scholarly journals Comparative Study on the Uniaxial Behaviour of Topology-Optimised and Crystal-Inspired Lattice Materials

Metals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 491 ◽  
Author(s):  
Chengxing Yang ◽  
Kai Xu ◽  
Suchao Xie
Keyword(s):  
Elastic Modulus ◽  
Relative Density ◽  
Energy Absorption ◽  
Design Method ◽  
Deformation Mode ◽  
Topology Optimisation ◽  
Loading Direction ◽  
Collapse Strength ◽  
Lattice Materials ◽  
Cell Topology

This work comparatively studies the uniaxial compressive performances of three types of lattice materials, namely face-centre cube (FCC), edge-centre cube (ECC), and vertex cube (VC), which are separately generated by topology optimisation and crystal inspiration. High similarities are observed between the materials designed by these two methods. The effects of design method, cell topology, and relative density on deformation mode, mechanical properties, and energy absorption are numerically investigated and also fitted by the power law. The results illustrate that both topology-optimised and crystal-inspired lattices are mainly dominated by bending deformation mode. In terms of collapse strength and elastic modulus, VC lattice is stronger than FCC and ECC lattices because its struts are arranged along the loading direction. In addition, the collapse strength and elastic modulus of the topology-optimised FCC and ECC are close to those generated by crystal inspiration at lower relative density, but the topology-optimised FCC and ECC are obviously superior at a higher relative density. Overall, all topology-generated lattices outperform the corresponding crystal-guided lattice materials with regard to the toughness and energy absorption per unit volume.

scholarly journals Dynamic Mechanical Properties of Selective-laser-melting-processed Ti6Al4V

2021 ◽  
Author(s):  
Zhong-Hua Li ◽  
Zhicheng Yang ◽  
Bin Liu ◽  
Jia-Xin Li ◽  
Ze-Zhou Kuai ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Relative Density ◽  
Energy Absorption ◽  
Selective Laser Melting ◽  
Unit Cell ◽  
Laser Melting ◽  
Static Compression ◽  
Biological Compatibility ◽  
Sheet Structure

Abstract The relative density grading of metal lattice structures becomes a favourable design for bone plants since these structures are suitable for human implantation and have good biological compatibility. The unit cell structure designed using this method is better than that designed by traditional 3D modelling software, especially when using a bionic unit cell design created by a triple periodic minimum surface (TPMS). In this study, the manufacturability of Gyroids was tested by studying three different designs: the relative density of 30%, 20%, and 10% sheet structure. The main purpose is to understand the influence of relative density on the static compression performance of the sheet-like Gyroids structure. This study qualitatively analyses the influence of the relative density of the Gyroids lattice structure prepared by the selective laser melting technology on the compressive strength, elastic modulus, energy absorption and failure mechanism. As the relative density of the sheet structure decreases, the compressive strength decreases. The elastic modulus of the sheet structure of 10% is slightly higher than that of 20%, showing a different trend from the compressive strength. At the same time, the energy absorption per unit volume increases when the relative density decreases and becomes smaller, and the failure modes of the three relative densities all show a 45° fracture failure.

scholarly journals Design Method Using Response Surface Model for CFRP Corrugated Structure under Quasistatic Crushing

2021 ◽  
Vol 11 (21) ◽  
pp. 10178
Author(s):  
Tetsuya Gomi ◽  
Shotaro Ayuzawa ◽  
Yuta Urushiyama ◽  
Kazuhito Misaji ◽  
Susumu Takahashi ◽  
...  
Keyword(s):  
Response Surface ◽  
Energy Absorption ◽  
Design Method ◽  
Deformation Mode ◽  
High Energy ◽  
Absorption Efficiency ◽  
Response Surfaces ◽  
Surface Model ◽  
Development Period ◽  
Energy Absorption Efficiency

The development of a carbon-fiber-reinforced plastic (CFRP) part is carried out by utilizing many experimental results in deciding the design. For this reason, the development period of a CFRP structure is long and an obstacle for commercialization. In this paper, multiple regression analysis is used to derive a response surface that estimates the generated load using the shape parameters of a corrugated collision energy absorbing structure to shorten the development period. To obtain the response surface, we conducted a quasistatic crushing experiment by using the length of linear portions (pitch) and the number of stacks (thickness) of a corrugated shape as parameters. When progressive crushing mode is observed, energy absorption efficiency decreases with the increase in pitch, and increases with the increase in the number of stacks. To discuss how energy absorption efficiency changes, a comparison examination is conducted using the derived response surfaces. Results indicate that specifications with high energy absorption efficiency can be accurately selected using the response surface of primary expression. In addition, differences in deformation mode were due to the influence of the stress at the corner portion of a part.

