scholarly journals Biomechanical Analysis Using FEA and Experiments of Metal Plate and Bone Strut Repair of a Femur Midshaft Segmental Defect

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Jason Coquim ◽  
Joseph Clemenzi ◽  
Mohsen Salahi ◽  
Abdurahman Sherif ◽  
Pouria Tavakkoli Avval ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Cortical Bone ◽  
Metal Plate ◽  
Biomechanical Analysis ◽  
Von Mises Stress ◽  
Segmental Defect ◽  
Lateral Plate ◽  
Repair Technique ◽  
Von Mises

This investigation assessed the biomechanical performance of the metal plate and bone strut technique for fixing recalcitrant nonunions of femur midshaft segmental defects, which has not been systematically done before. A finite element (FE) model was developed and then validated by experiments with the femur in 15 deg of adduction at a subclinical hip force of 1 kN. Then, FE analysis was done with the femur in 15 deg of adduction at a hip force of 3 kN representing about 4 x body weight for a 75 kg person to examine clinically relevant cases, such as an intact femur plus 8 different combinations of a lateral metal plate of fixed length, a medial bone strut of varying length, and varying numbers and locations of screws to secure the plate and strut around a midshaft defect. Using the traditional “high stiffness” femur-implant construct criterion, the repair technique using both a lateral plate and a medial strut fixed with the maximum possible number of screws would be the most desirable since it had the highest stiffness (1948 N/mm); moreover, this produced a peak femur cortical Von Mises stress (92 MPa) which was below the ultimate tensile strength of cortical bone. Conversely, using the more modern “low stiffness” femur-implant construct criterion, the repair technique using only a lateral plate but no medial strut provided the lowest stiffness (606 N/mm), which could potentially permit more in-line interfragmentary motion (i.e., perpendicular to the fracture gap, but in the direction of the femur shaft long axis) to enhance callus formation for secondary-type fracture healing; however, this also generated a peak femur cortical Von Mises stress (171 MPa) which was above the ultimate tensile strength of cortical bone.

Asymmetric 6-Strand Flexor Tendon Repair – Biomechanical Analysis Using Barbed Suture

2019 ◽  
Vol 24 (03) ◽  
pp. 297-302
Author(s):  
Jasmin Shimin Lee ◽  
Yoke-Rung Wong ◽  
Shian-Chao Tay
Keyword(s):  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Flexor Tendon ◽  
Tendon Repair ◽  
Biomechanical Analysis ◽  
Barbed Suture ◽  
Flexor Tendon Repair ◽  
Barbed Sutures ◽  
Repair Technique ◽  
Nylon Suture

Background: This study investigates the biomechanical performance of the Asymmetric flexor tendon repair technique using barbed suture. The Asymmetric repair technique using monofilament nylon suture was previously reported to have a higher tensile strength than the modified Lim-Tsai repair technique, but its repair stiffness and load to gap force were significantly lower. There is hence an unmet need to improve this technique and the substitution of nylon suture with barbed sutures may be the solution. Methods: Two groups consisting of 10 porcine tendons each were repaired with the six-strand Asymmetric repair technique using V-Loc® 3-0 and Supramid® 4-0 respectively. The repairs were subjected to a mechanical tester for static testing. The ultimate tensile strength, load to 2 mm gap force, repair stiffness, time taken to complete a repair and failure mechanism of the repairs were recorded and analyzed. Results: All the repairs using V-Loc® 3-0 sutures had significantly higher median values of ultimate tensile strength (64.1 N; 56.9 N), load to 2 mm gap force (39.2 N; 19.7 N), repair stiffness (6.4 N/mm; 4.7 N/mm) and time taken to complete a repair (9.4 mins; 7.7 mins). All the repairs using V-Loc® sutures failed by suture breakage while 80% of repairs using Supramid® sutures failed by suture pullout. Conclusions: The use of the barbed sutures in the Asymmetric repair technique, whilst more time consuming, has shown promising improvement to its biomechanical performance (i.e. better ultimate tensile strength, stiffness and resistance to gap formation).

