿真优化设计法等量化设计方法，并通过综合应用文中所讨论的相关技术进行了整车碰撞性能的设计与改进实例研究，所选定的车型是大众化的普通轿车和碰撞安全性基础较差的微型面包车，研究结果表明，本文所提出的设计与改进方法是适用而有效的，具有重要的工程实用意义和价值。

Shadow effect can not be neglected for thermal analysis of spacecraft,Accroding to the angle between solar light and antenna orbit plane and its orbit location,analytical geometry method was used for accurately calculating solar radiation heat flux distribution of reflector surfaces.To analyze the temperature field under heat flux,the formulations of net radiation flux density between two gray elements and the net flux density of gray surface under external thermal flux were deduced.Based on the characteristic of space environment,the nonlinear temperature distribution in transverse direction of reflector shell self radiation were considered,the finite element formulations were given for orthogonal material layered shell by Galerkin method.A layered element including a inner heat source layer was proposed,and the finite element formulation expressed by DOF of the inner heat source layer were put forward with temperature and heat flux boundarys between adjacent layer.

单馈反射面赋形天线是未来星载天线发展的一个重要形式，分析了基于物理光学、几何光学和几何绕射理论的理想反射面辐射场；介绍了基于几何光学的反射面天线赋形方法；针对赋形过程中辐射场的快速分析要求，比较分析了基于物理光学的Fourier-Bessel和Jacobi-Bessel级数展开方法以及GB展开分析方法；利用GB展开快速分析方法在20GHz频率下对0.6m口径的天线进行赋形分析，实现中国大陆的30dB增益覆盖，通过数值计算研究了固定增益期望下的口径尺寸随频率的变化，以及频率为20GHz的不同尺寸天线赋形后的覆盖目标区域最大增益的变化情况。

The statistical analysis of this large set of mutations has led us to propose a diagnostic strategy that should help with the molecular work-up of optic neuropathies.

这一大系列基因突变的统计学分析引导我们提出一个诊断策略，可以帮助我们对视神经病变进行分子学的诊断检查。

The results show that the pipe grouting changes the mechanical parameters of surrounding rocks to achieve the security of engineering objectives by reinforcing surrounding rocks and bolcking the water.

研究表明：小导管注浆一方面改变了围岩的力学参数，另一方面利用浆液的固结特性可以实现堵水和加固围岩的工程目标，使隧道在开挖过程中的安全得到保障。