Behaviour of Cellular Structures under Impact Loading a Computational Study

2007 ◽  
Vol 566 ◽  
pp. 53-60 ◽  
Author(s):  
Zoran Ren ◽  
Matej Vesenjak ◽  
Andreas Öchsner
Keyword(s):  
Relative Density ◽  
Impact Loading ◽  
Cellular Structure ◽  
Computational Models ◽  
Computational Study ◽  
Base Material ◽  
Cellular Structures ◽  
Open Cell ◽  
Closed Cell ◽  
Regular Open

New multiphysical computational models for simulation of regular open and closed-cell cellular structures behaviour under compressive impact loading are presented. The behaviour of cellular structures with fluid fillers under uniaxial impact loading and large deformations has been analyzed with the explicit nonlinear finite element code LS-DYNA. The behaviour of closed-cell cellular structure has been evaluated with the use of the representative volume element, where the influence of residual gas inside the closed pores has been studied. Open-cell cellular structure was modelled as a whole to properly account for considered fluid flow through the cells, which significantly influences macroscopic behaviour of cellular structure. The fluid has been modelled by applying a Smoothed Particle Hydrodynamics (SPH) method. Computational simulations showed that the base material has the highest influence on the behaviour of cellular structures under impact conditions. The increase of the relative density and strain rate results in increase of the cellular structure stiffness. Parametrical numerical simulations have also confirmed that filler influences the macroscopic behaviour of the cellular structures which depends on the loading type and the size of the cellular structure. In open-cell cellular structures with higher filler viscosity and higher relative density, increased impact energy absorption has been observed.

Thermal Post-Impact Behavior of Closed-Cell Cellular Structures with Fillers – Part I

2007 ◽  
Vol 553 ◽  
pp. 196-201 ◽  
Author(s):  
Matej Vesenjak ◽  
Andreas Öchsner ◽  
Zoran Ren
Keyword(s):  
Impact Loading ◽  
Thermal Conduction ◽  
Cellular Structure ◽  
Base Material ◽  
Impact Behavior ◽  
Cellular Structures ◽  
Strongly Coupled ◽  
Weakly Coupled ◽  
Closed Cell ◽  
Post Impact

The study describes the behavior of regular closed-cell cellular structure with gaseous fillers under impact conditions and consequent post-impact thermal conduction due to the compression of filler gas. Two dependent but different analyses types have been carried out for this purpose: (i) a strongly coupled fluid-structure interaction and (ii) a weakly coupled thermalstructural analysis. This paper describes the structural analyses of the closed-cell cellular structure under impact loading. The explicit code LS-DYNA was used to computationally determine the behavior of cellular structure under compressive dynamic loading, where one unit volume element of the cellular structure has been discretised with finite elements considering a simultaneous strongly coupled interaction with the gaseous pore filler. Closed-cell cellular structures with different relative densities and initial pore pressures have been considered. Computational simulations have shown that the gaseous filler influences the mechanical behavior of cellular structure regarding the loading type, relative density and type of the base material. It was determined that the filler’s temperature significantly increases due to the compressive impact loading, which might influence the macroscopic behavior of the cellular structure.

Numerical Prediction of the Effective Thermal Conductivity of Open- and Closed-Cell Foam Structures

2010 ◽  
Vol 297-301 ◽  
pp. 1210-1217 ◽  
Author(s):  
Seyed Mohammad Hossein Hosseini ◽  
Andreas Öchsner ◽  
Thomas Fiedler
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Relative Density ◽  
Effective Thermal Conductivity ◽  
Linear Trend ◽  
Space Filling ◽  
Open Cell ◽  
Cell Structures ◽  
Closed Cell ◽  
Cell Foam

This paper investigates the thermal properties of metallic open-cell and closed-cell foam structures in space filling and non-space filling configurations. In both, i.e. open-cell and closed-cell structures, a linear trend depending on the relative density has been reported. However the closed-cell structures compared to open-cell ones have a higher thermal conductivity for the same relative density.

scholarly journals The Effect of Microcellular Structure on the Dynamic Mechanical Thermal Properties of High-Performance Nanocomposite Foams Made of Graphene Nanoplatelets-Filled Polysulfone

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 437
Author(s):  
Marcelo Antunes ◽  
Hooman Abbasi ◽  
José Ignacio Velasco
Keyword(s):  
Relative Density ◽  
Supercritical Co2 ◽  
Cellular Structure ◽  
High Performance ◽  
Graphene Nanoplatelets ◽  
Cellular Structures ◽  
Density Range ◽  
Specific Storage ◽  
Glass Transition Temperatures ◽  
Nanocomposite Foams

