scholarly journals Evaluating Lattice Mechanical Properties for Lightweight Heat-Resistant Load-Bearing Structure Design

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4786
Author(s):  
Xinglong Wang ◽  
Cheng Wang ◽  
Xin Zhou ◽  
Di Wang ◽  
Mingkang Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Topology Optimization ◽  
Porous Structure ◽  
Relative Density ◽  
Deformation Behavior ◽  
Optimization Design ◽  
Engineering Practice ◽  
Lattice Structures ◽  
Load Bearing ◽  
Heat Resistant

Heat-resistant, load-bearing components are common in aircraft, and they have high requirements for lightweight and mechanical performance. Lattice topology optimization can achieve high mechanical properties and obtain lightweight designs. Appropriate lattice selection is crucial when employing the lattice topology optimization method. The mechanical properties of a structure can be optimized by choosing lattice structures suitable for the specific stress environment being endured by the structural components. Metal lattice structures exhibit excellent unidirectional load-bearing performance and the triply periodic minimal surface (TPMS) porous structure can satisfy multi-scale free designs. Both lattice types can provide unique advantages; therefore, we designed three types of metal lattices (body-centered cubic (BCC), BCC with Z-struts (BCCZ), and honeycomb) and three types of TPMS lattices (gyroid, primitive, and I-Wrapped Package (I-WP)) combined with the solid shell. Each was designed with high level of relative density (40%, 50%, 60%, 70%, and 80%), which can be directly used in engineering practice. All test specimens were manufactured by selective laser melting (SLM) technology using Inconel 718 superalloy as the material and underwent static tensile testing. We found that the honeycomb test specimen exhibits the best strength, toughness, and stiffness properties among all structures evaluated, which is especially suitable for the lattice topology optimization design of heat-resistant, unidirectional load-bearing structures within aircraft. Furthermore, we also found an interesting phenomenon that the toughness of the primitive and honeycomb porous test specimens exhibited sudden increases from 70% to 80% and from 50% to 60% relative density, respectively, due to their structural characteristics. According to the range of the exponent value n and the deformation laws of porous structures, we also concluded that a porous structure would exhibit a stretching-dominated deformation behavior when exponent value n < 0.3, a bending-dominated deformation behavior when n > 0.55, and a stretching-bending-dominated deformation behavior when 0.3 < n < 0.55. This study can provide a design basis for selecting an appropriate lattice in lattice topology optimization design.

A Novel Design Method for Nonuniform Lattice Structures Based on Topology Optimization

2018 ◽  
Vol 140 (9) ◽  
Author(s):  
Yafeng Han ◽  
Wen Feng Lu
Keyword(s):  
Mechanical Properties ◽  
Topology Optimization ◽  
Relative Density ◽  
Common Ground ◽  
Lattice Structure ◽  
Design Method ◽  
Lattice Structures ◽  
Structural Wall ◽  
Unit Cells ◽  
The Common

Lattice structures are broadly used in lightweight structure designs and multifunctional applications. Especially, with the unprecedented capabilities of additive manufacturing (AM) technologies and computational optimization methods, design of nonuniform lattice structures has recently attracted great research interests. To eliminate constraints of the common “ground structure approaches” (GSAs), a novel topology optimization-based method is proposed in this paper. Particularly, the structural wall thickness in the proposed design method was set as uniform for better manufacturability. As a solution to carry out the optimized material distribution for the lattice structure, geometrical size of each unit cell was set as design variable. The relative density model, which can be obtained from the solid isotropic microstructure with penalization (SIMP)-based topology optimization method, was mapped into a nonuniform lattice structure with different size cells. Finite element analysis (FEA)-based homogenization method was applied to obtain the mechanical properties of these different size gradient unit cells. With similar mechanical properties, elements with different “relative density” were translated into unit cells with different size. Consequently, the common topology optimization result can be mapped into a nonuniform lattice structure. This proposed method was computationally and experimentally validated by two different load-support design cases. Taking advantage of the changeable surface-to-volume ratio through manipulating the cell size, this method was also applied to design a heat sink with optimum heat dissipation efficiency. Most importantly, this design method provides a new perspective to design nonuniform lattice structures with enhanced functionality and manufacturability.

THE RANDOM POROUS STRUCTURE AND MECHANICAL RESPONSE OF LIGHTWEIGHT ALUMINUM FOAMS

2014 ◽  
Vol 1662 ◽  
Author(s):  
Max Larner ◽  
John Acker ◽  
Lilian P. Dávila
Keyword(s):  
Mechanical Properties ◽  
Porous Structure ◽  
Relative Density ◽  
Testing Machine ◽  
Sound Insulation ◽  
Full Potential ◽  
Open Cell ◽  
Compressive Loads ◽  
Al Foam ◽  
Al Foams

