Modeling and Validation of Additively Manufactured Porous Nitinol Implants

2014 ◽  
Author(s):  
Rasool Rahmanian ◽  
Mohsen Taheri Andani ◽  
Jason Walker ◽  
Christoph Habeland ◽  
Mohammad Elahinia ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Bone Loss ◽  
Test Results ◽  
Bone Implants ◽  
Bone Implant ◽  
Long Term Stability ◽  
Implant Integration ◽  
Manufacturing Techniques ◽  
Materials Used

Bone implants are long term solutions for bone loss. Currently, two issues have been identified as reducing the long term stability of bone implants. The first issue is stiffness mismatch between the implant and the surrounding bony structure. The current materials used for manufacturing bone implants are much stiffer than the surrounding host bone. The second issue concerns bone-implant integration; the fact is that the bone needs an appropriate surface on which to attach and accept or deliver a load. Additive manufacturing techniques using Nitinol may provide the ability to fabricate bone implants with predetermined pore size and stiffness. This work brings the concept of stiffness tailoring to reality, taking advantage of additive manufacturing technique to fabricate engineering porosity to modify the stiffness. Based on the simulation and test results, it is shown that implants can be made with the stiffness in the range of the stiffness of the bone. The same capabilities can be used to affect a rough surface onto which bone is more likely to attach.

Long-Term Stability of the Oxidized Hole-Transporting Materials used in Perovskite Solar Cells

2018 ◽  
Vol 24 (39) ◽  
pp. 9910-9918 ◽  
Author(s):  
Ernestas Kasparavicius ◽  
Artiom Magomedov ◽  
Tadas Malinauskas ◽  
Vytautas Getautis
Keyword(s):  
Solar Cells ◽  
Perovskite Solar Cells ◽  
Term Stability ◽  
Long Term Stability ◽  
Hole Transporting ◽  
Materials Used ◽  
Hole Transporting Materials

scholarly journals Mechanical properties comparison of Ti6Al4V produced by different technologies under static load conditions

2019 ◽  
Vol 290 ◽  
pp. 08010
Author(s):  
Karolina Karolewska ◽  
Bogdan Ligaj
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Selective Laser Sintering ◽  
Laser Sintering ◽  
Ti6al4v Alloy ◽  
Direct Metal Laser Sintering ◽  
Static Tests ◽  
Rolling Method ◽  
Manufacturing Techniques ◽  
Materials Used

The most commonly used technology among the additive manufacturing is Direct Metal Laser Sintering (DMLS). This process is based on selective laser sintering (SLS). The method gained its popularity due to the possibility of producing metal parts of any geometry, which would be difficult or impossible to obtain by the use of conventional manufacturing techniques. Materials used in the elements manufacturing process are: titanium alloys (e.g. Ti6Al4V), aluminium alloy AlSi10Mg, etc. Elements printed from Ti6Al4V titanium alloy find their application in many industries. Details produced by additive technology are often used in medicine as skeletal, and dental implants. Another example of the DMLS elements use is the aerospace industry. In this area, the additive manufacturing technology produces, i.a. parts of turbines. In addition to the aerospace and medical industries, DMLS technology is also used in motorsport for exhaust pipes or the gearbox parts. The research objects are samples for static tests. These samples were made of Ti6Al4V alloy by the DMLS method and the rolling method from a drawn rod. The aim of the paper is the mechanical properties comparative analysis of the Ti6Al4V alloy produced by the DMLS method under static loading conditions and microstructure analysis of this material.

