scholarly journals Biomechanical Assessment of Design Parameters on a Self-Developed 3D-Printed Titanium-Alloy Reconstruction/Prosthetic Implant for Mandibular Segmental Osteotomy Defect

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 597
Author(s):  
Sheng-Ni Huang ◽  
Ming-You Shie ◽  
Yen-Wen Shen ◽  
Jui-Ting Hsu ◽  
Heng-Li Huang ◽  
...  
Keyword(s):  
Oral Cancer ◽  
Cortical Bone ◽  
Three Dimensional ◽  
Design Parameters ◽  
Mandibular Bone ◽  
Biomechanical Assessment ◽  
Metal Printing ◽  
Facial Area ◽  
3D Metal Printing ◽  
3D Printed

Patients with oral cancer often have to undergo the surgery for mandibular excision. Once the bone in the cancerous area is removed, not only the facial area but also chewing function of the patient is needed to be repaired by clinicians. In recent years, the rapid growth of three-dimensional (3D) metal printing technology has meant that higher-quality facial reconstructions are now possible, which could even restore chewing function. This study developed 3D-printed titanium (Ti)-alloy reconstruction implant for a prosthesis designed for mandibular segmental osteotomy defects, and 3D finite element (FE) analysis was conducted to evaluate its biomechanical performance. The analyzed parameters in the FE models were as follows: (1) two prosthesis designs, namely a prosthesis retaining the residual mandibular bone (for patients with mild oral cancer) and a prosthesis with complete mandibular resection (for patients with severe oral cancer); (2) two lengths of prosthesis, namely 20 and 25 mm; and (3) three thicknesses of prosthesis, namely 0.8, 1, and 1.5 mm. A 45° lateral bite force (100 N) was applied to the top of the prosthesis as the loading condition. The results revealed that for the two prosthesis designs, the prosthesis retaining the residual mandibular bone showed higher stress on the prosthesis and cortical bone compared with the prosthesis with complete mandibular resection. Regarding the two prosthesis lengths, no fixed trend of prosthesis stress was found, but stress in the cortical bone was relatively high for a prosthesis length of 20 mm compared with that of 25 mm. For the three prosthesis thicknesses, as the thickness of the prosthesis decreased, the stress in the prosthesis decreased but the stress in the cortical bone increased. These findings require confirmation in future clinical investigations.

scholarly journals Modeling of Dental Implant Osseointegration Progress by Three-Dimensional Finite Element Method

2020 ◽  
Vol 10 (16) ◽  
pp. 5561
Author(s):  
Iulia Roatesi ◽  
Simona Roatesi
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stress Concentration ◽  
Cortical Bone ◽  
Three Dimensional ◽  
Biomechanical Properties ◽  
Biomechanical Assessment ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Element Method

As osseointegration is a time-dependent process, biomechanical assessment is thought to determine whether a fibrous encapsulation or a bone covering will develop around an implant, according to the stress in the implant and surrounding bone. This study proposes a model for stress evaluation by finite element method (FEM) during the osseointegration progress, the main factor implied in implant success or failure. The loadings due to masticatory forces generate stress concentration and consequently, an adequate risk concerning the implant stability should be assessed. An accurate FEM model is used to calculate the stress and displacement in the whole implant–bone system during the osseointegration progress. This process is simulated by taking into account the gradual increase in the damaged biomechanical properties of the cortical bone. The results reveal that as the implant osseointegration occurs gradually, the bone stiffness from the peri-implant area increases gradually, such that in the end (healing) we observed that the cortical bone begins to take over the bending loading. In addition, the displacements decrease as the osseointegration gradually occurs and the cortical bone stress reaches higher values, which are placed in the mandibular ridge. The FEM is suitable to model the osseointegration progress, offering valuable information concerning the stress concentration zones in the implant–bone system and consequently, the risk evaluation, both for pre- and post-osseointegration.

