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作者 Sharma, Sarit
書名 Application of finite element models to eddy current probe design for aircraft inspection
國際標準書號 0591950111
book jacket
說明 94 p
附註 Source: Dissertation Abstracts International, Volume: 59-07, Section: B, page: 3623
Major Professor: Lalita Udpa
Thesis (Ph.D.)--Iowa State University, 1998
Eddy current nondestructive testing (NDT) methods are used extensively in the inspection of aircraft structures. Improvements and innovations in probe design are constantly required for detection of flaws in complex multilayer aircraft structures. This thesis investigates alternate designs of eddy current probes for addressing some of these problems
An important aspect of probe design is the capability to simulate probe performance. Numerical computation and visualization of the electromagnetic fields can provide valuable insight into the design of new probes. Finite element methods have been used in this dissertation to numerically compute the electromagnetic fields associated with the probe coils, and the eddy current probe signals. A major contribution of this thesis is development of techniques to reduce the computer resource requirement in the finite element modeling: of the eddy current phenomenon
The first flaw detection problem is addressed by focusing the flux of the probe using active compensation techniques. A novel eddy current probe using a combination of coils is proposed and studied using: the 3D model simulation. The probe consists of two current carrying concentric coils to detect flaws closer to the sample edges
Detection of defects in second and third layer of samples has been demonstrated using: the remote field eddy current (RFEC) method. In the RFEC method the pickup coils are located in the far field region which leads to a large volume to be modeled numerically with large number of elements. A method involving partitioning the volume in the 3D finite element model is demonstrated for the RFEC detection of defects
Magneto-optic/eddy current imaging (MOI) techniques have shown considerable promise in the detection of corrosion in the second layer. MOI is a nondestructive testing method currently in use in aircraft frame inspection and it involves optically sensing the magnetic field induced by the eddy currents in the test sample. A numerical model for simulating the MOI test geometry has been developed as an aid for tool optimization
In the modeling work, effort is focused towards reducing the computation time and utilize larger computer memory the programs that solve the linear equations obtained in the finite element method have been parallelized using the message passing interface (MPI) to run on a cluster of computers
School code: 0097
DDC
Host Item Dissertation Abstracts International 59-07B
主題 Engineering, Electronics and Electrical
Engineering, Aerospace
0544
0538
Alt Author Iowa State University
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