The equivalent method of double V-wing honeycombs on the in-plane dynamic impact

2021 ◽  
pp. 073168442199086
Author(s):  
Yunfei Qu ◽  
Dian Wang ◽  
Hongye Zhang
Keyword(s):  
Mechanical Properties ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Elastic Modulus ◽  
Energy Absorption ◽  
Width Ratio ◽  
Size Factor ◽  
Dynamic Impact ◽  
Element Analysis ◽  
Equivalent Method

The double V-wing honeycomb can be applied in many fields because of its lower mass and higher performance. In this study, the volume, in-plane elastic modulus and unit cell area of the double V-wing honeycomb were analytically derived, which became parts of the theoretical basis of the novel equivalent method. Based on mass, plateau load, in-plane elastic modulus, compression strain and energy absorption of the double V-wing honeycomb, a novel equivalent method mapping relationship between the thickness–width ratio and the basic parameters was established. The various size factor of the equivalent honeycomb model was denoted as n and constructed by the explicit finite element analysis method. The mechanical properties and energy absorption performance for equivalent honeycombs were investigated and compared with hexagonal honeycombs under dynamic impact. Numerical results showed a well coincidence for each honeycomb under dynamic impact before 0.009 s. Honeycombs with the same thickness–width ratio had similar mechanical properties and energy absorption characteristics. The equivalent method was verified by theoretical analysis, finite element analysis and experimental testing. Equivalent honeycombs exceeded the initial honeycomb in performance efficiency. Improvement of performance and weight loss reached 173.9% and 13.3% to the initial honeycomb. The double V-wing honeycomb possessed stronger impact resistance and better load-bearing capacity than the hexagonal honeycomb under impact in this study. The equivalent method could be applied to select the optimum honeycomb based on requirements and improve the efficiency of the double V-wing honeycomb.

Energy Absorption of Origami Crash Box: Numerical Simulation and Theoretical Analysis

2018 ◽  
Author(s):  
Mengyan Shi ◽  
Jiayao Ma ◽  
Yan Chen ◽  
Zhong You
Keyword(s):  
Energy Absorption ◽  
Theoretical Study ◽  
Low Cost ◽  
Deformation Mode ◽  
Absorption Efficiency ◽  
Great Promise ◽  
Good Match ◽  
Energy Absorption Efficiency ◽  
Thin Walled ◽  
Initial Peak

Thin-walled tubes as energy absorption devices are widely in use for their low cost and high manufacturability. Employing origami technique on a tube enables induction of a predetermined failure mode so as to improve its energy absorption efficiency. Here we study the energy absorption of a hexagonal tubular device named the origami crash box numerically and theoretically. Numerical simulations of the quasi-static axial crushing show that the pattern triggers a diamond-shaped mode, leading to a substantial increase in energy absorption and reduction in initial peak force. The effects of geometric parameters on the performance of the origami crash box are also investigated through a parametric study. Furthermore, a theoretical study on the deformation mode and energy absorption of the origami crash box is carried out, and a good match with numerical results is obtained. The origami crash box shows great promise in the design of energy absorption devices.

Effect of polymer foam anisotropy on energy absorption during combined shear-compression loading

2017 ◽  
Vol 54 (3) ◽  
pp. 597-613 ◽  
Author(s):  
Yasmine Mosleh ◽  
Kelly Vanden Bosche ◽  
Bart Depreitere ◽  
Jos Vander Sloten ◽  
Ignaas Verpoest ◽  
...  
Keyword(s):  
Energy Absorption ◽  
Transverse Shear ◽  
Axial Loading ◽  
Expanded Polystyrene ◽  
Polystyrene Foam ◽  
Polymer Foam ◽  
Expanded Polystyrene Foam ◽  
Shear Loads ◽  
Loading Direction ◽  
Compression Behaviour

Polymeric foams are extensively used in applications such as packaging, sports goods and sandwich structures. Since in-service loading conditions are often multi-axial, characterisation of foams under multi-axial loading is essential. In this article, quasi-static combined shear-compression behaviour of isotropic expanded polystyrene foam and anisotropic polyethersulfone foam was studied. For this, a testing apparatus which can apply combined compression and transverse shear loads was developed. The results revealed that the shear and compression energy absorption, yield stress and stiffness of foams are dependent on deformation angle. The total energy absorption of the anisotropic polyethersulfone foam is shown to be direction dependent in contrast to isotropic expanded polystyrene. Furthermore, for similar relative density, polyethersulfone foam absorbs more energy than expanded polystyrene foam, regardless of deformation angle. This study highlights the importance of correct positioning of foam cells in anisotropic foams with respect to loading direction to maximise energy absorption capability.

