The Mechanical Properties of Hierarchical Truss-Walled Lattice Materials

To construct a hierarchical lattice structure (HLS), truss wall is introduced into ordinary lattice structure (OLS). Young’s modulus, yield strength and buckling stress of HLSs were evaluated theoretically. Failure maps of different HLSs were plotted and compared based on the theoretical analyses. It is indicated that mechanical behaviors of hexagonal HLSs made of triangular lattice walls can be greatly enhanced by the hierarchical wall structure, while properties of triangular HLSs are weakened, except the anti-buckling resistance. When HLSs are made of bending-dominated honeycomb walls, their properties will be reduced, indicating that hierarchical structure should be appropriately designed to make ultra-light structures benefit from this construction. This viewpoint is strengthened by the discussions on the performances of high order lattice structures, where only bending-dominated HLSs with stretching-dominated lattice wall benefit from the hierarchy.

Download Full-text

Dynamic Loading of Lattice Structure Made by Selective Laser Melting-Numerical Model with Substitution of Geometrical Imperfections

Materials ◽

10.3390/ma11112129 ◽

2018 ◽

Vol 11 (11) ◽

pp. 2129 ◽

Cited By ~ 7

Author(s):

Radek Vrána ◽

Ondřej Červinek ◽

Pavel Maňas ◽

Daniel Koutný ◽

David Paloušek

Keyword(s):

Mechanical Properties ◽

Numerical Model ◽

Cross Section ◽

Lattice Structure ◽

Low Velocity Impact ◽

Lattice Structures ◽

Laser Melting ◽

Low Velocity ◽

Velocity Impact ◽

Geometrical Imperfections

Selective laser melting (SLM) is an additive technology that allows for the production of precisely designed complex structures for energy absorbing applications from a wide range of metallic materials. Geometrical imperfections of the SLM fabricated lattice structures, which form one of the many thin struts, can lead to a great difference in prediction of their behavior. This article deals with the prediction of lattice structure mechanical properties under dynamic loading using finite element method (FEA) with inclusion of geometrical imperfections of the SLM process. Such properties are necessary to know especially for the application of SLM fabricated lattice structures in automotive or aerospace industries. Four types of specimens from AlSi10Mg alloy powder material were manufactured using SLM for quasi-static mechanical testing and determination of lattice structure mechanical properties for the FEA material model, for optical measurement of geometrical accuracy, and for low-velocity impact testing using the impact tester with a flat indenter. Geometries of struts with elliptical and circular cross-sections were identified and tested using FEA. The results showed that, in the case of elliptical cross-section, a significantly better match was found (2% error in the Fmax) with the low-velocity impact experiments during the whole deformation process compared to the circular cross-section. The FEA numerical model will be used for future testing of geometry changes and its effect on mechanical properties.

Download Full-text

Compressive Behavior and Deformation Characteristic of Al-Based Auxetic Lattice Structure Filled with Silicate Rubber

Materials Science Forum ◽

10.4028/www.scientific.net/msf.933.240 ◽

2018 ◽

Vol 933 ◽

pp. 240-245

Author(s):

Ying Ying Xue ◽

Xing Fu Wang ◽

Xin Fu Wang ◽

Fu Sheng Han

Keyword(s):

Mechanical Properties ◽

Relative Density ◽

Composite Structures ◽

Lattice Structure ◽

Deformation Characteristic ◽

Damage Mechanism ◽

Lattice Structures ◽

Compressive Behavior ◽

Plateau Region ◽

Pressure Infiltration

The composites composed of Al-based auxetic lattice structures and silicate rubbers were fabricated by pressure infiltration technology. The compressive behavior and deformation characteristic of the composites were investigated related with the relative densities of the auxetic lattice structures. We found that the composites exhibit a longer plateau region than the non-filled Al-based auxetic lattice structures, and the relative density of the auxetic lattice structures play an important role in the compressive mechanical properties, the higher the relative density, the higher flow stress. It is also noticing that, the composite structures show different deformation and damage mechanism due to the filled incompressible silicate rubber. It is expected that the study may provide useful information for the applications of composite structure.

