Semi-analytical finite-element modeling approach for guided wave assessment of mechanical degradation in bones

Abstract

Numerical models based on the Semi Analytical Finite-Element method are used to study the characteristics of guided wave modes supported by bone-like multi-layered tubular structures. The method is first validated using previous literature and experimental studies on phantoms mimicking healthy and osteoporotic conditions of cortical bone, and later used to study a trilayer marrow-bone-tissue system at varying mechanical degradation levels. The results show that bone condition strongly affects the modal properties of axially propagating guided waves and indicates that L(0,3) and F(1,6) are suitable modes for assessing the mechanical condition of the bone. The work here reports suitable modal selection and their dispersion properties which would the aid in development of a transduction mechanism for mechanical assessment of bones.

Notes on osculations and mode tracing in semi-analytical waveguide modeling

“…In addition, we wish to restrict the discussion to Hermitian eigenvalue problems. There are several closely related methods to achieve this goal, in particular, the thin layer method (TLM) [21][22][23], scaled boundary finite element method (SBFEM) [24][25][26] and semi-analytical finite element method (SAFE) [27][28][29]. For the simple application discussed here where only systems of a constant cross-section in the frequency domain are addressed, these methods can be considered to be equivalent.…”

Effect of intracortical bone properties on the phase velocity and cut-off frequency of low-frequency guided wave modes (20–85 kHz)

“…The SAFE method has recently been used to simulate the modal properties of the ultrasonic guided wave in bone systems (Nguyen and Naili, 2014;Nguyen et al, 2017;Thakare et al, 2017;Tran et al, 2015). The computation of the time response from the modal properties of waveguides in an infinite arbitrary cross-section waveguide was previously described by Wilcox et al (Wilcox et al, 2001) and Loveday (Loveday, 2008).…”

Novel hermetically sealed device to realize unconventional phonon blockade at near-micron dimensions and milliKelvin temperatures

“…Phonons refer to quantized states of vibration (in analogy to photons that similarly quantify light) which underlies all elastic wave phenomena [1,2]. Today elastic waves are vital to a range of applications for sensing, imaging and diagnostics in engineering and biomedicine [3][4][5]. Due to the generally slower propagation velocities involved, elastic wave approaches for diagnostics suffer from much poorer resolution as compared what is achievable using electromagnetics.…”