利用FEPG进行Navier-Stokes方程的有限元程序的生成

通过有限元生成系统(FEPC)产生了粘性不可压流体Navier-Stokes方程的有限元程序.为了克服计算上的困难,利用算子分裂法将N-S方程表述的物理过程分解为扩散和对流两个过程.导出了扩散方程的弱形式,进而建立起它的有限元方程,利用最小二乘法建立起对流方程的有限元方程.利用所产生的程序对二维的粘性不可压流体的绕圆柱流动问题进行了数值模拟.     

心理因素影响下游客节假日错峰旅游出行行为研究

错峰出行是解决出行时间集中引起交通拥堵问题的重要措施. 本文以节假日游客错峰出行行为为研究对象,探究心理潜变量对其错峰出行意向及行为的影响机理. 基于计划行为理论,同时考虑节假日旅游满意度,构建节假日游客错峰旅游出行行为的结构方程模型. 定量研究了态度、主观规范、知觉行为控制、节假日旅游满意度4 个心理因素对游客节假日错峰旅游行为意向及行为的影响. 最后通过问卷调查数据进行了实例分析. 研究结果表明,4 个潜在变量对节假日错峰旅游出行行为意向具有显著影响,其中知觉行为控制是关键因素且影响最大,节假日旅游满意度对节假日错峰出行行为意向及行为有显著负向影响. 本研究可为节假日游客错峰旅游出行措施的制定提供参考依据.     

老年人对自动驾驶汽车接受度研究

有限的交通方式选择使得老年群体出行的机动性、便捷性和可达性往往难以得到充分的满足,这会极大影响晚年生活的幸福感,为解决这一问题,针对老年群体的出行行为研究受到了广泛关注.自动驾驶汽车作为一种新兴出行方式,能够提高老年群体出行机动性,这一新兴出行方式得以普及的前提条件之一在于广大老年群体是否能迅速且广泛地接受.因此,在自...     

低载强化对高强度汽车零件疲劳性能的影响

通过试验研究了不同等级低幅载荷对某汽车齿轮单齿弯曲疲劳性能的影响,发现一定范围内的低幅载荷对单齿弯曲疲劳强度的强化效果确实存在,并且比较显著。在疲劳试验结果的基础上,通过数值插值方法,补充了试验数据,得到强化载荷与强化后疲劳寿命之间、强化次数与强化后的疲劳寿命之间的数学关系,并基于这两个二维关系式拟合得到低幅交变载荷作用下的三维强化曲面方程。     

线性模型下摄像机标定

主要讨论线性模型下控制点的选取方法。基本原理建立在对超定方程组系数矩阵的讨论上。理论推导和图像实验表明本讨论结果是有效的,具有一定的实用价值。     

SBS改性沥青老化过程性能预测方程研究

建立SBS改性沥青在老化过程中性能衰变的非线性预测方程，通过薄膜烘箱试验验证了预测方程的可靠性，基于预测方程分析了SBS改性沥青老化过程中性能指标的变化速率。研究结果表明，非线性方程x(t)=(Lx₀)/[1+(L-1)e^-rt]可用以预测针入度、软化点、延度在SBS改性沥青老化过程中的变化规律；沥青针入度、软化点、延度的变化速率随老化时间的延长而逐渐下降，其中延度指标在老化初期的变化速率下降最快；可通过建立宏观性能指标与红外光谱a₁₇₀₀/a₁₆₀₀的关系方程，进行SBS改性沥青老化程度的预测评估。     

锚链多体系统最优化求解方法及其对比分析

为了在不添加额外方程或判断条件的情况下，求解锚链多体系统悬链和卧链共存的状态，提出利用最优化原理描述静态锚链多体系统的状态方程，即最小势能方程，并与传统的悬链线方程和多体系统一般力学方程进行对比分析。结果表明，该方法不需要进行复杂的受力分析，形式简单且物理意义明确。数值计算结果与传统方法在计算悬链时是一致的，且可在统一的框架下计算悬链和卧链同时存在的状态。     

An improved method for estimating internal solitary waves force on small circular cylindrical structures

Theoretically calculation and laboratory experiments were performed to investigate the horizontal force exerted by internal solitary wave (ISW) on small circular cylindrical structures. Improvement in calculation of drag force and inertia force by introducing two-drag-coefficient method and spatial derivative of velocity into the calculation of force by eigenfunction was made based on systematically study on theoretical foundations. Particle image velocimetry (PIV) method and high precision force sensor were used to measure the velocity and force exerted by ISW, respectively. ISW waveform was traced by analyzing image frames follow grayscale threshold method. For the first time, components of horizontal force were calculated from PIV data, which show good agreement with theoretical one. Moreover, series comparisons between experimental data and calculational results were carried out to examine the proposed method. The results show ideal accuracy of the method and significant improvement comparing to the traditional method.     

Numerical method of electromagnetic pulse response of conductor with complex load北大核心CSCD

[Objectives]Electromagnetic pulse can seriously affect and even destroy naval shipborne electronic information systems, weapons, equipment and so on. Due to the complexity of the antenna port load circuit, it is necessary to formulate a numerical method which can easily obtain the antenna load current. [Methods]The induced current of the terminal is obtained on the basis of the finite-difference time-domain (FDTD) and Holland model. According to the Thévenin equivalent circuit, the conductor is equivalent to the voltage source to realize decoupling between the conductor and load end, and the load circuit is solved using Simulink software.[Results]Compared with the traditional terminal model, this method is simple and feasible for high-order circuit processing. The effectiveness of the model is verified using non-linear elements and parallel capacitors and resistors as the load respectively. The results show that the calculation results of this method are consistent with those of the traditional methods. Finally, the antenna of the end-connected protect- or is calculated. The results show that the lead inductance caused by the installation of the protector is an important factor affecting the protection performance.[Conclusions]The method proposed in this paper can greatly reduce the simulation complexity of the coupling current of an antenna with a complex load, giving it useful reference value for the field of ship electromagnetic pulse protection design. © 2023 Editorial Department of Chinese Journal of Ship Research. All Rights Reserved.