scholarly journals Mechanical property of octahedron Ti6Al4V fabricated by selective laser melting

2021 ◽  
Vol 60 (1) ◽  
pp. 894-911
Author(s):  
Yun Zhai ◽  
Sibo He ◽  
Lei Lei ◽  
Tianmin Guan
Keyword(s):  
Mechanical Property ◽  
Elastic Modulus ◽  
Selective Laser Melting ◽  
Mechanical Performance ◽  
Lattice Structure ◽  
Stress Shielding ◽  
Human Bone ◽  
Shielding Effect ◽  
Basic Unit ◽  
Laser Melting

Abstract The stress shielding effect is a critical issue for implanted prosthesis due to the difference in elastic modulus between the implanted material and the human bone. The adjustment of the elastic modulus of implants by modification of the lattice structure is the key to the research in the field of implanted prosthesis. Our work focuses on the basic unit structure of octahedron Ti6Al4V. The equivalent elastic modulus and equivalent density of porous structure are optimized according to the mechanical properties of human bone tissue by adjusting the edge diameter and side length of octahedral lattice. Macroscopic long-range ordered arrangement of lattice structures is fabricated by selective laser melting (SLM) technology. Finite element simulation is performed to calculate the mechanical property of octahedron Ti6Al4V. Scanning electronic microscopy is applied to observe the microstructure of octahedron alloy and its cross section morphology of fracture. Standard compression test is performed for the stress–strain behavior of the specimen. Our results show that the octahedral lattice with the edge diameter of 0.4 mm and unit cell length of 1.5 mm has the best mechanical property which is close to the human bone. The value of equivalent elastic modulus increases with the increase in the edge diameter. The SLM technology proves to be an effective processing way for the fabrication of complex microstructures with porosity. In addition, the specimen exhibits isotropic mechanical performance and homogeneity which significantly meet the requirement of implanted prosthetic medical environment.

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.

scholarly journals A Further Analysis on Ti6Al4V Lattice Structures Manufactured by Selective Laser Melting

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Saverio Maietta ◽  
Antonio Gloria ◽  
Giovanni Improta ◽  
Maria Richetta ◽  
Roberto De Santis ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mass Transport ◽  
Selective Laser Melting ◽  
Mechanical Performance ◽  
Stress Shielding ◽  
Lattice Structures ◽  
Laser Melting ◽  
Tissue Ingrowth ◽  
Architectural Features ◽  
Bone Atrophy

Mechanical and architectural features play an important role in designing biomedical devices. The use of materials (i.e., Ti6Al4V) with Young’s modulus higher than those of natural tissues generally cause stress shielding effects, bone atrophy, and implant loosening. However, porous devices may be designed to reduce the implant stiffness and, consequently, to improve its stability by promoting tissue ingrowth. If porosity increases, mass transport properties, which are crucial for cell behavior and tissue ingrowth, increase, whereas mechanical properties decrease. As reported in the literature, it is always possible to tailor mass transport and mechanical properties of additively manufactured structures by varying the architectural features, as well as pore shape and size. Even though many studies have already been made on different porous structures with controlled morphology, the aim of current study was to provide only a further analysis on Ti6Al4V lattice structures manufactured by selective laser melting. Experimental and theoretical analyses also demonstrated the possibility to vary the architectural features, pore size, and geometry, without dramatically altering the mechanical performance of the structure.

Mechanical performance of a node reinforced body-centred cubic lattice structure manufactured via selective laser melting

2020 ◽  
Vol 189 ◽  
pp. 95-100
Author(s):  
Yingang Liu ◽  
Jingqi Zhang ◽  
Xiaojun Gu ◽  
Ying Zhou ◽  
Yu Yin ◽  
...  
Keyword(s):  
Selective Laser Melting ◽  
Mechanical Performance ◽  
Lattice Structure ◽  
Laser Melting ◽  
Cubic Lattice

Microstructure and mechanical performance of ODS superalloys manufactured by selective laser melting

2021 ◽  
Vol 144 ◽  
pp. 107423
Author(s):  
Qing-song Song ◽  
Ying Zhang ◽  
Yun-feng Wei ◽  
Xin-yi Zhou ◽  
Yi-fu Shen ◽  
...  
Keyword(s):  
Selective Laser Melting ◽  
Mechanical Performance ◽  
Laser Melting

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.

Selective Laser Melting of Ti42Nb Composite Powder and the Effect of Laser Re-Melting

2019 ◽  
Vol 801 ◽  
pp. 270-275 ◽  
Author(s):  
Sheng Huang ◽  
Swee Leong Sing ◽  
Wai Yee Yeong
Keyword(s):  
Selective Laser Melting ◽  
Composite Powder ◽  
Stress Shielding ◽  
Alloyed Powder ◽  
Laser Melting ◽  
Scanning Strategy ◽  
Implant Materials ◽  
Bio Compatibility ◽  
Alloy Systems

Ti-Nb based alloys have the potential to be used as structural implant materials due to their excellent bio-compatibility and ability to reduce stress shielding. The idea to additively manufacture Ti-Nb based alloys using selective laser melting (SLM) technology can further improve the resultant implant quality. However, the lack of economically sound and readily available pre-alloyed powder has pushed for the usage of composite powder as a means to hasten research pace in fabricating new alloy systems via SLM. The usage of Ti-Nb composite powder can lead to several problems, particularly the issue of macro-segregation. Hence, this paper presents the potential of laser re-melting scanning strategy to address macro-segregation without sacrificing (or even improving) density of parts fabricated by SLM.

Influence of specimen size on the mechanical properties of microlattices obtained by selective laser melting

2019 ◽  
pp. 095440621986974
Author(s):  
Matteo Gavazzoni ◽  
Laura Boniotti ◽  
Stefano Foletti
Keyword(s):  
Elastic Modulus ◽  
Selective Laser Melting ◽  
Test Procedure ◽  
Specimen Size ◽  
The Body ◽  
Image Correlation ◽  
Good Prediction ◽  
Face Centered Cubic ◽  
Body Centered Cubic ◽  
Laser Melting

A detailed study of compression tests on lattice structures obtained by selective laser melting with AlSi7Mg powder is presented here. Two different cell topologies have been investigated: the body-centered cubic cell and the face centered cubic cell or 3D Warren structure. Specimens of different volume have been printed in order to investigate the effect of the size on the mechanical response and properties of the structure. Particular attention has been paid to the definition of the test procedure and the analysis of the data to properly characterize the microlattice. No remarkable effect of the specimen size has been found in terms of elastic modulus and yielding stress. On the contrary, the maximum stress and the failure mechanism are influenced by the size of the specimen; for the body-centered cubic cell, a detailed analysis has been performed through digital image correlation of the failure. Test results have been compared with the results of an elasto-plastic simulation performed on a single cell of lattice with periodic boundary conditions, showing a good prediction in terms of elastic modulus and yielding stress.

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