Finite element aided measurement of stress fields in different bone layers subject to therapeutic ultrasonic excitation

Pan, Wenlei; Shen, Yi; Liu, Ting; Yu, Renlong; Fu, Ping

doi:10.1109/i2mtc.2014.6860714

Cited by 1 publication

(5 citation statements)

References 16 publications

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“…Instead of directly exciting on the bone surface [8]- [10], [31], the probe was placed on skin and acoustic wave propagates from soft tissue to bone. Stress and strain are 3-D and may build up in any direction within bone.…”

Section: Resultsmentioning

confidence: 99%

“…The first step is to discretize domain of interest into adequate numbers of elements with dimensions small enough [8], [18]. Some items need to be considered in the discretization.…”

Section: B Finite Element Numerical Computationmentioning

confidence: 99%

“…Here, it is used as an energy-direct approach [23] for a time-domain solution to the homogeneous elastic wave equation (8). For dynamic system, the energy functional [24] we introduced into the bone tissue is…”

Section: Elastic Wave Propagation In Bonementioning

confidence: 99%

“…In the finite element model of this paper, the skeletal muscle is modeled as an elastomer, of which the elasticity is linear when very small strain occurs [8]. The material properties of different tissues involved in the model are shown in Table I.…”

Section: Modeling Of Bone and Soft Tissuementioning

confidence: 99%

“…However, the measurement of ultrasound parameters like maximum value, threshold, and zero crossing [7] in bone is not precise enough and can be easily disturbed by instrumentation noise. Finite element method (FEM) [8], [9], [18]- [29] is good at processing large mechanics and acoustics datasets, and can be used as a helper method to experimental measurement, such as the quantitative measurement of ultrasound reflection, backscattering, and guided-wave propagation [10]- [11], [31]. FEM has also been clearly demonstrated that it is a good virtual measurement tool for physiological parameters determination [14]- [17], bone structures reconstruction [12], [13], and tissue strain-stress analyzation [14].…”

mentioning

confidence: 99%

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Stress Estimation in Different Bone Layers Subject to Therapeutic Ultrasound in an Intelligent Bone System

Pan

Shen

Liu

et al. 2015

IEEE Trans. Instrum. Meas.

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Physiological effects caused by power ultrasound radiation are of therapeutic benefits for fracture healing. However, these effects are hard to detect with current instrumentations. The aim of this paper is to analyze the behavior of bone subject to therapeutic ultrasound and provide data reference for an intelligent bone ultrasonic system. In this paper, we adopted a 3-D finite element method as a virtual measurement tool to study the acoustic-radiation-induced stress fields inside and on the surface of bone. The equivalent long bone model was built and the soft tissue was involved by establishing coupling connections with bone surface points. The ultrasound radiation was generated by a 2-MHz excitation and was applied on the surface of soft tissue. In this paper, we first defined six paths in different bone layers to quantitatively study the longitudinal stress distribution and examined the concentration center positions and width with sliding windows. Then, the circumferential stress evolution from relaxation fields to concentration fields was investigated by computing the stress fields on cross sections. Analytical dispersion curves were measured to characterize the guided wave modes. The results show that the middle bone tissue has a higher mean stress (2027.7 Pa) than the surface (763.3 Pa) and the outer bone layer (1898.1 Pa), and the stress distribution of the middle layer is less disturbed (coefficient of variation = 39.8%). Also, on cross section of the concentration zones, periodical fields with a distance of half-wavelength are obtained. From 0.2 to 2 MHz, the acoustic intensity grows proportionally with excitation amplitude.Index Terms-Bone, finite element method (FEM), intelligent system, stress field, therapeutic ultrasound.

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Section: Resultsmentioning

confidence: 99%

“…The first step is to discretize domain of interest into adequate numbers of elements with dimensions small enough [8], [18]. Some items need to be considered in the discretization.…”

Section: B Finite Element Numerical Computationmentioning

confidence: 99%