scholarly journals Mechanical Properties and Energy Absorption Characteristics of Additively Manufactured Lightweight Novel Re-Entrant Plate-Based Lattice Structures

Polymers ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3882
Author(s):  
Sultan Al Hassanieh ◽  
Ahmed Alhantoobi ◽  
Kamran A. Khan ◽  
Muhammad A. Khan
Keyword(s):  
Mechanical Properties ◽  
Energy Absorption ◽  
Power Law ◽  
Elastic Anisotropy ◽  
Lattice Structures ◽  
Numerical Homogenization ◽  
Anisotropic Behavior ◽  
Cubic Symmetry ◽  
Compressive Response ◽  
Hybrid Plate

In this work, three novel re-entrant plate lattice structures (LSs) have been designed by transforming conventional truss-based lattices into hybrid-plate based lattices, namely, flat-plate modified auxetic (FPMA), vintile (FPV), and tesseract (FPT). Additive manufacturing based on stereolithography (SLA) technology was utilized to fabricate the tensile, compressive, and LS specimens with different relative densities (ρ). The base material’s mechanical properties obtained through mechanical testing were used in a finite element-based numerical homogenization analysis to study the elastic anisotropy of the LSs. Both the FPV and FPMA showed anisotropic behavior; however, the FPT showed cubic symmetry. The universal anisotropic index was found highest for FPV and lowest for FPMA, and it followed the power-law dependence of ρ. The quasi-static compressive response of the LSs was investigated. The Gibson–Ashby power law (≈ρn) analysis revealed that the FPMA’s Young’s modulus was the highest with a mixed bending–stretching behavior (≈ρ1.30), the FPV showed a bending-dominated behavior (≈ρ3.59), and the FPT showed a stretching-dominated behavior (≈ρ1.15). Excellent mechanical properties along with superior energy absorption capabilities were observed, with the FPT showing a specific energy absorption of 4.5 J/g, surpassing most reported lattices while having a far lower density.

Architected functionally graded porous lattice structures for optimized elastic-plastic behavior

2020 ◽  
Vol 234 (8) ◽  
pp. 1099-1116 ◽  
Author(s):  
Mahshid Mahbod ◽  
Masoud Asgari ◽  
Christian Mittelstedt
Keyword(s):  
Mechanical Properties ◽  
Energy Absorption ◽  
Specific Energy ◽  
Elastic Moduli ◽  
Maximum Stress ◽  
Functionally Graded ◽  
Plastic Behavior ◽  
Lattice Structures ◽  
Porous Structures ◽  
Specific Energy Absorption

In this paper, the elastic–plastic mechanical properties of regular and functionally graded additively manufactured porous structures made by a double pyramid dodecahedron unit cell are investigated. The elastic moduli and also energy absorption are evaluated via finite element analysis. Experimental compression tests are performed which demonstrated the accuracy of numerical simulations. Next, single and multi-objective optimizations are performed in order to propose optimized structural designs. Surrogated models are developed for both elastic and plastic mechanical properties. The results show that elastic moduli and the plastic behavior of the lattice structures are considerably affected by the cell geometry and relative density of layers. Consequently, the optimization leads to a significantly better performance of both regular and functionally graded porous structures. The optimization of regular lattice structures leads to great improvement in both elastic and plastic properties. Specific energy absorption, maximum stress, and the elastic moduli in x- and y-directions are improved by 24%, 79%, 56%, and 9%, respectively, compared to the base model. In addition, in the functionally graded optimized models, specific energy absorption and normalized maximum stress are improved by 64% and 56%, respectively, in comparison with the base models.

scholarly journals Mechanical properties of snow using indentation tests: size effects

2013 ◽  
Vol 59 (213) ◽  
pp. 35-46 ◽  
Author(s):  
Daisy Huang ◽  
Jonah H. Lee
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Energy Absorption ◽  
Power Law ◽  
Size Effects ◽  
Peak Strength ◽  
Seasonal Snow ◽  
Average Grain Size ◽  
Indentation Tests ◽  
Natural Snow

