title: Torsional ultrasonic transducer computational design optimization.
abstract: A torsional piezoelectric ultrasonic sensor design is proposed in this paper and computationally tested and optimized to measure shear stiffness properties of soft tissue. These are correlated with a number of pathologies like tumors, hepatic lesions and others. The reason is that, whereas compressibility is predominantly governed by the fluid phase of the tissue, the shear stiffness is dependent on the stroma micro-architecture, which is directly affected by those pathologies. However, diagnostic tools to quantify them are currently not well developed. The first contribution is a new typology of design adapted to quasifluids. A second contribution is the procedure for design optimization, for which an analytical estimate of the Robust Probability Of Detection, called RPOD, is presented for use as optimality criteria. The RPOD is formulated probabilistically to maximize the probability of detecting the least possible pathology while minimizing the effect of noise. The resulting optimal transducer has a resonance frequency of 28 kHz.
authors.affiliation: Dpt. of Structural Mechanics, University of Granada, Politécnico de Fuentenueva, 18071 Granada, Spain. Electronic address: jmelchor@ugr.es.
authors.forename: J
authors.initials: J
authors.lastname: Melchor
authors.affiliation: Dpt. of Structural Mechanics, University of Granada, Politécnico de Fuentenueva, 18071 Granada, Spain. Electronic address: grus@ugr.es.
authors.forename: G
authors.initials: G
authors.lastname: Rus
mesh_terms: D017076:Computer-Aided Design; D004867:Equipment Design; D020342:Finite Element Analysis; D008962:Models, Theoretical; D012680:Sensitivity and Specificity; D019415:Torque; D014159:Transducers; D014465:Ultrasonics / Q000295:instrumentation*
keywords: Finite element method; Non-destructive evaluation; Probability of detection; Soft tissue mechanics; Torsional ultrasound