Long-term stability study of drug products and out-of-specification test results

2011 ◽  
Vol 16 (12) ◽  
pp. 615-622 ◽  
Author(s):  
Ilya Kuselman ◽  
Ilana Schumacher ◽  
Francesca Pennecchi ◽  
Cathy Burns ◽  
Aleš Fajgelj ◽  
...  
Keyword(s):  
Stability Study ◽  
Test Results ◽  
Specification Test ◽  
Term Stability ◽  
Drug Products ◽  
Long Term Stability

scholarly journals Additive Manufacturing Technologies: An Overview about 3D Printing Methods and Future Prospects

Complexity ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-30 ◽  
Author(s):  
Mariano Jiménez ◽  
Luis Romero ◽  
Iris A. Domínguez ◽  
María del Mar Espinosa ◽  
Manuel Domínguez
Keyword(s):  
Additive Manufacturing ◽  
Sustainable Manufacturing ◽  
Academic Field ◽  
Geometrical Complexity ◽  
Production Run ◽  
Professional Field ◽  
Manufacturing Techniques ◽  
Materials Used ◽  
Lower Tool ◽  
Manufacturing Technologies

The use of conventional manufacturing methods is mainly limited by the size of the production run and the geometrical complexity of the component, and as a result we are occasionally forced to use processes and tools that increase the final cost of the element being produced. Additive manufacturing techniques provide major competitive advantages due to the fact that they adapt to the geometrical complexity and customised design of the part to be manufactured. The following may also be achieved according to field of application: lighter weight products, multimaterial products, ergonomic products, efficient short production runs, fewer assembly errors and, therefore, lower associated costs, lower tool investment costs, a combination of different manufacturing processes, an optimised use of materials, and a more sustainable manufacturing process. Additive manufacturing is seen as being one of the major revolutionary industrial processes of the next few years. Additive manufacturing has several alternatives ranging from simple RepRap machines to complex fused metal deposition systems. This paper will expand upon the structural design of the machines, their history, classification, the alternatives existing today, materials used and their characteristics, the technology limitations, and also the prospects that are opening up for different technologies both in the professional field of innovation and the academic field of research. It is important to say that the choice of technology is directly dependent on the particular application being planned: first the application and then the technology.

Improve Stability of Dicalcium Silicate/Zirconia Composite Coatings by Post-Spraying Heat Treatment

2005 ◽  
Vol 107 ◽  
pp. 141-144 ◽  
Author(s):  
Youtao Xie ◽  
Paul K. Chu ◽  
Xuan Yong Liu ◽  
Chuan Xian Ding
Keyword(s):  
Heat Treatment ◽  
Composite Coatings ◽  
Immersion Test ◽  
Dicalcium Silicate ◽  
Test Results ◽  
Long Term Stability ◽  
The Stability ◽  
Plasma Sprayed ◽  
Sprayed Coatings

The long-term stability of plasma-sprayed dicalcium silicate (C2S) composite coatings is determined by the phase composition, crystallinity, and other properties. Zirconia reinforcement and post-spraying heat treatment are applied to C2S coatings simultaneously in this work. The stability of the coating increases evidently by reinforcement with 70wt% zirconia and heat treatment at 800oC for 4 hours. SEM reveals that the smooth glassy surface of the as-sprayed coatings is replaced by randomly dispersed crystals. Tris-HCl immersion test results show that the dissolution rate of the composite coatings decreases after the heat treatment.

DYNA Numerical Experiment on Long-Term Stability of Strip Pillar in Deep Mine

2011 ◽  
Vol 217-218 ◽  
pp. 1520-1524
Author(s):  
Chun Qiu Wang ◽  
Shi Bin Gu ◽  
Zhong Ju Wei ◽  
Bo Li ◽  
Shao Jie Chen
Keyword(s):  
Stable State ◽  
Support Effect ◽  
Test Results ◽  
Deep Mine ◽  
Long Term Stability ◽  
Creep Stress ◽  
Working Face ◽  
Stress And Deformation ◽  
Overlying Strata

The creep test of the No. 3 coal seam of Daizhuang Coal Mine is carried. Based on the experiment results, the creep support effect of deep pillar is analyzed with LS-DYNA. The results show that the circumferential initial creep stress of the tested coal is 3.061MPa and the circumferential initial creep stress is far below the axial initial creep stress which is 7.020MPa. In addition, the creep strength is 9.3266MPa and the creep coefficient is 0.6472. According to the test results, the creep support effect of deep strip pillar can be simulated excellently with LS-DYNA. Stress and deformation in simulated strip pillar show evident rheology. Many changes will take place in the stable situation of pillar after the working face mining. Under the effect of the overlying strata, this pillar turns into steady creep state after 15~16 months, then the pillar is able to maintain long-term stable state.

