scholarly journals Load bearing analysis on Lumbosacral Disc in Pre-operative and Post-operative Thoracic Scoliosis Patient

2021 ◽  
Vol 1 (1) ◽  
pp. 18-29
Author(s):  
Mohankumar Palaniswamy ◽  
Anis Suhaila Shuib ◽  
Shajan Koshy
Keyword(s):  
Intervertebral Disc ◽  
Musculoskeletal Disorder ◽  
Spinal Instrumentation ◽  
Element Model ◽  
Scoliosis Patient ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Thoracic Scoliosis ◽  
Before And After ◽  
Biomechanical Changes

Scoliosis is a musculoskeletal disorder seen all around the world. It affects both the alignment of the vertebra and intervertebral disc. Scoliosis can be treated conservatively with a cast and brace or surgically with spinal instrumentation. During planning for surgical instrumentation, several factors need to be considered. Among those, biomechanical changes in the non-scoliotic vertebrae and discs are important. This is vital in determining the future degenerative changes of the spine. For this reason, this study was conducted with a finite element model of the lumbosacral joint using CT scan files to find the total deformation and equivalent static strain of the lumbosacral disc between pre and post-operative thoracic scoliosis patient. From the results, it is evident that there is a biomechanical change in the lumbosacral disc and structural change in the vertebral alignment followed immediately after corrective surgery. The correction in the alignment of the scoliotic spine brings changes to the biomechanical functionality and load-bearing capacity of the lumbosacral intervertebral disc before and after surgery.

Experimentally Validated Computational Simulation of Lumbar Spine Intervertebral Disc Puncture

2011 ◽  
Author(s):  
Kristen E. Lipscomb ◽  
Nesrin Sarigul-Klijn
Keyword(s):  
Back Pain ◽  
Lumbar Spine ◽  
Intervertebral Disc ◽  
Nucleus Pulposus ◽  
Chronic Back Pain ◽  
Medical Condition ◽  
Computational Simulation ◽  
Element Model ◽  
Before And After ◽  
Spine Model

Back pain is a debilitating medical condition, often with an unclear source. Over time, back pain can affect the work and lifestyle of an individual by reducing job productivity and time spent on enjoyable activities. Discography of the intervertebral disc (IVD) is often used to diagnose pathology of the disc and determine if it may be a source for chronic back pain. It has recently been suggested that discography may lead to IVD degeneration, and has been a cause of controversy among spine care physicians. Using the results from a cadaveric experimental model, a finite element model was first validated. Then, a study was conducted to better understand the changes caused by discography on human spine mechanics. An anatomically accurate L3-L5 lumbar spine model was developed using computed tomography scans. Discography was simulated in the model as an area in the disc affected by needle puncture. The material properties in the nucleus pulposus were adjusted to match experimental data both before and after puncture. The results show that puncture of the IVD leads to increased deformation as well as increased stresses in the disc. Pressure in the nucleus pulposus found to decrease after puncture, and was calculated in the course of this study. Puncturing the IVD changes disc mechanics and may lead to progressive spine issues in the future such as disc degeneration. While discography has been the gold standard to determine if the disc was a source of back pain in patients for many years, the potential long-term degenerative effects of the procedure are only now coming into light, and must be closely examined.

Axial behaviour of slender concrete-filled steel tube square columns strengthened with square concrete-filled steel tube jackets

2019 ◽  
Vol 23 (6) ◽  
pp. 1074-1086 ◽  
Author(s):  
Tao Zhu ◽  
Hongjun Liang ◽  
Yiyan Lu ◽  
Weijie Li ◽  
Hong Zhang
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Bearing Capacity ◽  
Element Model ◽  
Steel Tube ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Concrete Filled Steel Tube ◽  
Experimental Parameters ◽  
Modified Formula

This article investigates the behaviour of slender concrete-filled steel tube square columns strengthened by concrete-filled steel tube jacketing. The columns were realised by placing a square outer steel tube around the original slender concrete-filled steel tube column and pouring strengthening concrete into the gap between the inner and outer steel tubes. Three concrete-filled steel tube square columns and seven retrofitted columns ranging from 1200 to 2000 mm were tested to failure under axial compression. The experimental parameters included three length-to-width ( L/ B1) ratios, three width-to-thickness ( B1/ t1) ratios and three strengths of concrete jacket (C50-grade, C60-grade and C70-grade). Experimentally, the retrofitted columns failed in a similar manner to traditional slender concrete-filled steel tube columns. After strengthening, the retrofitted columns benefitted greatly from the component materials, with their load-bearing capacity and ductility notably enhanced. These enhancements were mainly brought about by sectional enlargement and good confinement of concrete. A finite element model was developed using ABAQUS to better understand the axial behaviour of the retrofitted specimens. A parametric study was conducted, with parameters including the length of the column, thickness of the outer steel tube, strength of the concrete jacket, yield strength of the outer steel tube, thickness of the inner steel tube and strength of the inner concrete. Furthermore, the finite element model was adopted to study the behaviour of rust-damaged and post-fire slender concrete-filled steel tube square columns strengthened by square concrete-filled steel tube jacketing. A modified formula was proposed to predict the load-bearing capacity of retrofitted specimens, and the numerical results agreed well with the experiments and the finite element results of undamaged, rust-damaged and post-fire specimens. It could be used as a reference for practical application.

