Investigating the crack stress shielding effect by using photoelastic and acoustic imaging techniques

1991 ◽  
Vol 14 (3) ◽  
pp. 151-164
Author(s):  
C.T. Liu ◽  
C.W. Smith
Keyword(s):  
Imaging Techniques ◽  
Stress Shielding ◽  
Acoustic Imaging ◽  
Shielding Effect

scholarly journals Design of Customize Interbody Fusion Cages of Ti64ELI with Gradient Porosity by Selective Laser Melting Process

Micromachines ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 307
Author(s):  
Cheng-Tang Pan ◽  
Che-Hsin Lin ◽  
Ya-Kang Huang ◽  
Jason S. C. Jang ◽  
Hsuan-Kai Lin ◽  
...  
Keyword(s):  
Stress Concentration ◽  
Selective Laser Melting ◽  
Stress Shielding ◽  
Simulation Software ◽  
Surrounding Tissue ◽  
Shielding Effect ◽  
Stress And Strain ◽  
Laser Melting ◽  
Flexion Extension ◽  
Intervertebral Cage

Intervertebral fusion surgery for spinal trauma, degeneration, and deformity correction is a major vertebral reconstruction operation. For most cages, the stiffness of the cage is high enough to cause stress concentration, leading to a stress shielding effect between the vertebral bones and the cages. The stress shielding effect affects the outcome after the reconstruction surgery, easily causing damage and leading to a higher risk of reoperation. A porous structure for the spinal fusion cage can effectively reduce the stiffness to obtain more comparative strength for the surrounding tissue. In this study, an intervertebral cage with a porous gradation structure was designed for Ti64ELI alloy powders bonded by the selective laser melting (SLM) process. The medical imaging software InVesalius and 3D surface reconstruction software Geomagic Studio 12 (Raindrop Geomagic Inc., Morrisville, NC, USA) were utilized to establish the vertebra model, and ANSYS Workbench 16 (Ansys Inc, Canonsburg, PA, USA) simulation software was used to simulate the stress and strain of the motions including vertical body-weighted compression, flexion, extension, lateral bending, and rotation. The intervertebral cage with a hollow cylinder had porosity values of 80–70–60–70–80% (from center to both top side and bottom side) and had porosity values of 60–70–80 (from outside to inside). In addition, according to the contact areas between the vertebras and cages, the shape of the cages can be custom-designed. The cages underwent fatigue tests by following ASTM F2077-17. Then, mechanical property simulations of the cages were conducted for a comparison with the commercially available cages from three companies: Zimmer (Zimmer Biomet Holdings, Inc., Warsaw, IN, USA), Ulrich (Germany), and B. Braun (Germany). The results show that the stress and strain distribution of the cages are consistent with the ones of human bone, and show a uniform stress distribution, which can reduce stress concentration.

In-Duct Acoustic Source Detection Using Acoustic Imaging Techniques

2013 ◽  
Author(s):  
Arthur Finez ◽  
Xavier Mettelle ◽  
Christophe Picard ◽  
Romain Leneveu ◽  
Pascal Souchotte
Keyword(s):  
Imaging Techniques ◽  
Acoustic Imaging ◽  
Source Detection ◽  
Acoustic Source

scholarly journals Bioactivity of PEEK GRF30 and Ti6Al4V SLM in Simulated Body Fluid and Hank’s Balanced Salt Solution

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2059
Author(s):  
Piotr Prochor ◽  
Żaneta Anna Mierzejewska
Keyword(s):  
Simulated Body Fluid ◽  
Salt Solution ◽  
Body Fluid ◽  
Stress Shielding ◽  
Shielding Effect ◽  
Orthopedic Implant ◽  
New Materials ◽  
Optical Analysis ◽  
Calcium Phosphate Layer ◽  
Cylindrical Samples

In recent years, scientists have defined two main paths for orthopedic implant fabrication: searching for new materials with properties closest to natural bone in order to reduce the stress-shielding effect or creating individually adapted geometry of the implant with the use and Rapid Prototyping methods. Therefore, materials such as PEEK GRF30 and Ti6Al4V selective laser melting (SLM) are of interest. They are defined as materials suitable for implants, however, the knowledge of their bioactivity, a feature which is one of the most desirable properties of biomaterials, is still insufficient. Using Simulated Body Fluid and Hank’s Balanced Salt Solution, the bioactivity of PEEK GRF30 and Ti6Al4V SLM was assessed, as well as commercial Ti6Al4V as a reference material. Ten cylindrical samples of each material were prepared and immersed in solutions per period from 2 to 28 days at 37 °C. Optical analysis of the changes on the examined surfaces suggested that right after 2-day crystals with different morphologies were formed on each material. Further analysis of the chemical composition of the altered surfaces confirmed the formation of a calcium phosphate layer on them, however, the Ca/P ratio was slightly different from 1.67. On the basis of the obtained results, it can be concluded that both PEEK GRF30 and Ti6Al4V SLM are characterized by appropriate—comparable to Ti6Al4V—bioactivity.

scholarly journals Topology Optimization to Reduce the Stress Shielding Effect for Orthopedic Applications

