Search for dissertations about: "ultrasonic testing"

Showing result 1 - 5 of 44 swedish dissertations containing the words ultrasonic testing.

2. 1. Non-destructive measurement of near-surface cracks in railheads : with focus on ultrasonic inspections

   Author : Rayendra Anandika; Jan Lundberg; Paul Wilcox; Luleå tekniska universitet; []
   Keywords : ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; rail inspection; phased array; ultrasonic testing; eddy current testing; surface cracks; non-destructive testing; NDT; railway; condition monitoring; Drift och underhållsteknik; Operation and Maintenance;

   Abstract : Near-surface cracks in railhead that caused by rolling contact fatigue (RCF) is one of a kind rail defects that degrade rail track quality. Dependent on the trail load, the cracks can reach to severe level quickly. READ MORE

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

   Author : Tomas Olofsson; Uppsala universitet; []
   Keywords : ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; 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;

   Abstract : 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. READ MORE

5. 3. Very high cycle fatigue of automotive steels : Testing and computation at 20 kHz

   Author : Mohamed Sadek; Jens Bergström; Nils Hallbäck; Ulrich Krupp; Karlstads universitet; []
   Keywords : ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; Very high cycle fatigue; ultrasonic fatigue testing; automotive steels; fatigue strength; stress intensity computation; crack growth; Materialteknik; Materials Engineering;

   Abstract : Mechanical fatigue failure occurs in components subjected to cyclic loading. A crack initiates at critical regions in the component and propagates during repeated loading. The expected fatigue life depends on the level, type and frequency of the loading. READ MORE

6. 4. On the modelling of ultrasonic testing using boundary integral equation methods

   Author : Jonathan Westlund; Chalmers University of Technology; []
   Keywords : Boundary element method; Regularization; Ultrasonics; Boundary integral equation method; T matrix.; Elastic waves; Nondestructive testing; Scattering;

   Abstract : Ultrasonic nondestructive testing has important applications in, for example, the nuclearpower and aerospace industries, where it is used to inspect safety-critical parts for flaws.For safe and reliable testing, mathematical models of the ultrasonic measurement systemsare invaluable tools. READ MORE

7. 5. Modelling of ultrasonic testing for cracks near a non-planar surface

   Author : Jonathan Westlund; Chalmers University of Technology; []
   Keywords : Ultrasonics; BIEM; Elastic waves; Nondestructive testing; Crack; BEM.;

   Abstract : Nondestructive testing using ultrasound has important applications in e.g. the nuclear power and aerospace industries, where it is used to inspect safety-critical parts for flaws. READ MORE