scholarly journals Design Data and Finite Element Analysis of 3D Printed Poly(ε-Caprolactone)-Based Lattice Scaffolds: Influence of Type of Unit Cell, Porosity, and Nozzle Diameter on the Mechanical Behavior

Eng ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 9-23
Author(s):  
Riccardo Sala ◽  
Stefano Regondi ◽  
Raffaele Pugliese
Keyword(s):  
Finite Element ◽  
Mechanical Behavior ◽  
Computer Aided Design ◽  
Unit Cell ◽  
Critical Parameters ◽  
Lattice Structures ◽  
Fused Filament Fabrication ◽  
Element Analysis ◽  
Custom Made ◽  
3D Printed

Material extrusion additive manufacturing (MEAM) is an advanced manufacturing method that produces parts via layer-wise addition of material. The potential of MEAM to prototype lattice structures is remarkable, but restrictions imposed by manufacturing processes lead to practical limits on the form and dimension of structures that can be produced. For this reason, such structures are mainly manufactured by selective laser melting. Here, the capabilities of fused filament fabrication (FFF) to produce custom-made lattice structures are explored by combining the 3D printing process, including computer-aided design (CAD), with the finite element method (FEM). First, we generated four types of 3D CAD scaffold models with different geometries (reticular, triangular, hexagonal, and wavy microstructures) and tunable unit cell sizes (1–5 mm), and then, we printed them using two nozzle diameters (i.e., 0.4 and 0.8 mm) in order to assess the printability limitation. The mechanical behavior of the above-mentioned lattice scaffolds was studied using FEM, combining compressive modulus (linear and nonlinear) and shear modulus. Using this approach, it was possible to print functional 3D polymer lattice structures with some discrepancies between nozzle diameters, which allowed us to elucidate critical parameters of printing in order to obtain printed that lattices (1) fully comply with FFF guidelines, (2) are capable of bearing different compressive loads, (3) possess tunable porosity, and (3) overcome surface quality and accuracy issues. In addition, these findings allowed us to develop 3D printed wrist brace orthosis made up of lattice structures, minimally invasive (4 mm of thick), lightweight (<20 g), and breathable (porosity >80%), to be used for the rehabilitation of patients with neuromuscular disease, rheumatoid arthritis, and beyond. Altogether, our findings addressed multiple challenges associated with the development of polymeric lattice scaffolds with FFF, offering a new tool for designing specific devices with tunable mechanical behavior and porosity.

Finite Element Analysis to Predict the Mechanical Behavior of Lattice Structures Made by Selective Laser Melting Technology

2014 ◽  
Vol 657 ◽  
pp. 231-235 ◽  
Author(s):  
Răzvan Păcurar ◽  
Ancuţa Păcurar ◽  
Anna Petrilak ◽  
Nicolae Bâlc
Keyword(s):  
Finite Element ◽  
Mechanical Behavior ◽  
Selective Laser Melting ◽  
Lattice Structure ◽  
Point Of View ◽  
Mechanical Resistance ◽  
Lattice Structures ◽  
Laser Melting ◽  
Element Analysis ◽  
Medical Implant

Within this article, there are presented a series of researches that are related to the field of customized medical implants made by Additive Manufacturing techniques, such as Selective Laser Melting (SLM) technology. Lattice structures are required in this case for a better osteointegration of the medical implant in the contact area of the bone. But the consequence of using such structures is important also by the mechanical resistance point of view. The shape and size of the cells that are connected within the lattice structure to be manufactured by SLM is critical in this case. There are also few limitations related to the possibilities and performances of the SLM equipment, as well. This is the reason why, several types of lattice structures were designed as having different geometric features, with the aim of analyzing by using finite element method, how the admissible stress and strain will be varied in these cases and what would be the optimum size and shape of the cells that confers the optimum mechanical behavior of lattice structures used within the SLM process of the customized medical implant manufactured from titanium-alloyed materials.

scholarly journals A comparative finite analysis of the mechanical behavior of ProTaper NEXT and WaveOne rotary files

