Analytical Solution and Experimental Study of Effective Young's Modulus of Selective Laser Melting-Fabricated Lattice Structure With Triangular Unit Cells

2018 ◽  
Vol 140 (9) ◽  
Author(s):  
Jie Niu ◽  
Hui Leng Choo ◽  
Wei Sun ◽  
Sui Him Mok
Keyword(s):  
Analytical Solution ◽  
Young’S Modulus ◽  
Selective Laser Melting ◽  
Triangular Lattice ◽  
Young's Modulus ◽  
Numerical Results ◽  
Lattice Structures ◽  
Shape Parameters ◽  
Laser Melting ◽  
Unit Cells

Research on materials, design, processing, and manufacturability of parts produced by additive manufacturing (AM) has been investigated significantly in the past. However, limited research on tensile behavior of cellular lattice structures by AM was carried out. In this paper, effective tensile Young's modulus, E*, of triangular lattice structures was determined. Firstly, analytical solution was derived based on Euler–Bernoulli beam theory. Then, numerical results of E* were obtained by finite element analysis (FEA) for triangular lattice structures classified by three shape parameters. The effects of side length, L, beam thickness, t, and height, h, on E* were investigated individually. FEA results revealed that there is a relationship between E* and the relative density and shape parameters. Among them, t has the most significant effect on E*. Numerical results were also compared with the results from modified general function for cellular structures and modified formula for triangular honeycomb. The E* predicted by the proposed analytical solution shows the best agreement with the numerical results. Finally, tensile tests were carried out using AlSi10 Mg triangular lattice structures manufactured by selective laser melting (SLM) process. The experimental results show that both analytical and numerical solutions are able to predict E* with good accuracy. In the future, the proposed solution can be used to design lightweight structures with triangular unit cells.

Evaluation of Physicomechanical Properties of Ti-45Nb Specimens Obtained by Selective Laser Melting

2017 ◽  
Vol 743 ◽  
pp. 9-12
Author(s):  
Zhanna G. Kovalevskaya ◽  
Margarita A. Khimich ◽  
Andrey V. Belyakov
Keyword(s):  
Young’S Modulus ◽  
Selective Laser Melting ◽  
Laser Power ◽  
Young's Modulus ◽  
Scanning Speed ◽  
Physicomechanical Properties ◽  
Optical Methods ◽  
Laser Melting ◽  
Average Value ◽  
Hardness Tester

Porosity, values of nanohardness and Young’s modulus of the specimens obtained with the method of selective laser melting were measured with optical methods, scanning electron microscopy and Nano Hardness Tester NHT-S-AX-000X device for measuring physicomechanical properties. Ti-45wt%Nb powder obtained with mechanical alloying was used for selective laser melting. The results have shown that increased heat input due to the laser power growth up to 80 W and scanning speed decrease down to 40 mm/s decreases the porosity of the specimen. The nanohardness average value is not sensitive to the changes of scanning modes in the investigated range. The Young’s modulus decreases with energy input increase.

Manufacturing of Porous Biomaterials for Dental Implant Applications through Selective Laser Melting

2012 ◽  
Vol 535-537 ◽  
pp. 1222-1229 ◽  
Author(s):  
Francesco Cardaropoli ◽  
Vittorio Alfieri ◽  
Fabrizia Caiazzo ◽  
Vincenzo Sergi
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Dental Implants ◽  
Selective Laser Melting ◽  
Young's Modulus ◽  
Bulk Material ◽  
Total Porosity ◽  
Porous Metals ◽  
Efficient Technology ◽  
Laser Melting

The paper discusses the possibility of manufacturing dental implants through Selective Laser Melting (SLM) of a Ti-6Al-4V alloy powder. Among all possible biomaterials, this alloy is widely used in biomedical applications due to high biocompatibility. Selective Laser Melting allows to obtain biomaterials with peculiar characteristics in terms of porosity gradient, roughness, customized geometry, and mechanical properties. Influence of input process parameters on porosity and analysis of Selective Laser Melting capabilities in implant dentistry have been focused. Porosity is a key parameter in dental implants as it affects stiffness, which is related to Young’s modulus. Ti-6Al-4V bulk material presents a Young’s modulus of 110 GPa, whereas the bone one ranges from 10 to 26 GPa. The relative difference of mechanical properties causes the phenomenon of stress shielding, which has a detrimental effect on the longevity of dental implants. Total porosity is important in reducing the effective modulus of porous metals. Biomaterials specimens obtained during experimental phase have been examined in terms of porosity (in inverse ratio to relative density), microstructure, microhardness and roughness. According to test results discussed in this paper, Selective Laser Melting is proved to be an efficient technology for the construction of Ti-6Al-4V dental implants, because biomaterials with adequate properties can be obtained changing processing parameters. Other fabrication techniques fail to produce biomaterials for dental implants with the desired features.