FINITE ELEMENT ANALYSES ON CORRODED PONY TRUSS BRIDGE FOR REASONABLE MAINTENANCE

2020 ◽  
Vol 7 (2) ◽  
Author(s):  
Risa Fujinaga ◽  
Tatsumasa Kaita ◽  
Ryoko Koyama ◽  
Tsutomu Imai ◽  
Katashi Fujii
Keyword(s):  
Bearing Capacity ◽  
Ultimate Load ◽  
Plane Deformation ◽  
Element Model ◽  
Truss Structures ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Out Of Plane ◽  
Pony Truss Bridge ◽  
Truss Bridge

The load bearing capacity of an existing corroded pony truss bridge, which is used for 100 years was estimated from FEM results for whole bridge model. The beam element model is to clarify that the influence of the residual out-of-plane deformation in main truss structures on the load bearing capacity from the viewpoint of whole bridge. Also, shell element model is to clarify that the influence of severe corrosion damages occurred in many structural members on the load bearing capacity as whole bridge. On the other hand, the influence of assumed support conditions in analytical models were discussed from the analytical results of both type of models, because it will be thought that the performance of shoes deteriorates gradually by long in-service period. The ultimate load bearing capacity was estimated by the critical live load magnification. From the analytical results, the residual out-of-plane deformation of main truss structures in this bridge had little influence on the ultimate load bearing capacity. Also, the ultimate load bearing capacity may decrease up to 20% due to aging deterioration of shoes including corrosion damages. In bridge maintenance, it should be paid attention on local severe corrosion damages on the structural member, which may occur higher secondary stress.

scholarly journals Analysis of Load-Bearing Capacity of Initial lining in Tunnels

2021 ◽  
Vol 9 (VII) ◽  
pp. 3954-3960
Author(s):  
MD Waquar Alam
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Bearing Capacity ◽  
Element Model ◽  
Time Dependent ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Full Face ◽  
Ground Condition ◽  
Drill And Blast

Large displacements during excavation are regularly observed in Squeezing ground condition and Rock-burst condition with high overburden. The expected displacement has to be estimated prior to excavation to provide enough allowance for the displacements. The support system need to be well-suited through the estimated imposed strains. As the estimated displacements and thus the strains in the support depend upon the load-bearing capacity of support. The ratio of uniaxial compressive strength of rock mass to maximal insitu stress determines tunnel integrity in the weak region.This ratio estimates the requirements of initial lining to control strain to a stipulated level. The elasto-plastic theory may deliver definitive forecasts providing the strength limitations of rock masses are identified accurately. With the help of empirical analysis, the development of displacements for diverse advance rates and supports can be concluded. As a consequence, a quantitative finite element model based on an advanced built-in model is designed to analyse the load-bearing efficiency of initial lining although taking into consideration the time-dependent and non-linear material behaviour of initial lining. The time-dependent excavation mechanism of the drill-and-blast approach for tunnels guided by full face excavation is considered in the finite element model. The material parameters for the initial lining were computed based on case studies- (A Chibro-Khodri Hydropower Tunnel).

scholarly journals Development of a Detailed Volumetric Finite Element Model of the Spine to Simulate Surgical Correction of Spinal Deformities

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Mark Driscoll ◽  
Jean-Marc Mac-Thiong ◽  
Hubert Labelle ◽  
Stefan Parent
Keyword(s):  
Finite Element ◽  
Intervertebral Disc ◽  
Finite Element Model ◽  
Ex Vivo ◽  
Spinal Instrumentation ◽  
Element Model ◽  
Patient Data ◽  
Biomechanical Analysis ◽  
Published Data