Design and Analysis of a Novel Lightweight, Energy Economic Powered Knee Orthotic Device

2019 ◽  
Vol 13 (3) ◽  
Author(s):  
Saikat Sahoo ◽  
Aditya Jain ◽  
Dilip Kumar Pratihar
Keyword(s):  
Knee Joint ◽  
Power Consumption ◽  
Three Dimensional ◽  
Fast Response ◽  
Design Parameters ◽  
Angular Deviation ◽  
Natural Behavior ◽  
Orthotic Device ◽  
3D Printed ◽  
Novel Design

The task of a powered knee orthotic device (PKOD) is to assist the knee joint so that its natural behavior can be restored. The key features of a PKOD that may help to regain such characteristics are low power consumption, fast response, compactness, and lightweight. This study proposes a novel design of PKOD, where we have focused on the betterment of the mentioned features with the help of a new mechanism, namely a four-bar controlled compliance actuator (FCCA). In FCCA, instead of using the widely used screw transmission mechanism, a four-bar mechanism is used to modify the joint's angular deviation and stiffness. The main advantages of using FCCA over other existing mechanisms are to reduce the power consumption by amplification of input motor torque and to achieve a faster response at the same time, and these are achieved by utilizing a simple four-bar mechanism. In the proposed design, FCCA controls both the stiffness of the artificial knee joint using a compliance mechanism as well as knee flexion with the help of a pulley arrangement. A three-dimensional (3D)-printed prototype of the proposed design has been developed, after optimizing the inherent design parameters. Simulation and experimental analysis are carried out in order to justify the performance of the proposed PKOD. The results have shown strong agreement with that obtained using analytical study and optimization. Moreover, the torque amplification is achieved, as desired.

3D-printed programmable tensegrity for soft robotics

2020 ◽  
Vol 5 (45) ◽  
pp. eaay9024
Author(s):  
Hajun Lee ◽  
Yeonwoo Jang ◽  
Jun Kyu Choe ◽  
Suwoo Lee ◽  
Hyeonseo Song ◽  
...  
Keyword(s):  
Smart Materials ◽  
Structural Integrity ◽  
Three Dimensional ◽  
Structural Complexity ◽  
System Level ◽  
Design Parameters ◽  
Tensegrity Structures ◽  
Tensegrity Systems ◽  
3D Printed ◽  
3D Shapes

Tensegrity structures provide both structural integrity and flexibility through the combination of stiff struts and a network of flexible tendons. These structures exhibit useful properties: high stiffness-to-mass ratio, controllability, reliability, structural flexibility, and large deployment. The integration of smart materials into tensegrity structures would provide additional functionality and may improve existing properties. However, manufacturing approaches that generate multimaterial parts with intricate three-dimensional (3D) shapes suitable for such tensegrities are rare. Furthermore, the structural complexity of tensegrity systems fabricated through conventional means is generally limited because these systems often require manual assembly. Here, we report a simple approach to fabricate tensegrity structures made of smart materials using 3D printing combined with sacrificial molding. Tensegrity structures consisting of monolithic tendon networks based on smart materials supported by struts could be realized without an additional post-assembly process using our approach. By printing tensegrity with coordinated soft and stiff elements, we could use design parameters (such as geometry, topology, density, coordination number, and complexity) to program system-level mechanics in a soft structure. Last, we demonstrated a tensegrity robot capable of walking in any direction and several tensegrity actuators by leveraging smart tendons with magnetic functionality and the programmed mechanics of tensegrity structures. The physical realization of complex tensegrity metamaterials with programmable mechanical components can pave the way toward more algorithmic designs of 3D soft machines.