scholarly journals A parametric prediction of the Young’s modulus of polymers enhanced with ΜWCNTs

2018 ◽  
Vol 233 ◽  
pp. 00025
Author(s):  
P.V. Polydoropoulou ◽  
K.I. Tserpes ◽  
Sp.G. Pantelakis ◽  
Ch.V. Katsiropoulos
Keyword(s):  
Young’S Modulus ◽  
Elastic Properties ◽  
Young's Modulus ◽  
Experimental Results ◽  
Scale Model ◽  
Fe Model ◽  
Multi Scale ◽  
Unit Cells ◽  
Random Dispersion

In this work a multi-scale model simulating the effect of the dispersion, the waviness as well as the agglomerations of MWCNTs on the Young’s modulus of a polymer enhanced with 0.4% MWCNTs (v/v) has been developed. Representative Unit Cells (RUCs) have been employed for the determination of the homogenized elastic properties of the MWCNT/polymer. The elastic properties computed by the RUCs were assigned to the Finite Element (FE) model of a tension specimen which was used to predict the Young’s modulus of the enhanced material. Furthermore, a comparison with experimental results obtained by tensile testing according to ASTM 638 has been made. The results show a remarkable decrease of the Young’s modulus for the polymer enhanced with aligned MWCNTs due to the increase of the CNT agglomerations. On the other hand, slight differences on the Young’s modulus have been observed for the material enhanced with randomly-oriented MWCNTs by the increase of the MWCNTs agglomerations, which might be attributed to the low concentration of the MWCNTs into the polymer. Moreover, the increase of the MWCNTs waviness led to a significant decrease of the Young’s modulus of the polymer enhanced with aligned MWCNTs. The experimental results in terms of the Young’s modulus are predicted well by assuming a random dispersion of MWCNTs into the polymer.

scholarly journals Organizing Cells Within Non-Periodic Microarchitectured Materials That Achieve Graded Thermal Expansions

2015 ◽  
Author(s):  
Jonathan B. Hopkins ◽  
Lucas A. Shaw ◽  
Todd H. Weisgraber ◽  
George R. Farquar ◽  
Christopher D. Harvey ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Thermal Expansion ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Element Analysis ◽  
Thermal Expansion Coefficients ◽  
Large Lattice ◽  
Unit Cells ◽  
Expansion Coefficients ◽  
Bulk Behavior

The aim of this paper is to introduce an approach for optimally organizing a variety of different unit cell designs within a large lattice such that the bulk behavior of the lattice exhibits a desired Young’s modulus with a graded change in thermal expansion over its geometry. This lattice, called a graded microarchitectured material, can be sandwiched between two other materials with different thermal expansion coefficients to accommodate their different expansions or contractions caused by changing temperature while achieving a desired uniform stiffness. First, this paper provides the theory necessary to calculate the thermal expansion and Young’s modulus of large multi-material lattices that consist of periodic (i.e., repeating) unit cells of the same design. Then it introduces the theory for calculating the graded thermal expansions of a large multimaterial lattice that consists of non-periodic unit cells of different designs. An approach is then provided for optimally designing and organizing different unit cells within a lattice such that both of its ends achieve the same thermal expansion as the two materials between which the lattice is sandwiched. A MATLAB tool is used to generate images of the undeformed and deformed lattices to verify their behavior and various examples are provided as case studies. The theory provided is also verified and validated using finite element analysis and experimentation.

scholarly journals Damping behavior of 316L lattice structures produced by Selective Laser Melting

2018 ◽  
Vol 160 ◽  
pp. 1010-1018 ◽  
Author(s):  
Francesco Rosa ◽  
Stefano Manzoni ◽  
Riccardo Casati
Keyword(s):  
Selective Laser Melting ◽  
Lattice Structures ◽  
Laser Melting ◽  
Damping Behavior
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