2019 ◽  
Vol 43 (1) ◽  
Author(s):  
Nada Omar ◽  
Amira Galal Ismail ◽  
Manar Galal ◽  
Mohamed H. Zaazou ◽  
Mohamed Abdullah Mohamed
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Mechanical Behavior ◽  
Computer Aided Design ◽  
Software Package ◽  
Three Dimensional ◽  
Vertical Displacement ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Concentrated Load

Abstract Finite element analysis was used to evaluate the stress distribution, estimate the residual stresses, bending, and amount of displacement of two nickel-titanium instruments manufactured by the same M-wire technology but with different cross-section. Materials and methods Two brands of Ni-Ti instruments ProTaper NEXT (Dentsply Maillefer), and WaveOne (Dentsply Maillefer, Ballaigues, Switzerland) were scanned with stereomicroscope to produce a two-dimensional model for each file using computer-aided design programs (CAD) (SolidWorks software package), which then was converted into stereolithographic extension to be readable by programming software (MATLAB software) to produce three-dimensional models. The mathematical analysis of files was performed on SolidWorks software package. The mechanical behavior of the two files was analyzed numerically in a SolidWorks package to simulate and measure torsion, bending, and file displacement. Application of a shear moment (torsion) 2.5 N/mm moment of force was applied to the shaft in a clockwise direction, while the last 4 mm of the tip was rigidly constrained to evaluate the stress distribution on each file. As for Cantilever bending, a concentrated load of 1 N at the tip of the file with its shaft rigidly held in place was applied for the finite element models. The vertical displacement was measured and the von Mises stress distribution was evaluated. Results The WaveOne file showed higher torsional stresses accumulation than those accumulated in the ProTaper NEXT. While the ProTaper NEXT showed more bending and file displacement than those showed by WaveOne file. Conclusions The two files rotary models highlighted the different mechanical properties of the files although they share the same manufactured technology M-wire. The ProTaper NEXT showed less torsional stress accumulation and more bending properties.

scholarly journals Effects of Material Properties in Fabricating the Assistive Headrest Orthosis

2021 ◽  
Vol 11 (11) ◽  
pp. 123-129
Author(s):  
Mohd Hazwan Mohamed Norli ◽  
◽  
Madya Mastika Ahmad ◽  
Wan Nur Fatini W. Dagang ◽  
Mohd Hafiz Mohd Noh ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Computer Aided Design ◽  
Material Selection ◽  
Acrylonitrile Butadiene Styrene ◽  
Element Analysis ◽  
3D Printed ◽  
Process Computer ◽  
Aided Design ◽  
Butadiene Styrene

- These days, numerous decisions and efforts are contributing to cerebral palsy (CP) cases. Patient with spastic or dyskinetic CP has to survive independently, where most of the time is spent in a wheelchair. An extension headrest must be applied to maximize independence and functionality in the sitting position for routine activities. This study aims to investigate the effects of material selection in fabricating the 3D-printed adjustable headrest. Expected headrest users would be children (age seven to nine years old). There are five materials in this research: Polycarbonate (PC), Polylactic Acid (PLA), Acrylonitrile Butadiene Styrene (ABS), Polyamide (Nylon), and Polyethylene Terephthalate (PETG). In the designing process, Computer-Aided Design (CAD) software focuses on designing the structure and Finite Element Analysis (FEA) software to analyze various parts. To conclude this study, PLA is chosen as the best material based on the best stress, deformation, and safety factors. Keywords-- Adjustable headrest; finite element analysis; material selection; 3D printing

Utilizing Finite Element Analysis to Accurately Predict Fatigue Life of Autofrettaged Ultra High Pressure Components

2003 ◽  
Author(s):  
Weishun W. Ni ◽  
Christopher L. Tucker ◽  
Steve D. Able ◽  
Michael D. Mann
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
High Pressure ◽  
Fatigue Life ◽  
Computer Aided Design ◽  
Three Dimensional ◽  
Normal Operation ◽  
Critical Parameters ◽  
Element Analysis ◽  
Fatigue Life Analysis

Computer Aided Design and Finite Element Analysis packages that have been developed are capable of providing a relatively accurate fatigue life prediction. These software packages have made nonlinear analysis more reliable in forecasting a component’s fatigue life. A safe-life (in which the components are safe from failure during the estimated service life) can be predicted during the design process. The autofrettage technique has long been applied in high-pressure industries in order to extend the components’ life. The critical parameters that must be understood during a fatigue life analysis are material properties, including cyclic loading properties and stress excursion during the service cycle. In this paper, a three-dimensional finite element analysis of an autofrettaged manifold is presented. This assessment investigated an ANSI 316 stainless steel Tee-fitting, which was exposed to different cyclical loading conditions (two autofrettage conditions at a normal operation level). This was done in order to compare finite element analysis results to actual laboratory experimental results.