AbstractAn attempt is made to obtain and quantify the mechanical properties of two common types of seasonal snow on the ground. Different samples of natural snow whose metamorphism had stabilized (such as would remain on a road throughout winter in a cold, snowy area) were gathered and tested using mesoscale indentation tests (metrics on the order of mm to cm). Results from the stress vs displacement curves from indentation indicated that (1) first peak strength decreased, according to a power law, with increasing indenter size and was not affected by snow average grain size, (2) plateau strength decreased with increasing indenter size, and snow compaction strength might be calculated from these data, and (3) mean energy absorption density during indentation was independent of indenter size in some size ranges, and decreased with increasing indenter size in other size ranges.

Mechanical performance of additively manufactured uniform and graded porous structures based on topology-optimized unit cells

2020 ◽  
pp. 095440622094711
Author(s):  
Mohsen Teimouri ◽  
Masoud Asgari
Keyword(s):  
Mechanical Properties ◽  
Energy Absorption ◽  
Mechanical Performance ◽  
Functionally Graded ◽  
Geometrical Parameters ◽  
Lattice Structures ◽  
Shell Type ◽  
Two Samples ◽  
Unit Cells ◽  
Thin Walled

A topology optimization (TO) method is used to develop new and efficient unit cells to be used in additively manufactured porous lattice structures. Two types of unit cells including solid and thin-walled shell-type ones are introduced for generating the desired regular and functionally graded (FG) lattice structures. To evaluate structural stiffness and crushing behavior of the proposed lattice structures, their mechanical properties, and energy absorption parameters have been calculated through implementing finite element (FE) simulations on them. To validate the simulations, two samples were fabricated by a stereolithography (SLA) machine. Besides, the effects of geometrical parameters and optimizing scheme of the unit cells on the mechanical properties of the proposed structures are studied. Consequently, energy absorption parameters have been calculated and compared for both the solid and thin-walled lattice structures to evaluate their ability in energy absorption. It was found in general that for the solid lattice structures, the mechanical properties, and the crushing parameters are directly affected by porosity though in shell-type ones superior mechanical properties could be achieved even for a smaller proportion of material usage.

scholarly journals The Mechanical Properties and Elastic Anisotropy of η’-Cu6Sn5 and Cu3Sn Intermetallic Compounds

Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1562
Author(s):  
Chao Ding ◽  
Jian Wang ◽  
Tianhan Liu ◽  
Hongbo Qin ◽  
Daoguo Yang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Intermetallic Compound ◽  
Intermetallic Compounds ◽  
First Principles ◽  
Elastic Anisotropy ◽  
First Principles Calculations ◽  
Anisotropic Behavior ◽  
Ductile Materials ◽  
The Relationship

Full intermetallic compound (IMC) solder joints present fascinating advantages in high-temperature applications. In this study, the mechanical properties and elastic anisotropy of η’-Cu6Sn5 and Cu3Sn intermetallic compounds were investigated using first-principles calculations. The values of single-crystal elastic constants, the elastic (E), shear (G), and bulk (B) moduli, and Poisson’s ratio (ν) were identified. In addition, the two values of G/B and ν indicated that the two IMCs were ductile materials. The elastic anisotropy of η’-Cu6Sn5 was found to be higher than Cu3Sn by calculating the universal anisotropic index. Furthermore, an interesting discovery was that the above two types of monocrystalline IMC exhibited mechanical anisotropic behavior. Specifically, the anisotropic degree of E and B complied with the following relationship: η’-Cu6Sn5 > Cu3Sn; however, the relationship was Cu3Sn > η’-Cu6Sn5 for the G. It is noted that the anisotropic degree of E and G was similar for the two IMCs. In addition, the anisotropy of the B was higher than the G and E, respectively, for η’-Cu6Sn5; however, in the case of Cu3Sn, the anisotropic degree of B, G, and E was similar.

