Modelling of a Cervical Plate and Human Cervical Section C3 – C5 under Compression Loading Conditions Using the Finite Element Method

This paper presents the modelling of the effects due to load conditions on the cervical section defined between C3 and C5 after a cervical plate implant is used to transfer the compression loads from C3 to C5 as C4 is considered to be damaged as a result of a medical condition. For this study, three different scenarios which describe the common motion condition of the head-neck system are modelled. The first one refers to the effect of the head weight over the considered section. In the second case the average patient weight is supported by C3 and C5 vertebrae. The last case simulates extreme loading conditions as vertebrae lesions occur when these are compressed beyond its failure limit; the ultimate stress to compression load failure value is applied to C3. The stability and mechanical behaviour of cervical plates under compression loading conditions is evaluated using the Finite Element Method (FEM). Cervical plates are useful to restore stability of the spine by improving the inter-vertebral fusion, particularly when the cervical body has been damaged. The results show that the stresses on the plate and fixation screws, for the three cases, are within the elastic range. Conversely, it has to be considered that cortical and trabecular bone densities vary from one patient to another due to a number of factors, which can influence the fixation conditions of the screws. In the case of this analysis, healthy bone conditions were considered and the obtained results show that the risk of the integrity of the screwimplant- vertebrae system is not compromised.

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Behavior of Square Hollow Section Steel Tubes Filled with Concrete under Different Loading Conditions

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.577.1097 ◽

2014 ◽

Vol 577 ◽

pp. 1097-1103

Author(s):

Tian De Jin ◽

Lan Hui Guo

Keyword(s):

Finite Element Method ◽

Finite Element ◽

Yield Strength ◽

Bearing Capacity ◽

Area Ratio ◽

Loading Conditions ◽

The Finite Element Method ◽

Hollow Section ◽

Core Concrete ◽

Element Method

In this paper, the behavior of composite stub columns under different loading conditions is studied using the finite element method. The accuracy of the theoretical method is validated by comparing with the experimental results. The behavior of specimen under different loading conditions is analyzed. Then, based on the finite element method, the comparison of mechanical behavior under three typical loading conditions is studied. The results show that the difference on bearing capacity will become larger with the increase of steel area to concrete area ratio. For the core concrete loaded specimen with lower steel area-to-concrete area ratio, whose bearing capacity is the lowest, but its ductility is very good. With the increase of the steel yield strength, the bearing capacity will increase evidently for specimen loaded simultaneously. While for the specimen with only core concrete loaded, the steel yield strength has little influence except increase of ductility.

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Internal ballistics of polygonal and grooved barrels: A comparative study

Science Progress ◽

10.1177/00368504211016954 ◽

2021 ◽

Vol 104 (2) ◽

pp. 003685042110169

Author(s):

Usiel S Silva-Rivera ◽

Luis Adrian Zúñiga-Avilés ◽

Adriana H Vilchis-González ◽

Pedro A Tamayo-Meza ◽

Wilbert David Wong-Angel

Keyword(s):

Finite Element Method ◽

Finite Element ◽

Comparative Study ◽

Experimental Tests ◽

Loading Conditions ◽

The Finite Element Method ◽

Maximum Deformation ◽

Internal Ballistics ◽

Internal Deformation ◽

Element Method

As a parameter important ballistic, the research about polygonal and grooved barrels’ behavior has not been widely carried out. The pressures, velocities, stresses, deformations, and strains generated by the firing of 9 mm × 19 mm ammunition in weapons with polygonal barrels are analyzed numerically and experimentally, compared with those generated in pistols with grooved barrels. The Finite Element Method with equal boundary and loading conditions was used in both types of guns, specifying the actual materials of the projectile and the barrels. Subsequently, experimental tests were carried out on various weapons with 9 mm ammunitions of 115, 122, and 124 gr. The results show that the 9 mm bullet fired in a polygonal barrel undergoes a maximum deformation towards its exterior of 0.178 mm and interior of 0.158 mm, with stress up to 295.85 MPa. Compared with 0.025 mm maximum external deformation and 0.112 mm internal deformation of 9 mm projectiles fired in a grooved barrel, with stress up to 269.79 MPa. The deformation in the polygonal barrel is in a greater area, but the rifling impression left is less deep, making its identification more difficult. Although there are differences in the stresses and strains obtained, similar velocity and pressure parameters are achieved in the two types of barrels. This has application in the development and standardization of new kinds of barrels and weapons.

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Biomechanical Modeling of Options for Internal Fixation of Unilateral Fractures of the Sacrum

Traumatology and Orthopedics of Russia ◽

10.21823/2311-2905-2020-26-2-79-90 ◽

2020 ◽

Vol 26 (2) ◽

pp. 79-90

Author(s):

I. V. Kazhanov ◽

S. I. Mikityuk ◽

А. V. Dol’ ◽

D. V. Ivanov ◽

А. V. Kharlamov ◽

...

Keyword(s):

Finite Element Method ◽

Finite Element ◽

Internal Fixation ◽

The Finite Element Method ◽

Equivalent Stresses ◽

Compression Load ◽

Sacroiliac Screw ◽

Sacral Fractures ◽

Sacroiliac Screws ◽

Element Method

Relevance. Currently, the stability of various options for the fixation of sacral fractures by the finite element method has not been sufficiently studied.Purpose — the biomechanical characteristics of two variants of internal fixation of unilateral sacral fractures by various implants and the localization of the line of its fracture with respect to the articular facet of the L5-S1 vertebrae were studied.Materials and Methods. Using the finite element method, we studied the biomechanical characteristics of two options for fixing a one-sided longitudinal fracture of the sacrum with different localization of the line of its fracture: outside, inside and directly on the joint facet L5-S1. Two fixation options are considered: cannulated sacroiliac screws and a similar option in combination with a bilateral lumbar-pelvic transpedicular system.Results. The stresses in implants and bone under compression load and torso forward or backward are almost the same in all models. In the model of fixation with a sacroiliac screw of a one-sided longitudinal sacral fracture, the line of which passes through the articular process S1 of the vertebra (Isler II type), the greatest stress in the screws under compression load and bending moment was 619.7 MPa, which exceeds the yield strength of the titanium alloy and can damage the implants. In all models where the transpedicular system additionally acted as fixing structures, a decrease of 42–77% of maximum displacements was noted, by 28–79% of equivalent stresses in implants under all types of loads, while the equivalent stresses in the bone structures did not differ significantly. In models where the transpedicular system was additionally applied, a decrease of 42–77% of maximum displacements was noted, by 28-79% of stresses in implants under all types of loads, while the stresses in the bones did not differ much.Conclusion. In all cases of localization of the line of unilateral fracture of the sacrum, the use of a transpedicular system in combination with sacroiliac screws is more stable from the point of view of biomechanics. The most unstable is a one-sided longitudinal fracture of the sacrum passing through the facet L5-S1.

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Simulation of tuning graphene plasmonic behaviors by ferroelectric domains for self-driven infrared photodetector applications

Nanoscale ◽

10.1039/c9nr06508c ◽

2019 ◽

Vol 11 (43) ◽

pp. 20868-20875 ◽

Cited By ~ 1

Author(s):

Junxiong Guo ◽

Yu Liu ◽

Yuan Lin ◽

Yu Tian ◽

Jinxing Zhang ◽

...

Keyword(s):

Finite Element Method ◽

Finite Element ◽

Interfacial Effect ◽

Infrared Photodetector ◽

The Finite Element Method ◽

Ferroelectric Domains ◽

Element Method

We propose a graphene plasmonic infrared photodetector tuned by ferroelectric domains and investigate the interfacial effect using the finite element method.

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