Sökning: "Interface cracks"
Visar resultat 1 - 5 av 72 avhandlingar innehållade orden Interface cracks.
1. Modelling and simulation of short fatigue cracks
Sammanfattning : The growth of short fatigue cracks deviates from the behaviour of long fatigue cracks even if subjected to the same nominal driving force. The influence from the microstructure is pronounced, while crack closure effects may not be that important as for longer cracks. LÄS MER
2. Nonlinear Interaction Between Ultrasonic Waves and Cracks and Interfaces
Sammanfattning : The subject of this thesis is the development of new ultrasound inspection techniques for detection of cracks that are smaller than the wavelength of the inspecting wave and the characterization of cracks in fluid-filled pipes as either surface-breaking or subsurface. The spectrum of the scattered field of a partially closed crack comprises harmonic components not expected to be found in the case of linear scatterers such as pores or inclusions. LÄS MER
3. Life Prediction and Mechanical Behavior of Thermal Barrier Coatings
Sammanfattning : Delamination and spallation of thermal barrier coating (TBC) systems, used in hot parts of gas turbines, have been studied with respect to thermal fatigue. TBCs with and without pre-existing cracks were investigated. Thermal shock tests were performed until coating spallation. LÄS MER
4. The role of microstructure for crack propagation in cortical bone
Sammanfattning : Healthy cortical bone tissue is both tough and strong and has a unique ability to resist fracture. One reason is the hierarchical structure of the tissue where toughening mechanisms at all length scales act to slow down or stop a propagating crack. LÄS MER
5. Elastic Wave Propagation in Anisotropic Media. Application to Ultrasonic NDT
Sammanfattning : The subject of this thesis is elastic wave propagation in anisotropic materials with application to ultrasonic nondestructive testing (NDT). The first part of the thesis is concerned with modeling of ultrasonic transducers and wave propagation in anisotropic materials in general. First, a scalar 2-D case is considered. LÄS MER