Download Full-text

Dual Graded Lattice Structures: Generation Framework and Mechanical Properties Characterization

Polymers ◽

10.3390/polym13091528 ◽

2021 ◽

Vol 13 (9) ◽

pp. 1528

Author(s):

Khaled G. Mostafa ◽

Guilherme A. Momesso ◽

Xiuhui Li ◽

David S. Nobes ◽

Ahmed J. Qureshi

Keyword(s):

Mechanical Properties ◽

Relative Density ◽

Lattice Structure ◽

Cell Types ◽

Functionally Graded ◽

Unit Cell ◽

Lattice Structures ◽

Unit Cells ◽

Mechanical Properties Characterization ◽

Graded Lattice

Additive manufacturing (AM) enables the production of complex structured parts with tailored properties. Instead of manufacturing parts as fully solid, they can be infilled with lattice structures to optimize mechanical, thermal, and other functional properties. A lattice structure is formed by the repetition of a particular unit cell based on a defined pattern. The unit cell’s geometry, relative density, and size dictate the lattice structure’s properties. Where certain domains of the part require denser infill compared to other domains, the functionally graded lattice structure allows for further part optimization. This manuscript consists of two main sections. In the first section, we discussed the dual graded lattice structure (DGLS) generation framework. This framework can grade both the size and the relative density or porosity of standard and custom unit cells simultaneously as a function of the structure spatial coordinates. Popular benchmark parts from different fields were used to test the framework’s efficiency against different unit cell types and grading equations. In the second part, we investigated the effect of lattice structure dual grading on mechanical properties. It was found that combining both relative density and size grading fine-tunes the compressive strength, modulus of elasticity, absorbed energy, and fracture behavior of the lattice structure.

Download Full-text

Design Optimization of Lattice Structures under Compression: Study of Unit Cell Types and Cell Arrangements

Materials ◽

10.3390/ma15010097 ◽

2021 ◽

Vol 15 (1) ◽

pp. 97

Author(s):

Kwang-Min Park ◽

Kyung-Sung Min ◽

Young-Sook Roh

Keyword(s):

Mechanical Properties ◽

Compressive Strength ◽

Relative Density ◽

Lattice Structure ◽

Density Ratio ◽

Cell Types ◽

Unit Cell ◽

Structure Characterization ◽

Optimized Design ◽

Lattice Structures

Additive manufacturing enables innovative structural design for industrial applications, which allows the fabrication of lattice structures with enhanced mechanical properties, including a high strength-to-relative-density ratio. However, to commercialize lattice structures, it is necessary to define the designability of lattice geometries and characterize the associated mechanical responses, including the compressive strength. The objective of this study was to provide an optimized design process for lattice structures and develop a lattice structure characterization database that can be used to differentiate unit cell topologies and guide the unit cell selection for compression-dominated structures. Linear static finite element analysis (FEA), nonlinear FEA, and experimental tests were performed on 11 types of unit cell-based lattice structures with dimensions of 20 mm × 20 mm × 20 mm. Consequently, under the same relative density conditions, simple cubic, octahedron, truncated cube, and truncated octahedron-based lattice structures with a 3 × 3 × 3 array pattern showed the best axial compressive strength properties. Correlations among the unit cell types, lattice structure topologies, relative densities, unit cell array patterns, and mechanical properties were identified, indicating their influence in describing and predicting the behaviors of lattice structures.

