COMBINATORIAL OPTIMAL ALGORITHM FOR SENSOR ARRANGEMENT IN STRUCTURAL HEALTH MONITORING SYSTEM

在对结构健康监测中的传感器优化布置方法进行调研和总结的基础上,针对薄板、壳结构开展传感器优化布置的研究.提出了一种有效的传感器优化布置组合算法,由模态动能法、模态保证准则、遗传算法组合而成.该方法所得的传感器位置主要位于动态响应比较大区域,有利于提高信噪比;同时能够有效地保证模态振型的独立性,可以较完整地获得结构模态信息.针对这种组合算法的有效性采用简易机翼模型从数值计算和实验两方面进行了验证

结构健康监测系统中传感器优化布置组合算法

在对结构健康监测中的传感器优化布置方法进行调研和总结的基础上，针对薄板、壳结构开展传感器优化布置的研究．提出了一种有效的传感器优化布置组合算法，由模态动能法、模态保证准则、遗传算法组合而成．该方法所得的传感器位置主要位于动态响应比较大区域，有利于提高信噪比；同时能够有效地保证模态振型的独立性，可以较完整地获得结构模态信息．针对这种组合算法的有效性采用简易机翼模型从数值计算和实验两方面进行了验证

基于归一化应变梯度变化的损伤识别方法研究

针对传统静态损伤识别测量方法存在测量系统布置烦琐、测点有限以及基于应变参量的损伤识别受加载条件限制的问题,一种基于归一化应变梯度变化(Differential Gradient of Normalized Strain,DGNS)的损伤识别方法被提出。通过对只含有矩形槽的试件和同时含有方形通孔和裂纹的试件的数值计算,说明该方法能够有效识别塑性变形、裂纹等损伤。实验中,提出采用应变等值线密度变化(Differential of Strain Contour Density,DSCD)取代DGNS用以识别结构损伤,两者具有相同的物理意义,但DSCD更加有效地保证云图的平滑性和可视性,实验证明DSCD可以有效地识别塑性损伤。研究表明,DGNS(DSCD)可以很好地刻画出结构塑性变形、裂纹损伤特性,剔除由于结构自身不均匀造成的应变集中区域的影响,有效地孤立出损伤区域;DGNS(DSCD)是结构的本征参数,不依赖于外部载荷幅值;相比于传统的应变损伤识别,DGNS(DSCD)具有更加敏感、更早捕捉损伤的优势

双轮式机器人在球面上的运动学分析

为研究球形容器上双轮式机器人的运动控制问题，分析了机器人在球面上的运动特点。在机器人中心点处做切平面和法平面，将三维环境中机器人的运动分解并投影在二维坐标平面内进行运动描述，得到了球面上机器人的运动轨迹及速度，进而建立了机器人在球面上运动的数学模型。对运动学模型进行离散化，并在Matlab中进行仿真。仿真结果验证了模型的可行性，仿真过程的图形直观形象地显示了机器人的运动状态，这为机器人的运动规划提供了理论帮助

海洋平台结构的传感器优化布置研究

针对海洋平台类桁架结构,一种基于遗传算法和Guvan缩减法,采用多层分区思想的传感器优化布置方法被提出。该方法把传感器优化过程等价为结构主自由度的合理选择,通过MATLAB调用ANSYS的方式实现传感器位置的优化计算。在计算中,根据传感器数量和结构主支撑的数目,沿桁架结构纵向合理分区,有效保证传感器位置合理性。研究表明,该方法得到的传感器位置位于动

A damage identification method based on differential gradient of normalized strain

A damage identification method based on differential gradient of normalized strain (DGNS) is presented to overcome the disadvantages of traditional static damage identification, such as the complicacy of measurement system and the limited measurement points etc. Two numerical simulations were conducted on a dog-bone specimen to verify the feasibility of the method. In the experiment, differential of strain contour density (DSCD), which has the same physical meaning with DGNS，significantly improves the smoothness and visualization of field information. Both the simulation and experiment results show that, DGNS (DSCD) is capable of describing the structural damage property meanwhile effectively isolates the damaged areas from regions with inhomogeneous deformation due to geometric inhomogeneity. Moreover, DGNS (DSCD) is a structural intrinsic parameter, and independent on external loads

Application of model reduction technique and structural subsection technique on optimal sensor placement of truss structures

An optimal sensor placement (OSP) method based on structural subsection technique (SST) and model reduction technique was proposed for modal identification of truss structures, which was conducted using genetic algorithm (GA). The constraints of GA variables were determined by SST in advance. Subsequently, according to model reduction technique, the optimal group of master degrees of freedom and the optimal objective function value were obtained using GA in a case of the given number of sensors. Correspondingly, the optimal number of sensors was determined according to optimal objective function values in cases of the different number of sensors. The proposed method was applied on a scaled jacket offshore platform to get its optimal number of sensors and the corresponding optimal sensor layout. Then modal kinetic energy and modal assurance criterion were adopted to evaluate vibration energy and mode independence property. The experiment was also conducted to verify the effectiveness of the selected optimal sensor layout. The results showed that experimental modes agreed reasonably well with numerical results. Moreover the influence of the proposed method using different optimal algorithms and model reduction technique on optimal results was also compared. The results showed that the influence was very little.</p