Altered Load Transfer in the Pelvis in the Presence of Periprosthetic Osteolysis

2014 ◽  
Vol 136 (11) ◽  
Author(s):  
Jacob T. Munro ◽  
Justin W. Fernandez ◽  
James S. Millar ◽  
Cameron G. Walker ◽  
Donald W. Howie ◽  
...  
Keyword(s):  
Cortical Bone ◽  
Load Transfer ◽  
Von Mises Stress ◽  
Patient Specific ◽  
Fe Model ◽  
Stress Concentrations ◽  
Periprosthetic Osteolysis ◽  
Total Hip ◽  
Long Term Follow Up ◽  
Von Mises

Periprosthetic osteolysis in the retroacetabular region with cancellous bone loss is a recognized phenomenon in the long-term follow-up of total hip replacement. The effects on load transfer in the presence of defects are less well known. A validated, patient-specific, 3D finite element (FE) model of the pelvis was used to assess changes in load transfer associated with periprosthetic osteolysis adjacent to a cementless total hip arthroplasty (THA) component. The presence of a cancellous defect significantly increased (p < 0.05) von Mises stress in the cortical bone of the pelvis during walking and a fall onto the side. At loads consistent with single leg stance, this was still less than the predicted yield stress for cortical bone. During higher loads associated with a fall onto the side, highest stress concentrations occurred in the superior and inferior pubic rami and in the anterior column of the acetabulum with larger cancellous defects.

scholarly journals Effects of placement angle and direction of orthopedic force application on the stability of orthodontic miniscrews

2012 ◽  
Vol 83 (4) ◽  
pp. 667-673 ◽  
Author(s):  
Jihye Lee ◽  
Ji Young Kim ◽  
Yoon Jeong Choi ◽  
Kyung-Ho Kim ◽  
Chooryung J. Chung
Keyword(s):  
Cortical Bone ◽  
Lateral Force ◽  
Von Mises Stress ◽  
Biomechanical Stability ◽  
Element Analysis ◽  
Force Application ◽  
Pull Out ◽  
The Stability ◽  
Von Mises ◽  
Pull Out Strength

ABSTRACT Objectives: To evaluate the influence of placement angle and direction of orthopedic force application on the stability of miniscrews. Materials and Methods: Finite element analysis was performed using miniscrews inserted into supporting bone at angles of 90°, 60°, and 30° (P90°, P60°, and P30°). An orthopedic heavy force of 800 gf was applied to the heads of the miniscrews in four upward (U0°, U30°, U60°, U90°) or lateral (L0°, L30°, L60°, L90°) directions. In addition, pull-out strength of the miniscrews was measured with various force directions and cortical bone thicknesses. Results: Miniscrews with a placement angle of 30° (P30°) and 60° (P60°) showed a significant increase in maximum von Mises stress following the increase in lateral force vectors (U30°, U60°, U90°) compared to those with a placement angle of 90° (P90°). In accordance, the pull-out strength was higher with the axial upward force when compared to the upward force with lateral vectors. Maximum von Mises stress and displacement of the miniscrew increased as the angle of lateral force increased (L30°, L60°, L90°). However, a more dramatic increase in maximum von Mises stress was noted in P30° than in P60° and P90°. Conclusion: Placement of the miniscrew perpendicular to the cortical bone is advantageous in terms of biomechanical stability. Placement angles of less than 60° can reduce the stability of miniscrews when orthopedic forces are applied in various directions.

scholarly journals Simulation-based Prediction of Structural Design Failure in Fishing Deck Machinery a Hydraulic Type with Finite Element Method

2019 ◽  
Vol 130 ◽  
pp. 01001
Author(s):  
Agri Suwandi ◽  
Dede Lia Zariatin ◽  
Bambang Sulaksono ◽  
Estu Prayogi ◽  
I Made Widana
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Structural Design ◽  
Simulation Analysis ◽  
Poisson Ratio ◽  
Von Mises Stress ◽  
Material Base ◽  
Element Method

The fishing deck machinery is the tools used to collect fish in fishing activities. Fishing deck machinery is intended to improve the effectiveness of fishing operations. The mission of the Ministry of Marine Affairs and Fishery Year 2015-2019 in the Regulation of the Minister of Marine and Fisheries No. 45/PERMEN-KP/2015 which is a priority is to provide assistance for fishing facilities for fishermen; it is necessary to develop and optimize fishing deck machinery. To assure the safety and dependability of these fishing deck machinery, calculations, simulation and functional tests are needed. This paper discusses the prediction of structural failure in the design of fishing deck machinery a hydraulic type with finite element method simulation approach. The results of the FEM simulation analysis are (i) the maximum value of von-Mises stress is greater than the ultimate tensile strength of the material; (ii) 1st principal stress value minimum is smaller than the ultimate tensile strength of material; (iii). the Poisson ratio value higher than the Poisson ratio value of the material. Base on the simulation result, the structural design of fishing deck machinery is safety.