A Comparative Study of Surface Cleaning Treatments for 3D Printed Medical Implants

2017 ◽  
Author(s):  
Lucy Guo ◽  
Zhiqiang Xie ◽  
Hong Yao ◽  
Ying Wang
Keyword(s):  
Additive Manufacturing ◽  
Comparative Study ◽  
Surface Cleaning ◽  
Valuable Insight ◽  
Medical Implants ◽  
Post Process ◽  
Metal Printing ◽  
Weak Points ◽  
3D Metal Printing ◽  
3D Printed

In the field of Additive Manufacturing (AM), one of the major applications of laser-based 3D metal printing is the creation of custom implants for medical purposes. However, a significant challenge in the manufacturing of implants using Selective Laser Melting (SLM) is the formation of partially melted particles on the surface of medical implants. These particles result in a multitude of issues including plurality of structurally weak points on the designed implants, obstruction of important design features, and possibility of dislodgement over the service life span, thereby posing a threat to the recipient. To address the above challenges, it is imperative to develop a simple but effective surface cleaning method to remove partially melted particles from the surface without damage to the designed medical implants. In this work, a comparative study was conducted to investigate the effect of both chemical and electro-plasma based cleaning processes on the removal of partially melted particles from the surfaces of 3D printed Ti-6Al-4V medical screw implants. These techniques include chemically polishing implants with HF-HNO3 acid solutions and using an electro-plasma based cleaning process. With the field of additive manufacturing rapidly expanding, this work offers valuable insight on proper post-process treatment of 3D printed parts for future medical purposes in biomedical fields.

Use of Three-dimensional Printing in the Development of Optimal Cardiac CT Scanning Protocols

2020 ◽  
Vol 16 (8) ◽  
pp. 967-977
Author(s):  
Zhonghua Sun
Keyword(s):  
Cardiovascular Disease ◽  
Cardiac Computed Tomography ◽  
Three Dimensional ◽  
Ct Scanning ◽  
Aortic Diseases ◽  
Clinical Value ◽  
Three Dimensional Printing ◽  
Doctor Patient Communication ◽  
Medical Education And Training ◽  
3D Printed

Three-dimensional (3D) printing is increasingly used in medical applications with most of the studies focusing on its applications in medical education and training, pre-surgical planning and simulation, and doctor-patient communication. An emerging area of utilising 3D printed models lies in the development of cardiac computed tomography (CT) protocols for visualisation and detection of cardiovascular disease. Specifically, 3D printed heart and cardiovascular models have shown potential value in the evaluation of coronary plaques and coronary stents, aortic diseases and detection of pulmonary embolism. This review article provides an overview of the clinical value of 3D printed models in these areas with regard to the development of optimal CT scanning protocols for both diagnostic evaluation of cardiovascular disease and reduction of radiation dose. The expected outcomes are to encourage further research towards this direction.

scholarly journals A Novel Approach for a Faster Prototyping of Winter Sport Equipment Using Digital Image Correlation and 3D Printing

Proceedings ◽  
2020 ◽  
Vol 49 (1) ◽  
pp. 125
Author(s):  
Martino Colonna ◽  
Benno Zingerle ◽  
Maria Federica Parisi ◽  
Claudio Gioia ◽  
Alessandro Speranzoni ◽  
...  
Keyword(s):  
3D Printing ◽  
Digital Image Correlation ◽  
Digital Image ◽  
Sport Activity ◽  
Image Correlation ◽  
Topological Optimization ◽  
Design Parameters ◽  
Sport Equipment ◽  
Novel Approach ◽  
3D Printed

The optimization of sport equipment parts requires considerable time and high costs due to the high complexity of the development process. For this reason, we have developed a novel approach to decrease the cost and time for the optimization of the design, which consists of producing a first prototype by 3D printing, applying the forces that normally acts during the sport activity using a test bench, and then measuring the local deformations using 3D digital image correlation (DIC). The design parameters are then modified by topological optimization and then DIC is performed again on the new 3D-printed modified part. The DIC analysis of 3D-printed parts has shown a good agreement with that of the injection-molded ones. The deformation measured with DIC are also well correlated with those provided by finite element method (FEM) analysis, and therefore DIC analysis proves to be a powerful tool to validate FEM models.

