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.

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 Fiber Reinforced Composite Based Functionally Gradient Materials

1998 ◽  
Vol 7 (4) ◽  
pp. 096369359800700 ◽  
Author(s):  
VK Ganesh ◽  
S Ramakrishna ◽  
HJ Leck
Keyword(s):  
Mechanical Properties ◽  
Fiber Orientation ◽  
Orientation Angle ◽  
Gradient Material ◽  
Material System ◽  
Test Results ◽  
Fiber Reinforced ◽  
Fiber Reinforced Composite ◽  
Reinforced Composite ◽  
Functionally Gradient

A method of fabricating fiber-reinforced composite based functionally gradient material is described in this paper. The material has continuously varying mechanical properties along the length. The continuous variation of the mechanical properties is achieved by continuously varying the fiber orientation using the braiding process. The test results indicate an elastic modulus increase by about 42% from the largest braid angle to the smallest braid angle for the material system and the orientation angle considered in the present study.

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.

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.

Mechanical Properties of the Natural Heterogeneous Composites

2009 ◽  
Vol 628-629 ◽  
pp. 657-662 ◽  
Author(s):  
Ai Guang Lin ◽  
Xiao Fei Ding ◽  
Z.D. Xie ◽  
Bao Yuan Sun
Keyword(s):  
Mechanical Properties ◽  
Bending Strength ◽  
Gradient Material ◽  
Functional Requirements ◽  
Scallop Shell ◽  
Patinopecten Yessoensis ◽  
Three Point Bending ◽  
Functional Gradient Material ◽  
Scallop Shells ◽  
Parallel Case

According to the results of mechanical property tests, the mechanical properties of heterogeneous composite-Patinopecten yessoensis (scallop) shells are anisotropic and related closely to the microstructure. The results of compression and three-point bending tests indicated that the compressive strength which vertical load on the shell surface was approximately 3.8 times than the parallel case. The bending strength which applied to the external of the shell was about 2.2 times than it loaded from the inner surface. Patinopecten yessoensis (scallop) shell is organic-inorganic composite and has different microstructure in different location in according to its functional requirements. Patinopecten yessoensis (scallop) shell is typical bioactive functional gradient material, and its microstructure is worthy of heterogeneous composite material parts design.

Challenges in Designing and Manufacturing Fully Optimized Functional Gradient Material Objects

2014 ◽  
Author(s):  
Anthony Garland ◽  
Greg Mocko ◽  
Georges Fadel
Keyword(s):  
Manufacturing Process ◽  
Gradient Material ◽  
Promising Alternative ◽  
Object Properties ◽  
Functionally Gradient ◽  
Process Plans ◽  
Functional Gradient Material ◽  
Physical Response ◽  
Printing Processes ◽  
And Control

Functionally Gradient Materials (FGM) smoothly transition from one material to another within a single object, allowing engineers to customize the physical response of different regions of the object by modifying the material composition at each region. New FGM research makes design, manufacturing, and use of FGM objects a promising alternative to homogeneous objects or composites with one direction of gradation. Heterogeneous anisotropic artifacts can be manufactured with specific 3D printing processes and potentially bring significant increases in functionalities. However, many challenges exist while designing and manufacturing these objects. This paper explores these challenges and suggests needed research. In particular the ability to model FGM objects, setup and run optimization algorithms, create manufacturing process plans, and control the manufacturing process all need more research and better software tools. In addition, researchers must rigorously test optimally designed FGM objects in order to validate the FGM object properties and the FGM design process before adoption of FGM objects by industry is likely to occur.

An Efficient Design Optimization Method for Functional Gradient Material Objects Based on Finite Element Analysis

2015 ◽  
Author(s):  
Feng Zhang ◽  
Chi Zhou ◽  
Sonjoy Das
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Material Properties ◽  
Optimization Method ◽  
The Body ◽  
Gradient Material ◽  
Material Distribution ◽  
Element Analysis ◽  
Functional Gradient ◽  
Functional Gradient Material

Functional Gradient Material (FGM) is one of the most promising heterogeneous materials for its spatial continuity of material properties and functional flexibility. FGM is a well-studied research topic. In this paper, we utilize Finite Element Analysis (FEA) method to model objects with spatially varying material property. A two-stage optimization framework including Monte Carlo based global optimizer and gradient descent based local optimizer is proposed to achieve the optimal material composition in response to different user defined objectives. An error diffusion based halftoning technique is utilized to convert the continuous material distribution into discrete material distribution for viable manufacturing. The transition of the material properties are governed by predefined equations and only a few coefficients instead of large number of elements are to be optimized, therefore this optimization process is more computationally efficient than traditional techniques. Meanwhile it can automatically guarantee the smoothness of material transition along the body. Such design and optimization method has the potential to enable interactive multiple material modeling and simulation. Several experiments are carried out to demonstrate its efficiency and effectiveness.

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