Low-velocity impact positioning method for composite grid structure
A grid structure, low-velocity impact technology, applied in the direction of positioning, measuring devices, instruments, etc., can solve the problems that the grid structure skin damage cannot be detected, the AGS skin damage cannot be detected, and it is difficult to be widely used.
Inactive Publication Date: 2016-05-18
NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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日本东京大学的N.Takeda等人(TakeyaH,OzakiT,TakedaN.StructuralhealthmonitoringofadvancedgridstructureusingmultipointFBGsensors[C] / / SmartStructuresandMaterials2005.ProcofSPIE:Vol.5762.2005:204-211.)(AmanoM,TakahashiI,OkabeY,etal.Identificationofdamagelocationinadvancedgridstructuresusingfiberbragggratingsensor[C] / / SmartStructuresandMaterials2005.ProcofSPIE:Vol.5765,2005:644-655.) First, the research on the health detection of the grille structure of the aircraft rudder was carried out. By comparing the strain difference before and after the damage, the cracking of the ribs and the relationship between the ribs and the skin were successfully detected. delamination; but this method is only effective in the analysis of relatively serious structural damage; Chen Zhenying et al. from Nanjing University of Aeronautics and Astronautics ("Research on Damage Location of Advanced Composite Grid Stiffened Structure (AGS), Master's Thesis, Nanjing Aeronautics and Astronautics University of Aeronautics and Astronautics, 2011) applied the modal curvature method to successfully detect the rib debonding and fracture damage of the composite grid structure, but this method cannot detect the skin damage of the grid structure; Lan Youze et al. ("Research on Damage Detection of Composite Grid Structure Based on Frequency Response Function", master's degree thesis, Nanjing University of Aeronautics and Astronautics, 2013) Aiming at the shortcomings of traditional modal strain energy that cannot detect AGS skin damage, a structure frequency based method is proposed. The damage detection method of the imaginary part of the response function, but this method is very susceptible to the influence of environmental noise, so it is difficult to be widely used in engineering
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[0084] 1. Impact positioning
[0085] In a broad sense, the impact process belongs to the phenomenon of acoustic emission. According to the time difference positioning method, if the piezoelectric sensors are regularly arranged on the surface of the component (the present invention adopts four sensors to realize the identification of the impact source), and the sensing signals are properly processed, the time difference of the signals received by the sensors is measured. It can be converted to get the source of acoustic emission, that is, the impact position, such as figure 1 shown. Suppose the coordinates of the shock source I are (x I ,y I ), the propagation velocity of the Lamb wave induced by the shock is Vg, and the time to reach each sensor is t i , then the location of the shock source can be obtained by solving the following equations:
[0086] ( x...
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The invention discloses a low-speed impact locating method for a composite material cell structure, and belongs to the field of composite material structure engineering structure health monitoring. According to the method, an unconstrained optimization algorithm based on a Newton method is applied to solving the low-speed impact recognition problem of the composite material cell structure, and the low-speed impact fast recognition of the structure is achieved. Based on a sensor array technology, impact induction is applied to the structure to generate Lamb wave signals, and impact response signals of the composite material cell structure are collected. A certain sensor is used as the criterion, the wavelet analysis means is adopted, and the time differences of Lamb waves reaching the other sensors are extracted. The unconstrained optimization algorithm based on the Newton method is adopted to solve and locate a system of nonlinear equations, and therefore the position of an impact source is obtained. The impact source of the composite material cell structure can be recognized fast and effectively, recognition precision is high, and good engineering application value is achieved.
Description
Technical field: [0001] The invention relates to a low-velocity impact positioning method for a composite material grid structure, which belongs to the field of health monitoring of composite material structure engineering structures. Background technique: [0002] The grid structure is composed of reinforcing ribs and skin, and the reinforcing ribs are distributed in a regular polygonal grid, and the structure exhibits anisotropy. As soon as the grid structure came out, it has attracted great attention in the aerospace field due to its advantages of topology optimization, good corrosion resistance, good damage and diffusion resistance, and good designability. In order to meet the requirements of lightweight aerospace vehicles, the composite grid structure (AGS) appeared. Composite materials have high specific strength, specific modulus and corrosion resistance, so more and more scholars apply composite materials to grid structures, and gradually promote their application i...
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IPC IPC(8): G01S5/22
CPCG01S5/20G01S5/22
Inventor徐志伟江艳刘宇周本昊
OwnerNANJING UNIV OF AERONAUTICS & ASTRONAUTICS