Download Full-text

How to Surpass the Deep-Sea Glass Sponges Mechanically

10.20944/preprints202112.0042.v1 ◽

2021 ◽

Author(s):

Quan-Wei Li ◽

Bohua Sun

Keyword(s):

Mechanical Properties ◽

Deep Sea ◽

Lattice Structure ◽

Structural Complexity ◽

Theory Of Elasticity ◽

Square Lattice ◽

Engineering Structures ◽

Biomimetic Design ◽

Lattice Materials ◽

Bionic Structure

The biomimetic design of engineering structures is based on biological structures with excellent mechanical properties, which are the result of billions of years of evolution. However, current biomimetic structures, such as ordered lattice materials, are still inferior to many biological materials in terms of structural complexity and mechanical properties. For example, the structure of \textit{Euplectella aspergillum}, a type of deep-sea glass sponge, is an eye-catching source of inspiration for biomimetic design; however, guided by scientific theory, how to engineer structures surpassing the mechanical properties of \textit{E. aspergillum} remains an unsolved problem. The lattice structure of the skeleton of \textit{E. aspergillum} consists of vertically, horizontally, and diagonally oriented struts, which provide superior strength and flexural resistance compared with the conventional square lattice structure. Herein, the structure of \textit{E. aspergillum} was investigated in detail, and by using the theory of elasticity, a lattice structure inspired by the bionic structure was proposed. The mechanical properties of the sponge-inspired lattice structure surpassed the sponge structure under a variety of loading conditions, and the excellent performance of this configuration was verified experimentally. The proposed lattice structure can greatly improve the mechanical properties of engineering structures, and it improves strength without much redundancy of material. This study achieved the first surpassing of the mechanical properties of an existing sponge-mimicking design. This design can be applied to lattice structures, truss systems, and metamaterial cells.

Download Full-text

Mechanical Properties of Flexible TPU-Based 3D Printed Lattice Structures: Role of Lattice Cut Direction and Architecture

Polymers ◽

10.3390/polym13172986 ◽

2021 ◽

Vol 13 (17) ◽

pp. 2986

Author(s):

Victor Beloshenko ◽

Yan Beygelzimer ◽

Vyacheslav Chishko ◽

Bogdan Savchenko ◽

Nadiya Sova ◽

...

Keyword(s):

Mechanical Properties ◽

Lattice Structure ◽

Pore Space ◽

Thermoplastic Polyurethane ◽

Bending Tests ◽

Three Point Bending ◽

Lattice Materials ◽

3D Printed ◽

Anisotropy Of Mechanical Properties

This study addresses the mechanical behavior of lattice materials based on flexible thermoplastic polyurethane (TPU) with honeycomb and gyroid architecture fabricated by 3D printing. Tensile, compression, and three-point bending tests were chosen as mechanical testing methods. The honeycomb architecture was found to provide higher values of rigidity (by 30%), strength (by 25%), plasticity (by 18%), and energy absorption (by 42%) of the flexible TPU lattice compared to the gyroid architecture. The strain recovery is better in the case of gyroid architecture (residual strain of 46% vs. 31%). TPUs with honeycomb architecture are characterized by anisotropy of mechanical properties in tensile and three-point bending tests. The obtained results are explained by the peculiarities of the lattice structure at meso- and macroscopic level and by the role of the pore space.

Download Full-text

FEM analysis of 3D lattice structures of ABS material

Turkish Journal of Computer and Mathematics Education (TURCOMAT) ◽

10.17762/turcomat.v12i6.2060 ◽

2021 ◽

Vol 12 (6) ◽

pp. 648-652

Author(s):

Seong-Gyu Cho Et.al

Keyword(s):