Polysulfone nanocomposite foams containing variable amounts of graphene nanoplatelets (0–10 wt%) were prepared by water vapor-induced phase separation (WVIPS) and supercritical CO2 (scCO2) dissolution. WVIPS foams with two ranges of relative densities were considered, namely, between 0.23 and 0.41 and between 0.34 and 0.46. Foams prepared by scCO2 dissolution (0.0–2.0 wt% GnP) were obtained with a relative density range between 0.35 and 0.45. Although the addition of GnP affected the cellular structure of all foams, they had a bigger influence in WVIPS foams. The storage modulus increased for all foams with increasing relative density and GnP’s concentration, except for WVIPS PSU-GnP foams, as they developed open/interconnected cellular structures during foaming. Comparatively, foams prepared by scCO2 dissolution showed higher specific storage moduli than similar WVIPS foams (same relative density and GnP content), explained by the microcellular structure of scCO2 foams. As a result of the plasticizing effect of CO2, PSU foams prepared by scCO2 showed lower glass transition temperatures than WVIPS foams, with the two series of these foams displaying decreasing values with incrementing the amount of GnP.

scholarly journals Design and Optimization of Graded Cellular Structures With Triply Periodic Level Surface-Based Topological Shapes

2019 ◽  
Vol 141 (7) ◽  
Author(s):  
Dawei Li ◽  
Ning Dai ◽  
Yunlong Tang ◽  
Guoying Dong ◽  
Yaoyao Fiona Zhao
Keyword(s):  
Density Distribution ◽  
Relative Density ◽  
Cellular Structure ◽  
Scaling Laws ◽  
Functionally Graded ◽  
Cellular Structures ◽  
Level Surface ◽  
Implicit Functions ◽  
Design And Optimization ◽  
Triply Periodic

Periodic cellular structures with excellent mechanical properties widely exist in nature. A generative design and optimization method for triply periodic level surface (TPLS)-based functionally graded cellular structures is developed in this work. In the proposed method, by controlling the density distribution, the designed TPLS-based cellular structures can achieve better structural or thermal performances without increasing its weight. The proposed technique can be divided into four steps. First, the modified 3D implicit functions of the triply periodic minimal surfaces are developed to design different types of cellular structures parametrically and generate spatially graded cellular structures. Second, the numerical homogenization method is employed to calculate the elastic tensor and the thermal conductivity tensor of the cellular structures with different densities. Third, the optimal relative density distribution of the object is computed by the scaling laws of the TPLS-based cellular structures added optimization algorithm. Finally, the relative density of the numerical results of structure optimization is mapped into the modified parametric 3D implicit functions, which generates an optimum lightweight cellular structure. The optimized results are validated subjected to different design specifications. The effectiveness and robustness of the obtained structures is analyzed through finite element analysis and experiments. The results show that the functional gradient cellular structure is much stiffer and has better heat conductivity than the uniform cellular structure.

Numerical Investigation of the Thermal Properties of Irregular Foam Structures

2011 ◽  
Vol 312-315 ◽  
pp. 941-946 ◽  
Author(s):  
Seyed Mohammad Hossein Hosseini ◽  
A. Kharaghani ◽  
Christoph Kirsch ◽  
Andreas Öchsner
Keyword(s):  
Thermal Conductivity ◽  
Thermal Expansion ◽  
Thermal Properties ◽  
Relative Density ◽  
Metal Foams ◽  
Foam Structure ◽  
Open Cell ◽  
Closed Cell ◽  
Effective Thermal Expansion ◽  
Degree Of Irregularity

The thermal properties of irregular open-cell and closed-cell metal foams are investigated via numerical simulation. The influence of relative density and cell irregularity on the thermal conductivity and thermal expansion of the foam structure is determined. It is concluded that the effective thermal conductivity of the foam structure depends linearly on the relative density, whereas no dependence on the degree of irregularity is observed. The effective thermal expansion coefficient of the foam structure is constant for the range of parameters considered.

Equivalent Elastic Modulus of the Open-Cell Cellular Solids

2010 ◽  
Vol 34-35 ◽  
pp. 1501-1505
Author(s):  
Ying An Kang ◽  
Jia Cai Tan
Keyword(s):  
Relative Density ◽  
Geometrical Structure ◽  
Three Dimensional ◽  
Cellular Structures ◽  
Cellular Solids ◽  
Aluminum Foams ◽  
Open Cell ◽  
Prism Model ◽  
Theoretical Results ◽  
Good Agreement

The useful properties of cellular solids depend on the material from which they are made, their relative density, and their internal geometrical structure. Based on two simple models (two-dimensional honeycomb and three-dimensional prism)of cellular structures, equivalent Young’s modulus related to the relative density is derived, and the theoretical results are found to be in good agreement with experimental data of open cell aluminum foams. And the results provide evidence that the three-dimensional prism model is reasonable, which two models are approximately true at low density.

