UTSim2 validation

The Center for NDE (CNDE) at Iowa State University has a long history of developing physics models for NDE and packaging these models into simulation tools which make the modeling capabilities accessible to CNDEs industrial sponsors. Recent work at CNDE has led to the development of a new ultrasonic simulation package, UTSim2, which aims to continue this tradition of supporting industrial application of CNDE models. In order to meet this goal, UTSim2 has been designed as an extensible software package which can support previously-developed physics models as well as future models yet to be developed. Initial work has focused on the implementation of a Gauss-Hermite beam model, a paraxial approximation, which is implemented as part of the Thompson-Gray measurement model. This paper will present recent validation results and include comparisons against both previously-validated model output and newly-performed experiments

Surrogate modeling of ultrasonic simulations using data-driven methods

Ultrasonic testing (UT) is used to detect internal flaws in materials and to characterize material properties. In many applications, computational simulations are an important part of the inspection-design and analysis processes. Having fast surrogate models for UT simulations is key for enabling efficient inverse analysis and model-assisted probability of detection (MAPOD). In many cases, it is impractical to perform the aforementioned tasks in a timely manner using current simulation models directly. Fast surrogate models can make these processes computationally tractable. This paper presents investigations of using surrogate modeling techniques to create fast approximate models of UT simulator responses. In particular, we propose to integrate data-driven methods (here, kriging interpolation with variable-fidelity models to construct an accurate and fast surrogate model. These techniques are investigated using test cases involving UT simulations of solid components immersed in a water bath during the inspection process. We will apply the full ultrasonic solver and the surrogate model to the detection and characterization of the flaw. The methods will be compared in terms of quality of the responses

Evaluation of the fidelity of feature descriptor-based specimen tracking for automatic NDE data integration

This research addresses inspection location tracking in the field of nondestructive evaluation (NDE) using a computer vision technique to determine the position and orientation of typical NDE equipment in a test setup. The objective is the tracking accuracy for typical NDE equipment to facilitate automatic NDE data integration. Since the employed tracking technique relies on surface curvatures of an object of interest, the accuracy can be only experimentally determined. We work with flash-thermography and conducted an experiment in which we tracked a specimen and a thermography flash hood, measured the spatial relation between both, and used the relation as input to map thermography data onto a 3D model of the specimen. The results indicate an appropriate accuracy, however, unveiled calibration challenges

Anxiety and impulsivity: Factors associated with premature graying in young dogs

AbstractThe present study examined the association of anxiety and impulsivity with premature muzzle grayness among young dogs. A sample of 400 dogs, ages 1–4 years was obtained at dog parks, shows, veterinary clinics, and other venues. Each dog was photographed and the degree of muzzle grayness was rated on an ordinal scale ranging from “no gray” to “full gray.” White or pale colored dogs were dropped from the study because it was impossible to determine degree of grayness. Each owner filled out a questionnaire assessing the constructs of anxiety and impulsivity, as well as other behaviors and characteristics. To prevent response bias, owners were told that the purpose of the study involved dog lifestyle. Distractor items were added to the survey to prevent the owner from guessing the purpose of the survey. Examples of survey items indicating anxiety included: destruction when left alone; hair loss on vet exam or being in a new place; and cringes/cowers in response to groups of people. Examples of survey items indicating impulsivity included: jumping on people, inability to calm, loss of focus, hyperactivity after exercise. In our sample of young dogs, latent variable regression showed that the extent of muzzle grayness was significantly and positively predicted by anxiety (p=0.005) and impulsivity (p<0.001). Dog size, spay/neuter status, or medical problems did not predict extent of muzzle grayness. Fear responses to loud noise, unfamiliar animals and people were associated with increased grayness. Ordinal regression analysis showed that muzzle grayness was significantly predicted by fear of loud noises (p=0.001), unfamiliar animals (p=0.031), and unfamiliar people (p<0.001). Premature graying in young dogs may be a possible indicator of anxiety, fear or impulsivity issues in dogs under four years of age