Sökning: "Ultrasonic pulse-echo testing"

Hittade 4 avhandlingar innehållade orden Ultrasonic pulse-echo testing.

  1. 1. Maximum a posteriori deconvulution of ultrasonic data with applications in nondestructive testing : Multiple transducer and robustness is

    Författare :Tomas Olofsson; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Materials science; Ultrasonic pulse-echo testing; nondestructive testing; maximum a posteriori estimation; linear minimum mean squared error estimation; robust filtering; multivariable filtering; sparse deconvolution; Materialvetenskap; Materials science; Teknisk materialvetenskap; Signal Processing; signalbehandling;

    Sammanfattning : In the thesis, various aspects of deconvolution of ultrasonic pulse-echo signals in nondestructive testing are treated. The deconvolution problem is formulated as estimation of a reflection sequence which is the impulse characteristic of the inspected object and the estimation is performed using either maximum a posteriori (MAP) or linear minimum mean square error (MMSE) estimators. LÄS MER

  3. 2. Modelling crack-induced ultrasonic scattering in a thick-walled pipe

    Författare :Jacob Rubenson; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Cylindrical pipes; Non-Destructive Testing; Crack; Ultrasonic waves; Hypersingular integral method;

    Sammanfattning : Ultrasonic testing is used in several industries where there are high demands on safety, e.g. nuclear power and aerospace industries. In the nuclear industry and elsewhere there are many pipes that need to be tested. LÄS MER

  4. 3. Ultrasonic NDT in Defect Detection - Mathematical modelling

    Författare :Håkan Wirdelius; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; crack; null field approach; transducers; optimisation; ultrasonics; elastic waves; nondestructive testing; T matrix method; inverse problem;

    Sammanfattning : This thesis is concerned with the mathematical modelling of the ultrasonic nondestructive testing situation. The first part of the thesis treats a simplified model of an ultrasonic transducer and its implementation into a T-matrix method-based solution to a crack scattering problem. LÄS MER

  5. 4. Optimal Detectors for Transient Signal Families and Nonlinear Sensors : Derivations and Applications

    Författare :Daniel Asraf; Mats Gustafsson; Anders Grennberg; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Signalbehandling; optimal detection; transient signals; noncoherent detection; unknown arrival time; ultrasonic nondestructive testing; nonlinear sensor; stochastic resonance; Signalbehandling; Signal processing; Signalbehandling; Signal Processing; signalbehandling;

    Sammanfattning : This thesis is concerned with detection of transient signal families and detectors in nonlinear static sensor systems. The detection problems are treated within the framework of likelihood ratio based binary hypothesis testing. LÄS MER