scholarly journals Compressive Properties of Functionally Graded Bionic Bamboo Lattice Structures Fabricated by FDM

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4410
Author(s):  
Zhou Wen ◽  
Ming Li
Keyword(s):  
Mechanical Properties ◽  
Energy Absorption ◽  
Honeycomb Structure ◽  
Absorption Capacity ◽  
Functionally Graded ◽  
Honeycomb Lattice ◽  
Lattice Structures ◽  
Compression Tests ◽  
Uniform Lattice ◽  
Static Compression

Bionic design is considered a promising approach to improve the performance of lattice structures. In this work, bamboo-inspired cubic and honeycomb lattice structures with graded strut diameters were designed and manufactured by 3D printing. Uniform lattice structures were also designed and fabricated for comparison. Quasi-static compression tests were conducted on lattice structures, and the effects of the unit cell and structure on the mechanical properties, energy absorption and deformation mode were investigated. Results indicated that the new bionic bamboo structure showed similar mechanical properties and energy absorption capacity to the honeycomb structure but performed better than the cubic structure. Compared with the uniform lattice structures, the functionally graded lattice structures showed better performance in terms of initial peak strength, compressive modulus and energy absorption.

scholarly journals The Effect of Functional Gradient Material Distribution and Patterning on Torsional Properties of Lattice Structures Manufactured Using MultiJet Fusion Technology

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6521
Author(s):  
Yeabsra Mekdim Hailu ◽  
Aamer Nazir ◽  
Shang-Chih Lin ◽  
Jeng-Ywan Jeng
Keyword(s):  
Mechanical Properties ◽  
Energy Absorption ◽  
Torsional Stiffness ◽  
Gradient Material ◽  
Uniform Density ◽  
Lattice Structures ◽  
Material Distribution ◽  
Functionally Gradient ◽  
Functional Gradient Material ◽  
Torsional Properties

Functionally graded lattice structures have attracted much attention in engineering due to their excellent mechanical performance resulting from their optimized and application-specific properties. These structures are inspired by nature and are important for a lightweight yet efficient and optimal functionality. They have enhanced mechanical properties over the uniform density counterparts because of their graded design, making them preferable for many applications. Several studies were carried out to investigate the mechanical properties of graded density lattice structures subjected to different types of loadings mainly related to tensile, compression, and fatigue responses. In applications related to biomedical, automotive, and aerospace sectors, dynamic bending and rotational stresses are critical load components. Therefore, the study of torsional properties of functionally gradient lattice structures will contribute to a better implementation of lattice structures in several sectors. In this study, several functionally gradient triply periodic minimal surfaces structures and strut-based lattice structures were designed in cylindrical shapes having 40% relative density. The HP Multi Jet Fusion 4200 3D printer was used to fabricate all specimens for the experimental study. A torsional experiment until the failure of each structure was conducted to investigate properties of the lattice structures such as torsional stiffness, energy absorption, and failure characteristics. The results showed that the stiffness and energy absorption of structures can be improved by an effective material distribution that corresponds to the stress concentration due to torsional load. The TPMS based functionally gradient design showed a 35% increase in torsional stiffness and 15% increase in the ultimate shear strength compared to their uniform counterparts. In addition, results also revealed that an effective material distribution affects the failure mechanism of the lattice structures and delays the plastic deformation, increasing their resistance to torsional loads.

Mechanical properties and energy absorption of FCC lattice structures with different orientation angles

2020 ◽  
Vol 231 (8) ◽  
pp. 3129-3144 ◽  
Author(s):  
Peng Wang ◽  
Yijie Bian ◽  
Fan Yang ◽  
Hualin Fan ◽  
Bailin Zheng
Keyword(s):  
Mechanical Properties ◽  
Energy Absorption ◽  
Lattice Structures ◽  
Fcc Lattice
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