Procedia CIRP ◽  
2017 ◽  
Vol 65 ◽  
pp. 202-206 ◽  
Author(s):  
Abdulsalam A. Al-Tamimi ◽  
Chris Peach ◽  
Paulo Rui Fernandes ◽  
Akos Cseke ◽  
Paulo J.D.S. Bartolo
Keyword(s):  
Topology Optimization ◽  
Stress Shielding ◽  
Shielding Effect ◽  
Orthopedic Applications

Development of computational Tibia model to investigate stress shielding effect at healing stages

2018 ◽  
Vol 5 (5) ◽  
pp. 13267-13275 ◽  
Author(s):  
Emon Barua ◽  
Saurav Das ◽  
Ashish B. Deoghare
Keyword(s):  
Stress Shielding ◽  
Shielding Effect

scholarly journals Design and Performance Evaluation of Porous Titanium Alloy Structures for Bone Implantation

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Jianping Shi ◽  
Huixin Liang ◽  
Jie Jiang ◽  
Wenlai Tang ◽  
Jiquan Yang
Keyword(s):  
Elastic Modulus ◽  
Stress Shielding ◽  
Porous Titanium ◽  
Shielding Effect ◽  
Host Bone ◽  
Test Results ◽  
Porous Implant ◽  
Biomechanical Simulation ◽  
Design And Manufacturing ◽  
And Performance

Implant parts prepared by traditional design and manufacturing methods generally have problems of high stiffness and heavy self-weight, which may cause stress shielding effect between the implanted part and the host bone, and eventually cause loosening of the implanted part. Based on the implicit surface function equations, several porous implant models with controlled pore structure were designed. By adjusting the parameters, the apparent elastic modulus of the porous implant model can be regulated. The biomechanical simulation experiment was performed using CAE software to simulate the stress and elastic modulus of the designed models. The experimental results show that the apparent elastic modulus of the porous structure scaffold is close to that of the bone tissue, which can effectively reduce the stress shielding effect. In addition, the osseointegration status between the implant and the host bone was analyzed by implant experiment. The pushout test results show that the designed porous structures have a good osseointegration effect.

Preliminary Study of Manufacturing Technique Using Three Dimensions Stain Steel Braid for Bone Scaffold

2012 ◽  
Vol 184-185 ◽  
pp. 1424-1427
Author(s):  
Jia Horng Lin ◽  
Ching Wen Lin ◽  
Yueh Sheng Chen ◽  
Chien Lin Huang ◽  
Wen Cheng Chen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Stress Shielding ◽  
Three Dimensions ◽  
304 Stainless Steel ◽  
Shielding Effect ◽  
Metallic Materials ◽  
Bone Scaffold ◽  
Artificial Bone ◽  
Stereo Microscope

Nowadays, as rising research on biomaterials, the artificial bone scaffold has become the most important part of the study. Moreover, metallic materials have been applied on the artificial bone scaffold; but its high rigidity causes the stress shielding effect in bones. To improve the disadvantages of metallic materials and pursue their better mechanical properties, 304 stainless steel fibers have multi-layer braided into the 3D stainless-steel braid with porous structure and better mechanical properties, using braiding machine. In multi-layer braiding process, with the constant number of take-up gear and varying number of braid gear, the 3D stainless-steel braid was manufactured. Afterwards, its braiding structure and angle were observed by stereo microscope. Also, the optimal braiding parameters can be acquired from tensile strength test.

EFFECTS OF DIFFERENT LATERAL FEMORAL WALL THICKNESSES IN INTERTROCHANTERIC HIP FRACTURE TREATED WITH DYNAMIC HIP SCREW

2019 ◽  
Vol 19 (02) ◽  
pp. 1940022
Author(s):  
CHENG-CHI WANG ◽  
CHENG-HUNG LEE ◽  
KUN-HUI CHEN ◽  
CHIEN-CHOU PAN ◽  
KUO-CHIH SU
Keyword(s):  
Hip Fractures ◽  
Stress Shielding ◽  
Simulation Models ◽  
Lateral Wall ◽  
Dynamic Hip Screw ◽  
Shielding Effect ◽  
Element Analysis ◽  
Lag Screw ◽  
Hip Screw ◽  
Biomechanical Effect

Dynamic hip screw (DHS) is commonly used for stable-type intertrochanteric hip fractures. The importance of lateral femoral wall has been mentioned while treating intertrochanteric hip fractures with DHS. The aim of this study was mainly to investigate the biomechanical effect of different thickness of lateral femoral wall using finite element analysis (FEA). This study constructed FEA simulation models for five different lateral femoral wall thicknesses, and demonstrated the stress distribution on the femoral bone, the cortical screws, the cancellous bone around the lag screw, and the lag screw. The main results showed that when the DHS is implanted, less stress will be distributed at the implantation site on the femur due to the stress-shielding effect. The stress on the cortical screws will be greater at the junction of the cortical screws and the cortical bone. Intertrochanteric hip fractures with a thinner lateral wall thickness may cause higher stress on the femur after DHS is implanted.

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