scholarly journals Degradation of Mechanical Behavior of Sandstone under Freeze-Thaw Conditions with Different Low Temperatures

2021 ◽  
Vol 11 (22) ◽  
pp. 10653
Author(s):  
Jingwei Gao ◽  
Chao Xu ◽  
Yan Xi ◽  
Lifeng Fan
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Mechanical Behavior ◽  
Energy Absorption ◽  
Uniaxial Compressive Strength ◽  
Dynamic Strength ◽  
Freezing Temperature ◽  
P Wave ◽  
Freeze Thaw ◽  
P Wave Velocity

This study investigated the effects of freezing temperature under freeze-thaw cycling conditions on the mechanical behavior of sandstone. First, the sandstone specimens were subjected to 10-time freeze-thaw cycling treatments at different freezing temperatures (−20, −40, −50, and −60 °C). Subsequently, a series of density, ultrasonic wave, and static and dynamic mechanical behavior tests were carried out. Finally, the effects of freezing temperature on the density, P-wave velocity, stress–strain curves, static and dynamic uniaxial compressive strength, static elastic modulus, and dynamic energy absorption of sandstone were discussed. The results show that the density slightly decreases as temperature decreases, approximately by 1.0% at −60 °C compared with that at 20 °C. The P-wave velocity, static and dynamic uniaxial compressive strength, static elastic modulus, and dynamic energy absorption obviously decrease. As freezing temperature decreases from 20 to −60 °C, the static uniaxial compressive strength, static elastic modulus, dynamic strength, and dynamic energy absorption of sandstone decrease by 16.8%, 21.2%, 30.8%, and 30.7%, respectively. The dynamic mechanical behavior is more sensitive to the freezing temperature during freeze-thawing cycling compared with the static mechanical behavior. In addition, a higher strain rate can induce a higher dynamic strength and energy absorption.

The strength and dilatancy of sand

1992 ◽  
Vol 29 (3) ◽  
pp. 522-526 ◽  
Author(s):  
Y. P. Vaid ◽  
S. Sasitharan
Keyword(s):  
Relative Density ◽  
Triaxial Test ◽  
Friction Angle ◽  
Stress Path ◽  
Triaxial Tests ◽  
Confining Stress ◽  
Peak Friction Angle ◽  
Loading Direction ◽  
Dilation Rate ◽  
Unique Relationship

The effects of stress path and loading direction in the triaxial test on strength and dilatancy of sand are investigated. It is shown that the unique relationship observed between peak friction angle and dilation rate at peak in conventional triaxial tests is followed regardless of stress path, confining stress at failure, relative density, and the mode of loading (compression or extension). Key words : sand, peak friction angle, dilatancy, stress path, triaxial test.

Composite Core Cross Tube Crushing Analysis

2020 ◽  
Author(s):  
Sean Jenson ◽  
Muhammad Ali ◽  
Khairul Alam
Keyword(s):  
Energy Absorption ◽  
Compressive Loading ◽  
Deformation Mode ◽  
High Energy ◽  
Absorption Capacity ◽  
Functionally Graded ◽  
Layer By Layer ◽  
Thin Walled ◽  
The Cross ◽  
Energy Absorbing

Abstract Thin walled axial members are typically used in automobiles’ side and front chassis to improve crashworthiness of vehicles. Extensive work has been done in exploring energy absorbing characteristics of thin walled structural members under axial compressive loading. The present study is a continuation of the work presented earlier on evaluating the effects of inclusion of functionally graded cellular structures in thin walled members under axial compressive loading. A compact functionally graded composite cellular core was introduced inside a cross tube with side length and wall thickness of 25.4 mm and 3.048 mm, respectively. The parameters governing the energy absorbing characteristics such as deformation or collapsing modes, crushing/ reactive force, plateau stress level, and energy curves, were evaluated. The results showed that the inclusion of composite graded cellular structure increased the energy absorption capacity of the cross tube significantly. The composite graded structure underwent progressive stepwise, layer by layer, crushing mode and provided lateral stability to the cross tube thus delaying local tube wall collapse and promoting large localized folds on the tube’s periphery as compared to highly localized and compact deformation modes that were observed in the empty cross tube under axial compressive loading. The variation in deformation mode resulted in enhanced stiffness of the composite structure, and therefore, high energy absorption by the structure. This aspect has a potential to be exploited to improve the crashworthiness of automobile structures.

Mechanical performances of four lattice materials guided by topology optimisation

2020 ◽  
Vol 178 ◽  
pp. 339-345 ◽  
Author(s):  
Chengxing Yang ◽  
Ping Xu ◽  
Suchao Xie ◽  
Shuguang Yao
Keyword(s):  
Topology Optimisation ◽  
Lattice Materials ◽  
Mechanical Performances
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