scholarly journals INFLUENCE OF THE SAGITTAL LUMBAR PARAMETERS ON THE STRESS-STRAIN STATE OF THE SPINAL MOTOR SEGMENTS AT TRANSPEDICULAR FIXATION

2021 ◽  
pp. 37-48
Author(s):  
Barkov Barkov ◽  
Oleg Veretelnik ◽  
Mykola Tkachuk ◽  
Mykola А. Tkachuk ◽  
Victor Veretelnik
Keyword(s):  
Lumbar Spine ◽  
Intervertebral Disc ◽  
Cortical Bone ◽  
Lumbar Lordosis ◽  
Strain State ◽  
Maximum Stress ◽  
Stress Strain ◽  
Stress Strain State ◽  
Spinal Motor ◽  
Human Lumbar Spine

Objective. To study the stress-strain state of the elements of the human lumbar spine when we use the transpedicular system, taking into account different angular values of segmental and total lumbar lordosis. Methods. For computer modeling of the stress-strain state of the elements of the human lumbar spine after mono- and polysegmental fixation, the Workbench product was used, and for the construction of parametric three-dimensional geometricmodels — the SolidWorks computer-aided design system was used. 4 groups of decisions were studied, which differed in angular values of segmental and total lumbar lordosis. In each group, 11 models were analyzed that describe the lumbar segments after mono- and polysegmental fixation in various configurations of the sagittal alignment of the lumbar spine. Results. It was found that the maximum stress on the cortical bone is concentrated on the base of the LV in case of the «pathological» intervertebral disc LV–S in the group of patients with hyperlordosis. At polysegmental fixation of the LI – S, there is a redistribution of stress on the cortical bone of all vertebrae, the maximum values of which is present in the bodies of the LV and S vertebrae. And only in the group with hypolordosis this stress is minimal. The maximum stress was always on the overlying intervertebral disc during transpedicularfixation. Significant increasing of cartilage stress in the facet joints of the LIV–LV segment was recorded during fixation of the LV–S segmentin case of hyperlordosis. The maximum stress on the rods was identified in the group of patients with hyperlordosis and polysegmentalfixation of the LI –S, on screws — on LV, LIV, LIII vertebrae during fixation in all groups, except for hypolordosis. Conclusions. Increasing in angular values (hyperlordosis), which describe segmental and total lumbar lordosis, leads to the stress elevation in the fixing elements and structures of the spinal motor segments, and, conversely, a decreasing in angular values (hypolordosis) causes the stress falling.

scholarly journals Stress-strain state of a composite near rectangular inclusion

2018 ◽  
Vol 243 ◽  
pp. 00021
Author(s):  
Pavel Pisarev ◽  
Aleksandr Anoshkin ◽  
Vladislav Ashihmin
Keyword(s):  
Numerical Simulations ◽  
Numerical Experiments ◽  
Strain State ◽  
Maximum Stress ◽  
Three Dimensional ◽  
Thermoplastic Composite ◽  
Model Construction ◽  
Stress Strain ◽  
Stress Strain State ◽  
Rectangular Inclusion

In this research we developed a technique for calculating the stress-strain state of a model construction from a thermoplastic composite material with an embedded piezoactuator. Numerical simulations of the model construction stress-strain state with different arrangement of piezoactuators: upper and middle,-were performed. Numerical simulations were carried out in a three-dimensional setting taking into account the complete technological scheme of laying and anisotropy of the properties of reinforcing layers. The results of numerical experiments revealed the areas of maximum stress. Recommendations for the MFC’s embedding into composite materials were formulated.

scholarly journals АНАЛІЗ НАПРУЖЕНО-ДЕФОРМОВАНОГО СТАНУ ФІТИНГОВОГО СТИКУ ПАНЕЛЕЙ ВІД'ЄМНОЇ ЧАСТИНИ КРИЛА ТА ЦЕНТРОПЛАНА ТРАНСПОРТНОГО ЛІТАКА

2021 ◽  
pp. 97-112
Author(s):  
Yifang Sun ◽  
А. А. Вендин
Keyword(s):  
Strain State ◽  
Maximum Stress ◽  
Solid Model ◽  
Force Distribution ◽  
Maximum Strain ◽  
Stress Strain ◽  
Element Analysis ◽  
Wing Section ◽  
Stress Strain State ◽  
Center Section

Fitting joints are widely used in aircraft structures, and they are responsible for the interconnection of important components. The stress-strain state analysis of the fitting joint must be carried out before the performance analysis of the fitting joint. With the help of 3D modeling software (CATIA) and finite element analysis software (ANSYS), the stress-strain state of each component in the fitting joint of outer wing section was calculated in this paper. In the CATIA, the solid model is simplified and segmented according to the size of the cross section and the height of the center of gravity of the model. In the ANSYS, the beam elements are used to replace the simplified segmented model to obtain the internal force distribution of the solid model and to determine the magnitude and change law of the stress applied to the end of the solid model. When calculating the force transmitted by the fastener, the pre-tightening force of the bolt and the interaction between the surfaces of the component are taken into account, so as to simulate the real force situation well. Therefore, it is a very feasible method to use the CATIA and ANSYS to obtain the stress-strain state of components in the fitting joint of center wing section and outer wing section.The results show that under the working conditions of the fitting joint (130Mpa), the fitting of outer wing section with center section has a maximum stress of 245.79Mpa and a maximum strain of 0.0035, the stringer of outer wing section has a maximum stress of 293.17Mpa and a maximum strain of 0.0047, the lower panel of outer wing section has a maximum stress of 289.53Mpa and a maximum strain of 0.0042. The connecting bolts (M8 and M6) have a maximum stress of 686.81Mpa and a maximum strain of 0.0063, which meets the design requirements. In addition, according to the analysis results of the stress-strain state of the fitting joint of outer wing section, the force distribution of the bolts in the fitting joint of outer wing section with center section was obtained in this paper. It has been confirmed that due to the different positions and force areas of the bolts, the force distribution between rows of bolts is uneven, and the first row of bolts has a more force.

