Main Battle Tank Flexible Gun Tube Disturbance Model: Three-Segment Model

Calculations in stochastic geometry are applied to the geological problem of analysing the statistical distribution of fission tracks in an apatite crystal, when information is available only by plane sampling. The feature of particular interest is the effect of anisotropy, in the sense of dependence of track length on orientation. Using a realistic Poisson line-segment model, we obtain formulae for the density of line segments intersecting an arbitrary plane and for the length distributions of confined tracks, semi-tracks and projected semi-tracks in terms of the conditional distribution of length given orientation. These formulae are used to explain and quantify the effect of anisotropy seen in experimental data from fission track annealing studies. We argue that track orientations, in addition to lengths, carry potentially useful information. For confined tracks, we recommend that both length and angle to the c -axis be measured as routine practice. For projected semi-tracks, where it is much harder to extract useful information from the observed length distribution, the measurement of angle, in addition to length, may prove fruitful, particularly when confined tracks are scarce.

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Shear lag including axial balance of box beams by finite segment model

Journal of Constructional Steel Research ◽

10.1016/j.jcsr.2021.107043 ◽

2021 ◽

pp. 107043

Author(s):

Xiaoyang He ◽

Yiqiang Xiang ◽

Xin Qiu ◽

Zhengyang Chen

Keyword(s):

Shear Lag ◽

Finite Segment ◽

Segment Model ◽

Box Beams

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A quasi-static three-dimensional, mathematical, three-body segment model of the canine knee

Journal of Biomechanics ◽

10.1016/j.jbiomech.2004.02.034 ◽

2004 ◽

Vol 37 (12) ◽

pp. 1849-1859 ◽

Cited By ~ 31

Author(s):

R. Shahar ◽

L. Banks-Sills

Keyword(s):

Three Dimensional ◽

Body Segment ◽

Segment Model ◽

Three Body

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Multiscale modelling of the human lumbar facet capsular ligament: analysing spinal motion from the joint to the neurons

Journal of The Royal Society Interface ◽

10.1098/rsif.2018.0550 ◽

2018 ◽

Vol 15 (148) ◽

pp. 20180550

Author(s):

Vahhab Zarei ◽

Rohit Y. Dhume ◽

Arin M. Ellingson ◽

Victor H. Barocas

Keyword(s):

Axial Rotation ◽

Fe Model ◽

Spinal Motion ◽

Capsular Ligament ◽

Segment Model ◽

Motion Segment ◽

Flexion Extension ◽

Vertebral Kinematics ◽

High Level ◽

Lumbar Facet

Due to its high level of innervation, the lumbar facet capsular ligament (FCL) is suspected to play a role in low back pain (LBP). The nociceptors in the lumbar FCL may experience excessive deformation and generate pain signals. As such, understanding the mechanical behaviour of the FCL, as well as that of its underlying nerves, is critical if one hopes to understand its role in LBP. In this work, we constructed a multiscale structure-based finite-element (FE) model of a lumbar FCL on a spinal motion segment undergoing physiological motions of flexion, extension, ipsilateral and contralateral bending, and ipsilateral axial rotation. Our FE model was created for a generic FCL geometry by morphing a previously imaged FCL anatomy onto an existing generic motion segment model. The fibre organization of the FCL in our models was subject-specific based on previous analysis of six dissected specimens. The fibre structures from those specimens were mapped onto the FCL geometry on the motion segment. A motion segment model was used to determine vertebral kinematics under specified spinal loading conditions, providing boundary conditions for the FCL-only multiscale FE model. The solution of the FE model then provided detailed stress and strain fields within the tissue. Lastly, we used this computed strain field and our previous studies of deformation of nerves embedded in fibrous networks during simple deformations (e.g. uniaxial stretch, shear) to estimate the nerve deformation based on the local tissue strain and fibre alignment. Our results show that extension and ipsilateral bending result in largest strains of the lumbar FCL, while contralateral bending and flexion experience lowest strain values. Similar to strain trends, we calculated that the stretch of the microtubules of the nerves, as well as the forces exerted on the nerves' membrane are maximal for extension and ipsilateral bending, but the location within the FCL of peak microtubule stretch differed from that of peak membrane force.

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