Mechanical Behavior of 3D Printed Stochastic Lattice Structures

2016 ◽  
Vol 258 ◽  
pp. 225-228 ◽  
Author(s):  
Georgios Maliaris ◽  
Elias Sarafis
Keyword(s):  
Mechanical Behavior ◽  
Mechanical Response ◽  
Voronoi Tessellation ◽  
Element Model ◽  
Adjacent Cell ◽  
Lattice Structures ◽  
Voronoi Cells ◽  
Compressive Loads ◽  
3D Printed ◽  
Irregular Cell

Stochastic lattice structures are modeled using a generative algorithm. In particular, the voronoi tessellation technique is applied for modeling cellular solids with irregular cell geometry and variable strut sections. The ligaments are formed considering the volume and shape characteristics of the voronoi cells. This way, the strut cross section variability is linked to the adjacent cell topology. The developed geometry is used for 3D printing the structures through a high accuracy SLA 3D printer. The mechanical properties of the photosensitive resin were determined by conducting tension experiments on appropriate 3D printed specimens. The printed stochastic structures were subjected to compressive loads in order to investigate their mechanical response. A finite element model of the compressive tests using the generated geometry, is also developed. The calculated results provide a good correlation with the experimental ones and also provide precious insight for the characterization of the mechanical behavior of the tested structures.

A Proof of Concept Study of the Mechanical Behavior of Lattice Structures Used to Design a Shoulder Hemi-Prosthesis

2021 ◽  
Author(s):  
Marinela Peto ◽  
Oscar Aguilar-Rosas ◽  
Erick Erick Ramirez-Cedillo ◽  
Moises Jimenez ◽  
Adriana Hernandez ◽  
...  
Keyword(s):  
Mechanical Behavior ◽  
Mechanical Response ◽  
Mechanical Performance ◽  
Cell Attachment ◽  
Lattice Structure ◽  
Material Model ◽  
Patient Specific ◽  
Hexagonal Prism ◽  
Lattice Structures ◽  
Proof Of Concept

Abstract Lattice structures offer great benefits when employed in medical implants for cell attachment and growth (osseointegration), minimization of stress shielding phenomena, and weight reduction. This study is focused on a proof of concept for developing a generic shoulder hemi-prosthesis, from a patient-specific case of a 46 years old male with a tumor on the upper part of his humerus. A personalized biomodel was designed and a lattice structure was integrated in its middle portion, to lighten weight without affecting humerus’ mechanical response. To select the most appropriate lattice structure, three different configurations were initially tested: Tetrahedral Vertex Centroid (TVC), Hexagonal Prism Vertex Centroid (HPVC), and Cubic Diamond (CD). They were fabricated in resin by digital light processing and its mechanical behavior was studied via compression testing and finite element modeling (FEM). The selected structure according to the results was the HPVC, which was integrated in a digital twin of the biomodel to validate its mechanical performance through FEM but substituting the bone material model with a biocompatible titanium alloy (Ti6Al4V) suitable for prostheses fabrication. Results of the simulation showed acceptable levels of Von Mises stresses (325 MPa max.), below the elastic limit of the titanium alloys, and a better response (52 MPa max.) in a model with equivalent elastic properties, with stress performance in the same order of magnitude than the showed in bone’s material model.

scholarly journals Finite Element Simulation of the Thermo-mechanical Response of Graphene Reinforced Nanocomposites

2018 ◽  
Vol 188 ◽  
pp. 01016
Author(s):  
Androniki S. Tsiamaki ◽  
Nick K. Anifantis
Keyword(s):  
Finite Element ◽  
Mechanical Behavior ◽  
Mechanical Response ◽  
Volume Fraction ◽  
Matrix Material ◽  
Continuum Theory ◽  
Element Model ◽  
Multilayer Graphene ◽  
Temperature Changes ◽  
The Matrix

The research for new materials that can withstand extreme temperatures and present good mechanical behavior is of great importance. The interest is highly focused on the utilization of composites reinforced by nanomaterials. To cope with this goal the present work studies the mechanical response of graphene reinforced nanocomposite structures subjected to temperature changes. A computational finite element model has been developed that accounts for both the reinforcement and the matrix material phases. The model developed is based on both the continuum theory and the molecular mechanics theory, for the simulation of the three different material phases of the composite, respectively, i.e. the matrix, the intermediate transition phase and the reinforcement. Considering this model, the mechanical response of an appropriate representative volume element of the nanocomposite is simulated under various temperature changes. The study involves different types of reinforcement composed from either monolayer or multilayer graphene sheets. Apart from the investigation of the behavior of a nanocomposite with each particular type of the reinforcement, comparisons are also presented between them in order to reveal optimized material combinations. The principal parameters taken into consideration, which contribute also to the mechanical behavior of the nanocomposite, are its size, the sheet multiplicity as well as the volume fraction.

scholarly journals Influence of Crosslinking on the Mechanical Behavior of 3D Printed Alginate Scaffolds: Experimental and Numerical Approaches