A large spectrum of medical devices exists; it aims to correct deformities associated with spinal disorders. The development of a detailed volumetric finite element model of the osteoligamentous spine would serve as a valuable tool to assess, compare, and optimize spinal devices. Thus the purpose of the study was to develop and initiate validation of a detailed osteoligamentous finite element model of the spine with simulated correction from spinal instrumentation. A finite element of the spine from T1 to L5 was developed using properties and geometry from the published literature and patient data. Spinal instrumentation, consisting of segmental translation of a scoliotic spine, was emulated. Postoperative patient and relevant published data of intervertebral disc stress, screw/vertebra pullout forces, and spinal profiles was used to evaluate the models validity. Intervertebral disc and vertebral reaction stresses respected publishedin vivo,ex vivo, andin silicovalues. Screw/vertebra reaction forces agreed with accepted pullout threshold values. Cobb angle measurements of spinal deformity following simulated surgical instrumentation corroborated with patient data. This computational biomechanical analysis validated a detailed volumetric spine model. Future studies seek to exploit the model to explore the performance of corrective spinal devices.

Finite Element Analysis of Lightweight Energy-Saving Composite Floor

2014 ◽  
Vol 665 ◽  
pp. 196-202
Author(s):  
Yi Qing Guo ◽  
Ping Zhou Cao
Keyword(s):  
Finite Element ◽  
Elastic Modulus ◽  
Bearing Capacity ◽  
Energy Saving ◽  
Element Model ◽  
Finite Element Models ◽  
Load Bearing Capacity ◽  
Element Analysis ◽  
Load Bearing ◽  
Thin Panel

In order to study the performance of lightweight energy-saving composite floor, the finite element models of composite floor were established, which was based on the composite floor specimens test research. The finite element models were verified rationally and correctly in the paper, through compared with the composite floor test results. The finite element model can be used to analyze the load-bearing capacity of composite floor. Various influencing factors of composite floor with simply supported end were analyzed, such as the span of self-tapping screw, the diameter of self-tapping screw, the strength of thin panel and the elastic modulus of thin panel, etc. The results show that the load-bearing capacity of composite floor increases with the increase of the number of self-tapping screw, the diameter of self-tapping screw, the strength of thin panel and the elastic modulus of thin panel, etc. The load-bearing capacity calculate formula of composite floor was proposed.

scholarly journals Prediction of Load-Bearing Capacity of Composite Parts with Low-Velocity Impact Damage: Identification of Intra- and Inter-Ply Constitutive Models

2020 ◽  
Vol 1 (1) ◽  
pp. 59-78
Author(s):  
Aleksandr Cherniaev ◽  
Svetlana Pavlova ◽  
Aleksandr Pavlov ◽  
Valeriy Komarov
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Bearing Capacity ◽  
Damage Mechanics ◽  
Impact Damage ◽  
Element Model ◽  
Physical Parameters ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Simulation Methodology

Assessments of residual load-carrying capacity are often conducted for composite structural components that have received impact damage. The availability of a verified simulation methodology can provide significant cost savings when such assessments are required. To support the development of a reliable and accurate simulation methodology, this study investigated the predictive capabilities of a stacked solid-shell finite element model of a cylindrical composite component with a damage mechanics-based description of the intra-ply material response and a cohesive contact model used for simulation of the inter-ply behavior. Identification of material properties for the model was conducted through mechanical characterization. Special attention was paid to understanding the influence of non-physical parameters of the intra- and inter-ply material models on predicting compressive failure load of damaged composite cylinders. Calibration of the model conducted using the response surface methodology allowed for identifying rational values of the non-physical parameters. The results of simulations with the identified and calibrated finite element model showed reasonable correlation with experimental data in terms of the predicted failure loads and post-impact and post-failure damage modes. The investigated modeling technique can be recommended for evaluating the residual load-bearing capacity of flat and curved composite parts with impact damage working under the action of compressive loads.

scholarly journals The influence of cutouts in slabs of formwork-free molding on their load-bearing capacity

2021 ◽  
Vol 18 (5) ◽  
pp. 63-69
Author(s):  
S. V. Tsybakin ◽  
◽  
M. G. Plyusnin ◽  
A. N. Zotov ◽  
◽  
...  
Keyword(s):  
Bearing Capacity ◽  
Cross Section ◽  
Numerical Study ◽  
Element Model ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Capacity Reduction ◽  
Reinforcement Value ◽  
The Finite Element Model ◽  
Partial Compensation

The paper presents the results of testing the slab of formwork-free molding (PB slab) for strength, as well as numerical study of the finite element model of this slab. It is shown that with an angular cutout in the PB slab, its load bearing capacity decreases and the nature of fracture changes. Partial compensation for the load-bearing capacity reduction of the slab with such a cutout can be achieved by reducing the pre-stressing reinforcement value of reinforcement rods cut off during the formation of the cutout, or by redistributing the reinforcement along the cross-section of the slab.

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