Mechanical Properties ◽

Stress Concentration ◽

Lattice Structure ◽

Three Dimensional ◽

Parametric Modeling ◽

Lattice Structures ◽

Filling Rate ◽

Dimensional Lattice ◽

Stress And Deformation ◽

Fcc Structure

FDM is a typical additive manufacturing method. Since FDM is a method of stacking layers one by one, it generally has a flat lattice structure. In this study, by checking the distribution of stress and deformation for several lattice structures made of ABS material, it is intended to find a structure with better mechanical properties with less material. Several three-dimensional lattice structures are modeled using parametric modeling. Subsequently, a constant pressure is applied to the same area to check the stress and strain distribution. A structure with a low maximum stress value in the stress concentration region and a small amount of deformation will have the best mechanical properties. To do this, parametric modeling is performed using Inventor to model four three-dimensional lattice structures. Afterwards, use Ansys Workbench to check the stress and deformation distribution. Looking at the stress distribution, stress concentration occurred in the truss supporting the upper surface of the SC structure. In the BCC and PTC structures, stress concentration occurred at the point where the upper surface and the truss met. In the FCC structure, it can be seen that the load is distributed throughout the truss structure. Looking at the deformation distribution, both the SC and BCC structures show similar amounts of deformation. It was confirmed that the FCC structure had less maximum deformation than the PTC structure with the thickest truss. Unlike previous studies, it was confirmed that the higher the internal filling rate, the better the mechanical properties may not come out. The FDM method can obtain different mechanical properties depending on the internal lattice structure as well as the internal filling rate. In a later study, we will find a new calculation algorithm that applies variables by FDM characteristics using the data obtained by printing the actual specimen.

Download Full-text

LATTICE OPTIMIZATION OF STRUCTURAL COMPONENTS USING NUMERICAL SIMULATIONS

Mechanical Testing and Diagnosis ◽

10.35219/mtd.2020.1.01 ◽

2020 ◽

Vol 10 (1) ◽

pp. 5-9

Author(s):

Florian VLĂDULESCU

Keyword(s):

Lattice Structure ◽

Lattice Structures ◽

Structural Components ◽

Design Constraints ◽

Lightweight Structures ◽

And Topology ◽

Lattice Materials ◽

Material Usage ◽

New Type ◽

Opening Up

In the last period of time, lattice structures have been developed as a new type of lightweight material. Significant amount of work has been done to investigate the applications and properties of lattice cells. In many fields of activity, lattice cells are widely used as support structures leading to minimal support material usage. This paper presents a method to design lattice structure of a bracket based on the modal analysis and topology optimization.Traditional design approaches do not make the most of new manufacturing methods, like additive manufacturing, which are removing design constraints and opening up new possibilities.The optimal shape of a part is often organic and counterintuitive, so designing it requires a different approach. Topology optimization allows for specifying where supports and loads are located on a volume of material and lets the software find the best shape. Designers can easily perform lightweight structures, extract CAD shapes and quickly verify the optimized design.In this study, it is optimized the distribution of orthotropic lattice materials inside the shape of the bracket, having as objective to maximize the first natural frequency and a response constraint to keep 40% of the bracket mass. Numerical results demonstrate remarkable structural properties of conforming lattice structures obtained.

Download Full-text

Investigation on Process-Properties Relationship with Mechanical Properties of Lattice-Structured Cellular Material for Lightweight Application

International Journal of Engineering & Technology ◽

10.14419/ijet.v7i3.17.16611 ◽

2018 ◽

Vol 7 (3.17) ◽

pp. 1

Author(s):

N A. Rosli ◽

R Hasan ◽

W H. Ng ◽

M K. Baharudin ◽

M R. Alkahari

Keyword(s):

Mechanical Properties ◽

Mechanical Performance ◽

Lattice Structure ◽

Testing Machine ◽

Lattice Structures ◽

Universal Testing ◽

Lightweight Structure ◽

Energy Absorbing ◽

Printing Machine ◽

Operational Time

Lattice structures possess exceptional mechanical strength resulting in highly efficient load supporting systems. The lattice structure has been receiving interest in a variety of application areas and industries such as automotive, shipping and aeronautic. The metallic or polymer micro lattice structure can be categorized as lightweight and energy-absorbing structure. These characteristics are best applied to transportation part where the lightweight structure will help reduce its overall weight, thus increase the operational time since energy and cost consumption is a big concern in the industry these days. The aim of this study is to investigate relationship between process-properties and mechanical performance of polymer lattice structure. The lattice structure was designed by using SolidWorks software and fabricated using CubePro 3D printing machine. Compression test was performed by Instron 5585 universal testing machine to analyse the strength of the lattice structure. It was found that lattice structure manufactured with the setting of solid print strength, honeycomb print pattern, 70 µm layer thickness and strut diameter of 2.4 mm possesses the optimum mechanical property.

Download Full-text