2018 ◽  
Author(s):  
Saman Naghieh ◽  
Mohammad Reza Karamooz-Ravari ◽  
Md Sarker ◽  
Eva Karki ◽  
Xiongbiao Chen
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Mechanical Behavior ◽  
Three Dimensional ◽  
Decisive Role ◽  
Element Model ◽  
Tissue Scaffolds ◽  
3D Bioprinting ◽  
3D Printed ◽  
Numerical Approaches

Tissue scaffolds fabricated by three-dimensional (3D) bioprinting are attracting considerableattention for tissue engineering applications. Because the mechanical properties of hydrogelscaffolds should match the damaged tissue, changing various parameters during 3D bioprintinghas been studied to manipulate the mechanical behavior of the resulting scaffolds. Crosslinkingscaffolds using a cation solution (such as CaCl2) is also important for regulating the mechanicalproperties, but has not been well documented in the literature. Here, the effect of variedcrosslinking agent volume and crosslinking time on the mechanical behavior of 3D bioplottedalginate scaffolds was evaulated using both experimental and numerical methods. Compressiontests were used to measure the elastic modulus of each scaffold, then a finite element model wasdeveloped and a power model used to predict scaffold mechanical behavior. Results showed thatcrosslinking time and volume of crosslinker both play a decisive role in modulating the mechanicalproperties of 3D bioplotted scaffolds. Because mechanical properties of scaffolds can affect cellresponse, the findings of this study can be implemented to modulate the elastic modulus ofscaffolds according to the intended application.

Mechanical behavior of calcium sulfate scaffold prototypes built by solid free-form fabrication

2018 ◽  
Vol 24 (8) ◽  
pp. 1392-1400 ◽  
Author(s):  
Mitra Asadi-Eydivand ◽  
Mehran Solati-Hashjin ◽  
Noor Azuan Abu Osman
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Mechanical Behavior ◽  
Calcium Sulfate ◽  
Element Model ◽  
Porous Structures ◽  
Content Type ◽  
3D Printed ◽  
Printing Parameters ◽  
Binder Jetting

PurposeThis paper aims to investigate the mechanical behavior of three-dimensional (3D) calcium sulfate porous structures created by a powder-based 3D printer. The effects of the binder-jetting and powder-spreading orientations on the microstructure of the specimens are studied. A micromechanical finite element model is also examined to predict the properties of the porous structures under the load.Design/methodology/approachThe authors printed cylindrical porous and solid samples based on a predefined designed model to study the mechanical behavior of the prototypes. They investigated the effect of three main build bed orientations (x, y and z) on the mechanical behavior of solid and porous specimens fabricated in each direction then evaluated the micromechanical finite-element model for each direction. The strut fractures were analyzed by scanning electron microscopy, micro-computed tomography and the von Mises stress distribution.FindingsResults showed that the orientation of powder spreading and binder jetting substantially influenced the mechanical behavior of the 3D-printed prototypes. The samples that were fabricated parallel to the applied load had higher compressive strength compared with those printed perpendicular to the load. The results of the finite element analysis agreed with the results of the experimental mechanical testing.Research limitations/implicationsThe mechanical behavior was studied for the material and the 3D-printing machine used in this research. If one were to use another material formulation or machine, the printing parameters would have to be set accordingly.Practical implicationsThis work aimed to re-tune the control factors of an existing rapid prototyping process for the given machine. The authors achieved these goals without major changes in the already developed hardware and software architecture.Originality/valueThe results can be used as guidelines to set the printing parameters and a model to predict the mechanical properties of 3D-printed objects for the development of patient- and site-specific scaffolds.

Finite Element Simulation of the Hot Deformation Behavior of AA7075 Using a Coupled Thermo-Mechanical Crystal Plasticity Constitutive Model

2014 ◽  
Vol 553 ◽  
pp. 82-87 ◽  
Author(s):  
Lei Ting Li ◽  
Y.C. Lin ◽  
Ling Li ◽  
Lu Ming Shen
Keyword(s):  
Finite Element ◽  
Temperature Distribution ◽  
Grain Boundaries ◽  
Crystal Plasticity ◽  
Hot Deformation ◽  
Mechanical Response ◽  
Voronoi Tessellation ◽  
Element Model ◽  
Local Deformation ◽  
Electron Back Scatter Diffraction

Three-dimensional crystal plasticity finite element (CPFE) simulations are performed to study the coupled thermo-mechanical response of aluminium alloy 7075 under hot compression loadings. To improve the computational efficiency, a grain-scale representative volume element model with periodic boundary conditions is adopted to represent the macroscopic response. The initial grains are created using Voronoi tessellation method, and the grain orientations are obtained from the electron back-scatter diffraction test. The simulated results indicate that the effects of the grain properties on the local deformation and temperature distribution of the alloy are significant during the hot deformation. The temperature continuity can be found across some grain boundaries while there is a temperature gap at other grain boundaries. The proposed coupled thermo-mechanical CPFE model is able to provide detailed microstructure evolution and temperature distribution in the studied alloy during the hot deformation, which cannot be easily obtained by experiments.