Based on the Finite Element Software ANSYS/LS-DYNA Metal Plate Covering Parts Forming Process Simulation and Optimization Research

2014 ◽  
Vol 912-914 ◽  
pp. 589-592
Author(s):  
Jin Ling Wang
Keyword(s):  
Finite Element ◽  
Sheet Metal ◽  
Metal Plate ◽  
Von Mises Stress ◽  
Skilled Workers ◽  
Forming Process ◽  
Simulation And Optimization ◽  
Finite Element Software ◽  
Stamping Process ◽  
Von Mises

The design of cold punching mould CAD/CAM and the combination of CAE analysis can advance analysis of stamping process program, eventually get ideal stamping parameters, realize design automation, save resources and reduce dependence on experience, reduce the demand for skilled workers. This paper, by using nonlinear dynamic finite element software ANSYS/ls-dyna continuous function, simulation of sheet metal forming process and unloading plate deformation, forming process, at any time throughout the von mises stress nephogram should rebound and strain values and unloading plate material as a result, analysis help us better understand the changes of the internal material sheet metal stamping process.

Effect of Composite Fibers Orientations on Crack Behavior of a Thin Plate by Finite Element Method Simulation

2014 ◽  
Vol 875-877 ◽  
pp. 1027-1031
Author(s):  
A. Hocine ◽  
M. Saidi ◽  
S.M. Medjdoub ◽  
M. Hadj Meliani
Keyword(s):  
Stress Intensity ◽  
Finite Element Method Simulation ◽  
Tensile Loading ◽  
Metal Plate ◽  
Von Mises Stress ◽  
Intensity Factors ◽  
Crack Behavior ◽  
Composite Layers ◽  
Von Mises ◽  
Cracked Structure

The present study is a preliminary effort which investigates the effect of different sequences of composite materials on the Von Mises stress and stress concentration factor on a simple thin cracked plate. Our approach is to reduce the design of cylinder under internal pure pressure to that of a cracked metal plate reinforced by different sequences layers of composite subjected to a tensile loading. Four reports of the length of the crack front (a) with respect to the thickness (t) of the structure were analyzed. The increased ratio (a/t) from 10% to 40% positively influences the values of stress intensity factors and the Von Mises stress. Finally, the numerical results show that the reinforced the cracked structure with composite layers has greatly reduced the stress intensity factor at the crack tip based on fiber orientations.

Study the Strength of Material and Composite Structures of Belly-Landing Mini UAV

2016 ◽  
Vol 842 ◽  
pp. 178-185 ◽  
Author(s):  
Maria Fransisca Soetanto ◽  
Rachmad Imbang Tritjahjono
Keyword(s):  
Tensile Strength ◽  
Composite Materials ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Von Mises Stress ◽  
Uniaxial Tensile ◽  
Specific Strength ◽  
Specific Stiffness ◽  
Von Mises ◽  
Material Composite

This paper consists of the design and analysis of the strength of material composite of the fuselage of a Belly-Landing Mini Unmanned Aerial Vehicle (UAV). A belly landing UAV occurs when an UAV lands without its landing gear and uses its underside, or belly, as its primary landing device. Belly landings carry the risk that the UAV may flip over, disintegrate, or catch fire if it lands too fast or too hard [1], so the more important designs parameters for materials used are the specific strength and specific stiffness. Specific strength is defined as the ultimate tensile strength divided by material density, and specific stiffness is defined as Young’s modulus of the material divided by density [Franklin, 2010]. The aim of this Belly Landing Mini UAV is for used in situations where manned flight is considered too risky or difficult and no runway for take-off or landing, such as fire fighting surveillance, while the term 'mini’ means the design of this UAV has a launch mass greater than 100 grams but less than 100 kilograms [2], the objective of this project is the development and design of materials fuselage of a mini UAV with two layer sandwich structures made from composite materials and epoxy resin. For that purposes, 3 variations of the composite materials tensile test specimens have been manufactured in accordance with ASTM D3039 standard and tested its strength. The results showed that the fibre glass and fibre carbon composite with resin epoxy has the maximum tensile strength and Young’s modulus, so that the fabrication and manufacturing of the fuselage component is made by using that material composite. The Von Mises stress is used to predict yielding of materials under any loading condition from results of simple uniaxial tensile tests by using software Autodesk Inventor 2012. The results show that the design is safe caused the strength of material is greater than the maximum value of Von Mises stress induced in the material. The results of flight tests show that this small UAV has successfully manoeuvred to fly, such as take off, some acrobatics when cruising and landing smoothly, which means that the calculation and analysis of structure and material used on the fuselage of the Mini UAV was able to be validated.

