软基水闸闸基脱空区域识别研究

发布时间：2018-06-19 12:11

本文选题：损伤识别 + 模型修正　；参考：《南昌大学》2016年硕士论文

【摘要】：在运行过程中,水闸闸基受到水流作用,容易出现脱空现象,进而导致不均匀沉陷、泥沙淘空等病害,建在软基或砂基上的水闸,闸基脱空现象更为明显。同时,由于位于水下的闸基脱空现象在安全检查中难以发现,安全隐患不易及时被发现。因此,研究有效的软基水闸闸基脱空区域检测方法对于保障水工结构的安全运行具有十分重要的意义和价值。本文的具体研究内容如下:(1)参考工程资料,利用ANSYS建立壳体单元水闸模型,将软基水闸闸基脱空区域进行参数化描述。通过分析不同脱空形式下水闸结构振动特征,提出振动模式分类方法,针对每一类振动模式建立脱空参数与结构模态参数之间的高精度响应面方程。对比响应面模型的计算值与实测结构模态(数值模拟),调整闸基脱空参数,使得响应面模型的计算值与实测值尽量接近,修正后的脱空参数即可指示水闸闸基脱空区域。基于壳体单元模型的研究分析,验证了闸基脱空区域识别方法的可行性。(2)为了更加符合实际工程,建立实体单元水闸有限元模型,相比于壳体模型,实体模型的结构动力特性更加符合实际。基于ANSYS的结构模态分析,建立结构固有频率、振型与闸基脱空参数之间的响应面方程,利用模态信息构建目标函数,基于遗传算法对实体单元水闸闸基脱空区域进行识别研究。(3)为了提高识别算法的鲁棒性,提出了基于位移统计矩的水闸闸基脱空区域识别方法。利用ANSYS有限元软件对水闸模型进行时程计算分析,提取响应信息,计算位移统计矩,建立统计矩特征参数与脱空参数之间的函数关系,进而利用实测值(数值模拟)与计算值构建目标函数,通过求解优化问题反演水闸闸基脱空参数。数值模拟分析表明,基于模态信息的水闸闸基脱空区域识别方法,能很好的指示闸基脱空区域,且随着噪声级别的提高,识别结果会逐渐变差。与之相比,基于统计矩的水闸闸基脱空区域识别方法具有较好的鲁棒性,在噪声级别较大的情况下,识别结果依然能够较好的指示脱空区域。
[Abstract]:In the course of operation, the sluice foundation is affected by the flow of water, and it is easy to appear the phenomenon of void, which leads to uneven subsidence, sediment scouring and other diseases. The sluice built on the soft foundation or sand foundation is more obvious. At the same time, it is difficult to find the hidden danger in safety inspection because of the phenomenon of underwater sluice base clearance. Therefore, it is of great significance and value to study the effective detection method for the clearance area of the soft foundation sluice for ensuring the safe operation of the hydraulic structure. The concrete research contents of this paper are as follows: (1) with reference to engineering data, the shell element sluice model is established by ANSYS, and the void area of soft foundation sluice is parameterized. By analyzing the vibration characteristics of sluice structures in different emptying forms, a vibration mode classification method is proposed, and a high-precision response surface equation between the emptying parameters and the structural modal parameters is established for each type of vibration mode. Comparing the calculated value of response surface model with the measured structural modal (numerical simulation, adjusting the parameters of sluice foundation emptying, the calculated value of response surface model is as close as possible to the measured value, and the modified emptying parameter can indicate the sluice foundation void area. Based on the research and analysis of shell element model, the feasibility of identification method of sluice foundation clearance area is verified. In order to more accord with the actual engineering, the finite element model of sluice with solid element is established, which is compared with the shell model. The structural dynamic characteristics of the solid model are more in line with the reality. Based on the structural modal analysis of ANSYS, the response surface equations between the natural frequency, the mode shape and the clearance parameters of the gate foundation are established, and the objective function is constructed by using the modal information. In order to improve the robustness of the identification algorithm, a new method based on displacement statistical moments is proposed to identify the sluice foundation void area. The finite element software ANSYS is used to analyze the time history of sluice model, to extract the response information, to calculate the statistical moment of displacement, and to establish the functional relationship between the characteristic parameters of statistical moment and the empty parameter. Then the objective function is constructed by using the measured value (numerical simulation) and the calculated value, and the parameters of sluice foundation clearance are inversed by solving the optimization problem. Numerical simulation results show that the identification method based on modal information can well indicate the gap area of sluice base, and with the increase of noise level, the recognition result will become worse. Compared with this method, the method based on statistical moments has better robustness, and the recognition result can still indicate the void area better when the noise level is large.
【学位授予单位】：南昌大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TV66;TV223

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