scholarly journals Analysis of Influence and Formation for Uncoordinated Deformation in Tram Subgrade

2019 ◽  
Vol 136 ◽  
pp. 04037
Author(s):  
Yang Cai ◽  
Chongwei Huang ◽  
Xi Chen ◽  
Yu Sun ◽  
Dandan Guo
Keyword(s):  
Finite Element ◽  
Tensile Stress ◽  
Finite Element Model ◽  
Mechanical Behavior ◽  
Compressive Stress ◽  
Mechanical Response ◽  
Element Model ◽  
The Other ◽  
3D Finite Element ◽  
Remarkable Effect

Aiming at horizontal and vertical uncoordinated deformation formation in Tram Subgrade, a 3D finite element model was established, which was used to analyse the mechanical response of tram monolithic roadbed on multiple depth and width of uncoordinated deformation. The results show that the uncoordinated deformation’s depth has little influence on the mechanical behavior of roadbed, and it indicates that there was remainder disengaging under the monolithic roadbed by the load of tram. On the other side, the width of uncoordinated deformation has a remarkable effect on outstanding to the horizontal tensile stress (σdy) in the slab bottom, deflection (Dd) on the top of slab, compressive stress (σsz) on the top of soil, and deflection (Dss) on the top of soil. The deflection on the top of subgrade surface is about 1.61mm. Therefore, the designer’s attention should be paid to avoid uncoordinated deformation width in the project, and avoid destroy of monolithic slab.

scholarly journals Study of the Mechanical Behavior of Subcellular Organelles Using a 3D Finite Element Model of the Tensegrity Structure

2020 ◽  
Vol 11 (1) ◽  
pp. 249
Author(s):  
Gholamreza Mohammadi Khunsaraki ◽  
Hanieh Niroomand Oscuii ◽  
Arkady Voloshin
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Mechanical Behavior ◽  
Mechanical Response ◽  
Reaction Force ◽  
Element Model ◽  
Subcellular Organelles ◽  
Atomic Force ◽  
Cell Components ◽  
Tensegrity Model

A tensegrity model can be used to describe the mechanical behavior of living cells. A finite element model (FEM) was used to assess the mechanical contribution of subcellular organelles. Continuum parts like the cytoplasm and membrane were modeled as continuous elements, while the tensegrity was chosen to model the cytoskeleton and nucleoskeleton. An atomic force microscope load was implemented to simulate the external load. The cell components were loaded separately to evaluate their mechanical contributions. The analysis started with a single cytoplasm and each of the cell components was added in consecutive steps. The results showed that the cytoskeleton carried the largest part of the reaction force. The cytoplasm was the second important component of the cell’s mechanical response. It was shown that the nucleoskeleton has a stiffer structure than the membrane and cytoplasm. The cytoskeleton supported approximately 90% of the reaction force, while the cytoplasm carried 9% and the shell parts and nucleoskeleton were responsible for about 1%.

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.

scholarly journals Tuning of Static and Dynamic Mechanical Response of LPBFed AlSi10Mg Lattice Structures through heat Treatments

2021 ◽  
Author(s):  
Jacopo Fiocchi ◽  
Chiara Bregoli ◽  
Giulio Gerosa ◽  
Ausonio Tuissi ◽  
Carlo Alberto Biffi
Keyword(s):  
Mechanical Response ◽  
Heat Treatments ◽  
Lattice Structures ◽  
Dynamic Mechanical

scholarly journals Experimental and Numerical Evaluation of Mechanical Properties of 3D-Printed Stainless Steel 316L Lattice Structures

2021 ◽  
Author(s):  
M. Carraturo ◽  
G. Alaimo ◽  
S. Marconi ◽  
E. Negrello ◽  
E. Sgambitterra ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Mechanical Behavior ◽  
Numerical Simulations ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Lattice Structures ◽  
Stainless Steel 316L ◽  
Research Attention ◽  
Octet Truss

AbstractAdditive manufacturing (AM), and in particular selective laser melting (SLM) technology, allows to produce structural components made of lattice structures. These kinds of structures have received a lot of research attention over recent years due to their capacity to generate easy-to-manufacture and lightweight components with enhanced mechanical properties. Despite a large amount of work available in the literature, the prediction of the mechanical behavior of lattice structures is still an open issue for researchers. Numerical simulations can help to better understand the mechanical behavior of such a kind of structure without undergoing long and expensive experimental campaigns. In this work, we compare numerical and experimental results of a uniaxial tensile test for stainless steel 316L octet-truss lattice specimen. Numerical simulations are based on both the nominal as-designed geometry and the as-build geometry obtained through the analysis of µ-CT images. We find that the use of the as-build geometry is fundamental for an accurate prediction of the mechanical behavior of lattice structures.

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