Integration of Design for Additive Manufacturing Constraints With Multimaterial Topology Optimization of Lattice Structures for Optimized Thermal and Mechanical Properties

2021 ◽  
Vol 144 (4) ◽  
Author(s):  
Vysakh Venugopal ◽  
Matthew McConaha ◽  
Sam Anand
Keyword(s):  
Thermal Conductivity ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Topology Optimization ◽  
Material Properties ◽  
Effective Properties ◽  
Lattice Structure ◽  
Unit Cell ◽  
Lattice Structures ◽  
Element Analysis

Abstract The design of multimaterial lattice structures with optimized elasticity tensor, coefficient of thermal expansion (CTE), and thermal conductivity is the main objective of the research presented in this article. In addition, the additive manufacturability of the lattice structure is addressed using a prismatic density filter to eliminate support structures, and an octant symmetry filter is used to design symmetric lattices. A density-based topology optimization model is formulated with a homogenization method and solved using a sequential linear programming method to obtain the desired unit cell geometry of the lattice structure. The optimized unit cell obtained has high mechanical stiffness, a low CTE, and low thermal conductivity. A finite element analysis is carried out on the optimized lattice structure and an equivalent cube of computed effective properties (with the same loading and boundary conditions) to validate the computed homogenized material properties. The results from the finite element analysis show that the methodology followed to generate the lattice structure is accurate. Such lattice structures with tailored material properties can be used in aerospace parts that are subjected to mechanical and thermal loads. The complex multimaterial geometry produced from the topology optimization routine presented here is intended explicitly for the manufacture of parts using the directed energy deposition process with multiple material deposition nozzles.

scholarly journals Manufacturing and Characterization of 3D Miniature Polymer Lattice Structures Using Fused Filament Fabrication

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 635 ◽  
Author(s):  
Rafael Guerra Silva ◽  
María Josefina Torres ◽  
Jorge Zahr Viñuela ◽  
Arístides González Zamora
Keyword(s):  
Additive Manufacturing ◽  
Good Control ◽  
Design Guidelines ◽  
Critical Parameters ◽  
Manufacturing Processes ◽  
Lattice Structures ◽  
Fused Filament Fabrication ◽  
Strut Thickness ◽  
Custom Made ◽  
Overhang Angle

The potential of additive manufacturing to produce architected lattice structures is remarkable, but restrictions imposed by manufacturing processes lead to practical limits on the form and dimension of structures that can be produced. In the present work, the capabilities of fused filament fabrication (FFF) to produce miniature lattices were explored, as they represent an inexpensive option for the production of polymer custom-made lattice structures. First, fused filament fabrication design guidelines were tested to assess their validity for miniature unit cells and lattice structures. The predictions were contrasted with the results of printing tests, showing some discrepancies between expected outcomes and resulting printed structures. It was possible to print functional 3D miniature open cell polymer lattice structures without support, even when some FFF guidelines were infringed, i.e., recommended minimum strut thickness and maximum overhang angle. Hence, a broad range of lattice structures with complex topologies are possible, beyond the cubic-type cell arrangements. Nevertheless, there are hard limits in 3D printing of miniature lattice structures. Strut thickness, length and orientation were identified as critical parameters in miniature lattice structures. Printed lattices that did not fully comply with FFF guidelines were capable of bearing compressive loads, even if surface quality and accuracy issues could not be fully resolved. Nevertheless, 3D printed FFF lattice structures could represent an improvement compared to other additive manufacturing processes, as they offer good control of cell geometry, and does not require additional post-processing.

Sign in / Sign up

Export Citation Format

Share Document