ABSTRACTLightweight porous foams have been of particular interest in recent years, since they have a very unique set of properties which can be significantly different from their solid parent materials. These properties arise from their random porous structure which is generated through specialized processing techniques. Their unique structure gives these materials interesting properties which allow them to be used in diverse applications. In particular, highly porous Al foams have been used in aircraft components and sound insulation; however due to the difficulty in processing and the random nature of the foams, they are not well understood and thus have not yet been utilized to their full potential. The objective of this study was to integrate experiments and simulations to determine whether a relationship exists between the relative density (porous density/bulk density) and the mechanical properties of open-cell Al foams. Compression experiments were performed using an Instron Universal Testing Machine (IUTM) on ERG Duocel open-cell Al foams with 5.8% relative density, with compressive loads ranging from 0-6 MPa. Foam models were generated using a combination of an open source code, Voro++, and MATLAB. A Finite Element Method (FEM)-based software, COMSOL Multiphysics 4.3, was used to simulate the mechanical behavior of Al foam structures under compressive loads ranging from 0-2 MPa. From these simulated structures, the maximum von Mises stress, volumetric strain, and other properties were calculated. These simulation results were compared against data from compression experiments. CES EduPack software, a materials design program, was also used to estimate the mechanical properties of open-cell foams for values not available experimentally, and for comparison purposes. This program allowed for accurate prediction of the mechanical properties for a given percent density foam, and also provided a baseline for the Al foam samples tested via the IUTM method. Predicted results from CES EduPack indicate that a 5.8% relative density foam will have a Young’s Modulus of 0.02-0.92 GPa while its compressive strength will be 0.34-3.37 MPa. Overall results revealed a relationship between pores per inch and selected mechanical properties of Al foams. The methods developed in this study can be used to efficiently generate open-cell foam models, and to combine experiments and simulations to calculate structure-property relationships and predict yielding and failure, which may help in the pursuit of simulation-based design of metallic foams. This study can help to improve the current methods of characterizing foams and porous materials, and enhance knowledge about theirproperties for novel applications.

Mechanical properties and deformation behavior of additively manufactured lattice structures of stainless steel

2018 ◽  
Vol 145 ◽  
pp. 205-217 ◽  
Author(s):  
Patrick Köhnen ◽  
Christian Haase ◽  
Jan Bültmann ◽  
Stephan Ziegler ◽  
Johannes Henrich Schleifenbaum ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Deformation Behavior ◽  
Lattice Structures

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

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.

scholarly journals Dual Graded Lattice Structures: Generation Framework and Mechanical Properties Characterization

Polymers ◽  
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.

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

Materials ◽  
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.

An Innovative Design Based on CAD Environment

2011 ◽  
Vol 308-310 ◽  
pp. 1166-1169 ◽  
Author(s):  
Zhi Hao Zuo ◽  
Mike Xie ◽  
Bang Zhao
Keyword(s):  
Topology Optimization ◽  
Optimization Design ◽  
Industrial Design ◽  
Numerical Procedure ◽  
Optimal Solution ◽  
Optimization Procedure ◽  
Engineering Practice ◽  
Structural Topology ◽  
Software Interfaces ◽  
Design Integration

The mathematical development of structural topology optimization provides a mature tool for design optimization, although the application is still very limited in engineering practice. This paper intends to study the application of topology optimization in industrial design via commercial CAD software interfaces. An innovative numerical procedure for this purpose is introduced based on convenient CAD modeling interfaces. As an instance, the B-spline based environment Rhinoceros3D features the modeling module for the optimization procedure, in collaboration with an additional optimization engine BESO3D. The topology optimization is realized based on the CAD model from Rhinoceros and outputs the optimal solution into Rhinoceros after computation. Further interpretation of the optimization results is discussed within the framework of Rhinoceros. Design applications of the modeling-optimization design integration are showcased as the examples to demonstrate the efficiency and robustness of topology optimization in industrial design.

scholarly journals Optimal design of three-dimensional non-uniform nylon lattice structures for selective laser sintering manufacturing

2018 ◽  
Vol 10 (7) ◽  
pp. 168781401879083 ◽  
Author(s):  
Xin Jin ◽  
Guo Xi Li ◽  
Meng Zhang
Keyword(s):  
Mechanical Properties ◽  
Topology Optimization ◽  
Optimal Design ◽  
Cell Size ◽  
Selective Laser Sintering ◽  
Three Dimensional ◽  
Laser Sintering ◽  
Manufacturing Constraints ◽  
Lattice Structures ◽  
Cell Type

As a kind of novel multifunctional structure with three-dimensional pores characterized by low relative density, lattice structures can attain a lightweight design while maintaining high specific mechanical properties in three-dimensional solid structures. Focusing on the challenge of finding the optimal design of lattice structures in the design object, a design and modeling method of non-uniform three-dimensional lattice structures is proposed while ensuring the selective laser sintering manufacturability. Optimization for cell type, cell size, and strut size distribution of lattices is specified with the mechanical properties analyzed and the material model calculated beforehand. The manufacturing constraints are analyzed and expressed in topology optimization and the optimal distribution of topology optimization results is mapped to the strut size distribution of lattice cells. The rapid and automatic computer-aided design modeling of optimized structures is realized by the parametric definition and assembling of lattice components. Finally, the non-uniform structures are successfully manufactured by selective laser sintering and it is shown by means of finite element analysis and experiments that the proposed design approach can improve the mechanical performance compared to the uniform lattice structure under the same weight reduction. And for the design object in this study, body-centered structure with cell size [Formula: see text]mm is chosen as the optimal cell type and cell size under the given selective laser sintering manufacturing constraints.

Sign in / Sign up

Export Citation Format

Share Document