scholarly journals Occlusal Principles and Considerations for Implants: An Overview

2014 ◽  
Vol 1 (2) ◽  
pp. 17
Author(s):  
Siddhartha Paliwal ◽  
Deepesh Saxena ◽  
Rohit Mittal ◽  
Shivangi Chaudhary
Keyword(s):  
Risk Factors ◽  
Periodontal Ligament ◽  
Support Design ◽  
Bone Implant ◽  
Long Term Stability ◽  
Physiological Limits ◽  
Stomatognathic System ◽  
Force Direction ◽  
Natural Tooth

The treatment planning phase of implant prostheses is dependent on the restorative dentist's knowledge and experience in prosthetic dentistry. Clinically, for implant prostheses, natural occlusal concepts can be applied. However, a natural tooth has a support design i.e. periodontal ligament that reduces the forces to the surrounding crest of bone compared to the same region around an implant. If biomechanical stresses are likely to increase in a clinical condition, occlusal mechanisms to decrease the stresses should be implemented by the dentist and an occlusal scheme should be developed that minimizes risk factors and allows the restoration to function in harmony with the rest of the stomatognathic system. Implant-protected occlusion is proposed as a way to overcome mechanical stresses and strain from the oral musculature and occlusion, by avoiding initial and long-term loss of crestal bone surrounding implant fixtures. Implant-protected occlusion can be accomplished by factors like decreasing the width of the occlusal table, increasing the surface area of implants, reducing the magnification of the force and improving the force direction. The dentist can minimize overload on bone-implant interfaces and implant prostheses, maintain an implant load within the physiological limits of individualized occlusion, and ultimately provide long-term stability of implants and implant prostheses by following above mentioned factors.

Improved long-term bone-implant integration Experiments in transgenic mice overexpressing bovine growth hormone

1997 ◽  
Vol 68 (4) ◽  
pp. 344-348 ◽  
Author(s):  
Per H Morberg ◽  
Olle G P Isaksson ◽  
Carina B Johansson ◽  
Jonas Sandstedt ◽  
Jan F Törnell
Keyword(s):  
Growth Hormone ◽  
Transgenic Mice ◽  
Bovine Growth Hormone ◽  
Bone Implant ◽  
Implant Integration

scholarly journals Current Status and Perspectives on Wire and Arc Additive Manufacturing (WAAM)

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1121 ◽  
Author(s):  
Tiago A. Rodrigues ◽  
V. Duarte ◽  
R.M. Miranda ◽  
Telmo G. Santos ◽  
J.P. Oliveira
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Three Dimensional ◽  
Current Status ◽  
Powder Bed ◽  
Significant Research ◽  
Manufacturing Techniques ◽  
Materials Used ◽  
Metallic Parts ◽  
General Perspective

Additive manufacturing has revolutionized the manufacturing paradigm in recent years due to the possibility of creating complex shaped three-dimensional parts which can be difficult or impossible to obtain by conventional manufacturing processes. Among the different additive manufacturing techniques, wire and arc additive manufacturing (WAAM) is suitable to produce large metallic parts owing to the high deposition rates achieved, which are significantly larger than powder-bed techniques, for example. The interest in WAAM is steadily increasing, and consequently, significant research efforts are underway. This review paper aims to provide an overview of the most significant achievements in WAAM, highlighting process developments and variants to control the microstructure, mechanical properties, and defect generation in the as-built parts; the most relevant engineering materials used; the main deposition strategies adopted to minimize residual stresses and the effect of post-processing heat treatments to improve the mechanical properties of the parts. An important aspect that still hinders this technology is certification and nondestructive testing of the parts, and this is discussed. Finally, a general perspective of future advancements is presented.

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