scholarly journals STRESS-STRAIN STATE OF THE SYSTEM "LUMBAR SPINE-SACRUM-PELVIS" IN THE CONDITIONS OF FRONT PELVIS

2016 ◽  
Vol 0 (1) ◽  
pp. 54
Author(s):  
Mykola Korzh ◽  
Volodymyr Staude ◽  
Andrey Kondratyev ◽  
Mykhaylo Karpinsky
Keyword(s):  
Lumbar Spine ◽  
Strain State ◽  
Stress Strain ◽  
Stress Strain State

scholarly journals Numerical Modeling of Stress-Strain State of a Deep Beam

2019 ◽  
Vol 221 ◽  
pp. 01032
Author(s):  
Nikita Mescheulov ◽  
Vladimir Barashkov
Keyword(s):  
Strain State ◽  
Maximum Stress ◽  
Maximum Load ◽  
Support Surface ◽  
Deep Beam ◽  
Stress Strain ◽  
Stress Strain State ◽  
Entire Thickness ◽  
Calculation Results ◽  
Axis Of Symmetry

The article presents calculation results for model elastic problem of defining stress-strain state of a deep beam preformed in 3D and 2D statements with the use of ANSYS software package. Geometric relations are taken in the form of Cauchy equations. The purpose of the study is to assess error in the results obtained for the two statements and to draw a conclusion on the possibility of using 2D statement for the deep beam under study. Based on 3D statement calculation results one may observe a short area near the support surface of a deep beam with the maximum load across the entire thickness. In this area the concentration of maximum stress values and maximum linear and angular deformations in the structure material are observed. The area is located on the axis of symmetry of the deep beam near the inner edge of support surface. It is found that the stress intensity values obtained for the two statements have considerable differences in this area, for that reason 3D statement shall be used when performing calculations for the deep beam. This way of solving the problem is illustrative of stress-strain state parameters distribution across the thickness of the structure, which is necessary for its strength evaluation.

КОНСТРУКТИВНО-ТЕХНОЛОГІЧНІ ОСОБЛИВОСТІ ХВОСТО-ВИХ БАЛОК СІТЧАСТОГО ТИПУ З ПОЛІМЕРНИХ КОМПО-ЗИЦІЙНИХ МАТЕРІАЛІВ ВЕРТОЛЬОТІВ ТРАНСПОРТНОЇ КАТЕГОРІЇ

2020 ◽  
pp. 15-30
Author(s):  
А. Г. Гребеников ◽  
И. В. Малков ◽  
В. А. Урбанович ◽  
Н. И. Москаленко ◽  
Д. С. Колодийчик
Keyword(s):  
Finite Element ◽  
Strain State ◽  
Layer Structure ◽  
Metal Structure ◽  
Element Model ◽  
Stress Strain ◽  
Element Analysis ◽  
Mesh Structure ◽  
Stress Strain State ◽  
Mesh Structures

The analysis of the design and technological features of the tail boom (ТB) of a helicopter made of polymer composite materials (PCM) is carried out.Three structural and technological concepts are distinguished - semi-monocoque (reinforced metal structure), monocoque (three-layer structure) and mesh-type structure. The high weight and economic efficiency of mesh structures is shown, which allows them to be used in aerospace engineering. The physicomechanical characteristics of the network structures are estimated and their uniqueness is shown. The use of mesh structures can reduce the weight of the product by a factor of two or more.The stress-strain state (SSS) of the proposed tail boom design is determined. The analysis of methods for calculating the characteristics of the total SSS of conical mesh shells is carried out. The design of the tail boom is presented, the design diagram of the tail boom of the transport category rotorcraft is developed. A finite element model was created using the Siemens NX 7.5 system. The calculation of the stress-strain state (SSS) of the HC of the helicopter was carried out on the basis of the developed structural scheme using the Advanced Simulation module of the Siemens NX 7.5 system. The main zones of probable fatigue failure of tail booms are determined. Finite Element Analysis (FEA) provides a theoretical basis for design decisions.Shown is the effect of the type of technological process selected for the production of the tail boom on the strength of the HB structure. The stability of the characteristics of the PCM tail boom largely depends on the extent to which its design is suitable for the use of mechanized and automated production processes.A method for the manufacture of a helicopter tail boom from PCM by the automated winding method is proposed. A variant of computer modeling of the tail boom of a mesh structure made of PCM is shown.The automated winding technology can be recommended for implementation in the design of the composite tail boom of the Mi-2 and Mi-8 helicopters.

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