Thermal Post-Impact Behavior of Closed-Cell Cellular Structures with Fillers – Part II

2007 ◽  
Vol 553 ◽  
pp. 202-207 ◽  
Author(s):  
Matej Vesenjak ◽  
Zoran Žunič ◽  
Andreas Öchsner ◽  
Zoran Ren
Keyword(s):  
Heat Conduction ◽  
Temperature Increase ◽  
Cellular Structure ◽  
Base Material ◽  
Strongly Coupled ◽  
Weakly Coupled ◽  
Gas Compression ◽  
Closed Cell ◽  
Wide Range ◽  
Post Impact

The paper describes the post-impact thermal conduction of regular closed-cell cellular structure with gaseous fillers due to the dynamic compression. Two different but subsequent computational analyses have been carried out for this purpose. To define the behavior of the cellular structure under compressive dynamic loading, a unit volume element of the cellular structure has been analyzed with the explicit finite element code LS-DYNA by considering a strongly coupled interaction of the cellular structure base material with the gaseous pore filler. The resulting deformed cellular structure has then been imported in the finite volume code ANSYS CFX 10.0 for further weakly coupled thermal-structural analyses of post-impact heat conduction through the base material and filler gas. The increased temperature and pressure of the filler gas after compressive impact loading from the initial analyses have been used as initial conditions for the thermal analyses, where only the heat conduction due to the gas compression has been taken into account. This paper considers only the closed-cell cellular structure with two different relative densities and air inside the pores. Computational simulations have shown a low overall temperature increase of the cellular structure due to filler gas compression. The temperature increase of the base material is expected to be higher at lower relative densities. The presented procedure illustrates a convenient approach to solving strongly coupled fluid-structure interaction problems by considering also a weakly coupled thermal-structural solution, which can be used for a wide range of engineering applications.

Microstructure and calorimetric behavior of laser welded open cell foams in CuZnAl shape memory alloy

2016 ◽  
Vol 09 (06) ◽  
pp. 1642007 ◽  
Author(s):  
Carlo Alberto Biffi ◽  
Barbara Previtali ◽  
Ausonio Tuissi
Keyword(s):  
Shape Memory ◽  
Smart Materials ◽  
Cellular Structure ◽  
Base Material ◽  
Damping Capacity ◽  
Open Cell ◽  
Open Cell Foams ◽  
Compositional Variations ◽  
Alloy Softening ◽  
Stiffness And Damping

Cellular shape memory alloys (SMAs) are very promising smart materials able to combine functional properties of the material with lightness, stiffness, and damping capacity of the cellular structure. Their processing with low modification of the material properties remains an open question. In this work, the laser weldability of CuZnAl SMA in the form of open cell foams was studied. The cellular structure was proved to be successfully welded in lap joint configuration by using a thin plate of the same alloy. Softening was seen in the welded bead in all the investigated ranges of process speed as well as a double stage heat affected zone was identified due to different microstructures; the martensitic transformation was shifted to higher temperatures and the corresponding peaks were sharper with respect to the base material due to the rapid solidification of the material. Anyways, no compositional variations were detected in the joints.

Computational Study of Heat Transfer in Honeycomb Structures Accounting for Gaseous Pore Filler

2008 ◽  
Vol 273-276 ◽  
pp. 699-706 ◽  
Author(s):  
Matej Vesenjak ◽  
Zoran Žunič ◽  
Zoran Ren ◽  
Andreas Öchsner
Keyword(s):  
Heat Transfer ◽  
Thermal Properties ◽  
Heat Conduction ◽  
Relative Density ◽  
Cell Shape ◽  
Computational Study ◽  
Base Material ◽  
Honeycomb Structures ◽  
Ansys Cfx ◽  
Cell Shapes

Thermal properties of honeycomb structures with different cell shapes are investigated in this paper. The influence of cell shape, relative density and pore gases on the macroscopic honeycomb thermal properties is investigated by means of transient dynamic computational simulations. The ANSYS CFX code is used to evaluate the heat conduction trough the base material and the filler gas, as well as the convection in gas filler. The computational results clearly show a strong influence of the filler gas on heat conduction and macroscopic thermal properties of analyzed honeycomb structures, which is attributed to low relative density of the cellular structure. Additionally, the influence of considered relative densities is more prominent than the influence of cell shape. The evaluated results are valuable for further development of homogenization models of heat transfer in honeycomb structures accounting for gaseous pore fillers.

Sign in / Sign up

Export Citation Format

Share Document