Investigation of the Static Behavior and Failure Mechanisms of a 3D Printed Bio-Based Sandwich with Auxetic Core

2020 ◽  
Vol 12 (05) ◽  
pp. 2050051
Author(s):  
Khawla Essassi ◽  
Jean-Luc Rebiere ◽  
Abderrahim El Mahi ◽  
Mohamed Amine Ben Souf ◽  
Anas Bouguecha ◽  
...  
Keyword(s):  
Failure Mechanisms ◽  
Three Dimensional ◽  
Acoustic Emissions ◽  
Shear Stiffness ◽  
Tensile Tests ◽  
Sandwich Composite ◽  
Static Behavior ◽  
Flax Fibers ◽  
Data Points ◽  
3D Printed

In this research contribution, the static behavior and failure mechanisms are developed for a three-dimensional (3D) printed dogbone, auxetic structure and sandwich composite using acoustic emissions (AEs). The skins, core and whole sandwich are manufactured using the same bio-based material which is polylactic acid reinforced with micro-flax fibers. Tensile tests are conducted on the skins and the core while bending tests are conducted on the sandwich composite. Those tests are carried out on four different auxetic densities in order to investigate their effect on the mechanical and damage properties of the materials. To monitor the invisible damage and damage propagation, a highly sensitive AE testing method is used. It is found that the sandwich with high core density displays advanced mechanical properties in terms of bending stiffness, shear stiffness, facing bending stress and core shear stress. In addition, the AE data points during testing present an amplitude range of 40–85[Formula: see text]dB that characterizes visible and invisible damage up to failure.

Design and optimization of bump (compression surface) for diverterless supersonic inlet

2021 ◽  
pp. 095441002110029
Author(s):  
Irsalan Arif ◽  
Hassan Iftikhar ◽  
Ali Javed
Keyword(s):  
Fitness Function ◽  
Supersonic Jet ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Least Square ◽  
Pressure Recovery ◽  
Design Parameters ◽  
Inlet System ◽  
Design And Optimization ◽  
Supersonic Inlet

In this article design and optimization scheme of a three-dimensional bump surface for a supersonic aircraft is presented. A baseline bump and inlet duct with forward cowl lip is initially modeled in accordance with an existing bump configuration on a supersonic jet aircraft. Various design parameters for bump surface of diverterless supersonic inlet systems are identified, and design space is established using sensitivity analysis to identify the uncertainty associated with each design parameter by the one-factor-at-a-time approach. Subsequently, the designed configurations are selected by performing a three-level design of experiments using the Box–Behnken method and the numerical simulations. Surrogate modeling is carried out by the least square regression method to identify the fitness function, and optimization is performed using genetic algorithm based on pressure recovery as the objective function. The resultant optimized bump configuration demonstrates significant improvement in pressure recovery and flow characteristics as compared to baseline configuration at both supersonic and subsonic flow conditions and at design and off-design conditions. The proposed design and optimization methodology can be applied for optimizing the bump surface design of any diverterless supersonic inlet system for maximizing the intake performance.

scholarly journals Midface Reconstruction: Planning and Outcome

2020 ◽  
Vol 53 (03) ◽  
pp. 324-334
Author(s):  
Gautam Biswas
Keyword(s):  
Digital Imaging ◽  
3D Structure ◽  
Three Dimensional ◽  
The Past ◽  
Complex Anatomy ◽  
Osseointegrated Implants ◽  
Low Profile ◽  
3D Printed ◽  
Midface Reconstruction ◽  
Reconstruction Planning

Abstract Reconstruction of the complex anatomy and aesthetics of the midface is often a challenge. A careful understanding of this three-dimensional (3D) structure is necessary. Anticipating the extent of excision and its planning following oncological resections is critical.In the past over two decades, with the advances in microsurgical procedures, contributions toward the reconstruction of this area have generated interest. Planning using digital imaging, 3D printed models, osseointegrated implants, and low-profile plates, has favorably impacted the outcome. However, there are still controversies in the management: to use single composite tissues versus multiple tissues; implants versus autografts; vascularized versus nonvascularized bone; prosthesis versus reconstruction.This article explores the present available options in maxillary reconstruction and outlines the approach in the management garnered from past publications and experiences.

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