A New Anchorage Device for Orthodontic Applications

2013 ◽  
Author(s):  
Mohamad Najari ◽  
Marwan El-Rich ◽  
Samer Adeeb ◽  
Bachar Taha
Keyword(s):  
Cortical Bone ◽  
Shear Force ◽  
Vertical Shear ◽  
Von Mises Stress ◽  
Fe Method ◽  
Screw Head ◽  
Load Bearing ◽  
New Device ◽  
Von Mises ◽  
Orthodontic Forces

In orthodontic treatment, anchorage is the most important element that affects the treatment’s success. To improve the load bearing capacity of the anchorage there are several devices developed in recent decades such as midpalatal implants and onplants but they also have limitation on directions of applied load and their support position adjustability. The purpose of this study was to investigate the efficiency of a new anchorage device by analyzing the load-bearing and stress distribution among the cortical and cancellous bones of the mandible as well as the anchorage system components using nonlinear 3D Finite Element (FE) method. The new device is composed of an adjustable stainless steel plate equipped with bracket and mounted with two titanium mini-screws into the mandible. The response of this new system was compared to an isolated mini-screw system under different loading scenarios. A maximum of 500gr force was applied in different directions on the bracket and the isolated mini-screw head to simulate the orthodontic loading. Using the new anchorage device reduced von-Mises stress in the whole structure approximately by 50% comparing to the isolated mini-screw. In the cortical bone and depending on the direction of the applied force, von-Mises stress decreased from 6 to 3MPa under vertical shear force and from 6 to 1.5MPa under horizontal and inclined shear forces. In the cancellous bone the stress decreased similarly as in the cortical bone from 0.6 to ≈0.3MPa under horizontal and inclined shear. Under vertical shear force the decrease was less significant from 0.57MPa to 0.5MPa. This new device while offering wide fields of orthodontic forces applications thanks to its bracket provides the same resistive force (500gr) as the isolated mini-screw with much lower stresses in the bone and anchorage implant as well. The next step is to investigate the efficiency of this new device in the teeth movement.

scholarly journals The Influence of Pelvic Tilt on Stress Distribution in the Acetabulum: Finite Element Analysis

2020 ◽  
Author(s):  
Kazuhiro Hasegawa ◽  
Tamon Kabata ◽  
Yoshitomo Kajino ◽  
Daisuke Inoue ◽  
Jiro Sakamoto ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Hip Joint ◽  
Tilt Angle ◽  
Pelvic Tilt ◽  
Biomechanical Analysis ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Von Mises

Abstract Background Finite element analysis (FEA) has been previously applied for the biomechanical analysis of acetabular dysplasia and osteotomy. However, until now, there have been little reports on the use of FEA to evaluate the effects of pelvic tilt on stress distribution in the acetabulum. Methods We used the Mechanical Finder Ver. 7.0 (RCCM, Inc., Japan) to construct finite element models based on 3D-CT data of patients, and designed dysplasia, borderline, and normal pelvic models. For analysis, body weight was placed on the sacrum and the load of the flexor muscles of the hip joint was placed on the ilium. The pelvic tilt was based on the anterior pelvic plane, and the pelvic tilt angles were -20°, 0°, and 20°. The load of the flexor muscle of the hip joint was calculated using the moment arm equation.Results All three models showed the highest values of von Mises stress in the -20° pelvic tilt angle, and the lowest in the 20° angle. Stress distribution concentrated in the load-bearing area. The maximum values of von Mises stress in the borderline at pelvic tilt angles of -20° was 3.5Mpa, and in the dysplasia at pelvic tilt angles of 0° was 3.1Mpa. Conclusions The pelvic tilt angle of -20° of the borderline model showed equal maximum values of von Mises stress than the dysplasia model of pelvic tilt angle of 0°, indicating that pelvic retroversion of -20° in borderline is a risk factor for osteoarthritis of the hip joints, similar to dysplasia.

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