| ABSTRACT: | MODEL OF ULTRASONIC RAY PATHS IN AN ANISOTROPIC WELD BASED ON RAY
METHOD
H.Wirdelius, Q.Liu
Chalmers Lindholmen University College, Gothenburg, Sweden.
Experiences from isotropic materials suggest that it is impossible to derive a statistical model with few
parameters to model a weld in an anisotropic material. The parameter that remains unknown even after a
large number of empirical investigations is the orientation of the dendrites due to the heating. Our intention
is to apply some simplified models in an optimization scheme so as to predict the dendrites' orientation in
different welds. In this paper, a model of ultrasonic ray paths through an anisotropic weld, as well as the
corresponding computer simulation, is presented. First, based on the previous work on texture analysis of
various austenitic stainless steel weld samples, a number of simplified models of the geometry of welds are
established. They are subdivided into a finite number of smaller regions with specified anisotropy. Then by
means of the ray tracing method, ray paths running through these models are developed for different cases.
As a function of incident angle, the point of entrance of the sound path to the weld and the given orientation
of the dendrites, the model gives the point where the sound leaves the weld, the time of flight and the angle
between the sound ray and the weld. A number of numerical simulations of the direct problem are also
provided as a validation of the model.
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