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 Octet-truss cellular materials for improved mechanical properties and specific energy absorption

2019 ◽  
Vol 173 ◽  
pp. 107773 ◽  
Author(s):  
Jian Song ◽  
Wenzhao Zhou ◽  
Yuejiao Wang ◽  
Rong Fan ◽  
Yinchu Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Energy Absorption ◽  
Specific Energy ◽  
Cellular Materials ◽  
Specific Energy Absorption ◽  
Octet Truss

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 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.

Effect of smoke treatment on flexural strength of bamboo hierarchical structure

BioResources ◽  
2020 ◽  
Vol 16 (1) ◽  
pp. 387-402
Author(s):  
Raviduth Ramful ◽  
Atsushi Sakuma
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Energy Absorption ◽  
Hierarchical Structure ◽  
Specific Energy ◽  
Construction Material ◽  
Tensile Load ◽  
Modulus Of Rupture ◽  
Specific Energy Absorption ◽  
Good Ability

Despite bamboo’s noteworthy durability, the incidental effects of smoke treatment on the mechanical properties of bamboo culms, including its underlying mechanisms, have not been fully investigated. This study investigated the effects of smoke treatment on the flexural strength of Madake bamboo’s (Phyllostachys bambusoides) hierarchical structure. Results in small clear specimens displayed an asymmetrical flexural behaviour regardless of the applied treatment, and the parameters of flexural strain and specific energy absorption, demonstrated by modulus of elasticity and modulus of rupture, were found to differ. Concerning compression, parenchyma cells had good ability to absorb large deformation, indicated by their large increase in specific energy absorption. In addition, a distinct difference was found between smoke-treated bamboo and untreated bamboo as the capacity of its outermost fibres to withstand greater tensile load was impaired, indicated by the reduction in flexural strain. Thermal degradation caused an increase in the hydrophobicity of bamboo’s outermost layers, thereby engendering higher brittleness in the smoked bamboo. This work highlights critical changes in the mechanical properties of smoked bamboo, which can be addressed in future studies to improve its strength as a sustainable construction material.

Mechanical Properties of High Strength Desert Sand Concrete

2015 ◽  
Vol 1095 ◽  
pp. 263-266
Author(s):  
Hai Feng Liu ◽  
Ju Rong Ma ◽  
Yun Long Chen ◽  
Deng Yang
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Energy Absorption ◽  
Specific Energy ◽  
High Strength ◽  
Experimental Results ◽  
Replacement Ratio ◽  
Specific Energy Absorption ◽  
Desert Sand

In order to research on the mechanical properties of high strength desert sand concrete, the compressive experiment of high strength desert sand concrete with different desert sand replacement ratio was carried out. The influence of desert sand replacement ratio on the compressive strength and specific energy absorption of high strength desert sand concrete was analyzed. Experimental results shows that the optimum desert sand replacement ratio is from 0 to 40%, which provides advice and guidance to the utility of high strength desert sand concrete in practice.

Dynamic Axial Compression of Square CFRP/Aluminium Tubes

2019 ◽  
Vol 794 ◽  
pp. 202-207
Author(s):  
Rafea Dakhil Hussein ◽  
Dong Ruan ◽  
Guo Xing Lu ◽  
Jeong Whan Yoon ◽  
Zhan Yuan Gao
Keyword(s):  
Energy Absorption ◽  
Specific Energy ◽  
Fibre Composite ◽  
Dynamic Tests ◽  
Carbon Fibre Composite ◽  
Specific Energy Absorption ◽  
Static Tests ◽  
Crushing Force ◽  
Cfrp Tubes ◽  
The Impact

Carbon fibre composite tubes have high strength to weight ratios and outstanding performance under axial crushing. In this paper, square CFRP tubes and aluminium sheet-wrapped CFRP tubes were impacted by a drop mass to investigate the effect of loading velocity on the energy absorption of CFRP/aluminium tubes. A comparison of the quasi-static and dynamic crushing behaviours of tubes was made in terms of deformation mode, peak crushing force, mean crushing force, energy absorption and specific energy absorption. The influence of the number of aluminium layers that wrapped square CFRP tubes on the crushing performance of tubes under axial impact was also examined. Experimental results manifested similar deformation modes of tubes in both quasi-static and dynamic tests. The dynamic peak crushing force was higher than the quasi-static counterpart, while mean crushing force, energy absorption and specific energy absorption were lower in dynamic tests than those in quasi-static tests. The mean crushing force and energy absorption decreased with the crushing velocity and increased with the number of aluminium layers. The impact stroke (when the force starts to drop) decreased with the number of aluminium layers.

Ballistic Performance Evaluation of Kevlar-Glass Fibre Hybrid Composite Laminate against Medium Velocity Impact

2021 ◽  
Vol 1165 ◽  
pp. 47-64
Author(s):  
Saurabh S. Kumar ◽  
Rajesh G. Babu ◽  
U. Magarajan
Keyword(s):  
Energy Absorption ◽  
Specific Energy ◽  
Glass Fibre ◽  
Hybrid Composite ◽  
Composite Laminates ◽  
Areal Density ◽  
Ballistic Performance ◽  
Performance Requirement ◽  
Specific Energy Absorption ◽  
Fabric Composite

In this paper, the post ballistic impact behaviour of kevlar-glass fibre hybrid composite laminates was investigated against 9×19 mm projectile. Eight different types of composite laminates with different ratios of kevlar woven fibre to glass fibre were fabricated using hand lay-up with epoxy matrix. Ballistic behaviour like ballistic Limit (V50), energy absorption, specific energy absorption and Back Face Signature (BFS) were studied after bullet impact. The results indicated that as the Percentage of glass fibre is increased there was a linear increment in the ballistic behaviour. Addition of 16% kevlar fabric, composite sample meets the performance requirement of NIJ0101.06 Level III-A. Since the maximum specific energy absorption was observed in Pure Kevlar samples and the adding of glass fibre increases the weight and Areal Density of the sample, further investigations need to be carried out to utilize the potential of glass fibre for ballistic applications.

Sign in / Sign up

Export Citation Format

Share Document