Influences of Material and Geometry in the Performance of Auxetic Composite Structure under Blast Loading

2016 ◽  
Vol 846 ◽  
pp. 476-481 ◽  
Author(s):  
Gabriele Imbalzano ◽  
Phuong Tran ◽  
Peter V.S. Lee ◽  
Dayalan Gunasegaram ◽  
Tuan D. Ngo
Keyword(s):  
Numerical Model ◽  
Blast Loading ◽  
General Linear Model ◽  
Composite Panel ◽  
Taguchi Design Of Experiment ◽  
The Core ◽  
Cellular Composite ◽  
Auxetic Structures ◽  
Statistical Studies ◽  
Auxetic Structure

This paper aims at investigating the deformation and damage mechanisms of auxetic sandwich panels subjected to localised blast. The ability of self-densifying and adjusting to the loads, typical of auxetic structures, has been evaluated. A numerical model of the auxetic cellular composite panel has been developed to conduct statistical studies on different parameters (core geometry and material) using Taguchi design of experiment (DOE) method combined with general linear model (GLM) for analysis of variance (ANOVA). The optimisation has been conducted evaluating different parameters: energy absorption of the entire panel and deformation of the back facet were measured. The analysis of the numerical model of the core suggests the importance of the self-adapting mechanism of the auxetic structure under blast loading.

scholarly journals Acoustic Panels Made of Paper Sludge and Clay Composites

2021 ◽  
Vol 13 (2) ◽  
pp. 637
Author(s):  
Tomas Astrauskas ◽  
Tomas Januševičius ◽  
Raimondas Grubliauskas
Keyword(s):  
Absorption Coefficient ◽  
Sound Absorption ◽  
Composite Panel ◽  
Sound Absorption Coefficient ◽  
Core Material ◽  
Paper Sludge ◽  
Frequency Range ◽  
Absorption Properties ◽  
Air Gaps ◽  
The Core

Studies on recycled materials emerged during recent years. This paper investigates samples’ sound absorption properties for panels fabricated of a mixture of paper sludge (PS) and clay mixture. PS was the core material. The sound absorption was measured. We also consider the influence of an air gap between panels and rigid backing. Different air gaps (50, 100, 150, 200 mm) simulate existing acoustic panel systems. Finally, the PS and clay composite panel sound absorption coefficients are compared to those for a typical commercial absorptive ceiling panel. The average sound absorption coefficient of PS-clay composite panels (αavg. in the frequency range from 250 to 1600 Hz) was up to 0.55. The resulting average sound absorption coefficient of panels made of recycled (but unfinished) materials is even somewhat higher than for the finished commercial (finished) acoustic panel (αavg. = 0.51).

scholarly journals 4D Printing of NiTi Auxetic Structure with Improved Ballistic Performance

Micromachines ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 745
Author(s):  
Hany Hassanin ◽  
Alessandro Abena ◽  
Mahmoud Ahmed Elsayed ◽  
Khamis Essa
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
Analytical Model ◽  
Poisson’S Ratio ◽  
Poisson's Ratio ◽  
4D Printing ◽  
Auxetic Structures ◽  
Negative Poisson's Ratio ◽  
The Impact ◽  
Auxetic Structure

Auxetic structures have attracted attention in energy absorption applications owing to their improved shear modulus and enhanced resistance to indentation. On the other hand, four-dimensional (4D) printing is an emerging technology that is capable of 3D printing smart materials with additional functionality. This paper introduces the development of a NiTi negative-Poisson’s-ratio structure with superelasticity/shape memory capabilities for improved ballistic applications. An analytical model was initially used to optimize the geometrical parameters of a re-entrant auxetic structure. It was found that the re-entrant auxetic structure with a cell angle of −30° produced the highest Poisson’s ratio of −2.089. The 4D printing process using a powder bed fusion system was used to fabricate the optimized NiTi auxetic structure. The measured negative Poisson’s ratio of the fabricated auxetic structure was found in agreement with both the analytical model and the finite element simulation. A finite element model was developed to simulate the dynamic response of the optimized auxetic NiTi structure subjected to different projectile speeds. Three stages of the impact process describing the penetration of the top plate, auxetic structure, and bottom plate have been identified. The results show that the optimized auxetic structures affect the dynamic response of the projectile by getting denser toward the impact location. This helped to improve the energy absorbed per unit mass of the NiTi auxetic structure to about two times higher than that of the solid NiTi plate and five times higher than that of the solid conventional steel plate.

3D Numerical Simulation and PEPT Experimental Investigation of Pressurized Gas-Solid Fluidized Bed Hydrodynamic

2009 ◽  
Author(s):  
P. Fede ◽  
G. Moula ◽  
A. Ingram ◽  
T. Dumas ◽  
O. Simonin
Keyword(s):  
Numerical Model ◽  
Fluidized Bed ◽  
Particle Velocity ◽  
Particle Trajectory ◽  
Wall Region ◽  
3 Dimensional ◽  
The Core ◽  
Numerical Predictions ◽  
Model Predictions ◽  
Good Agreement

The present paper is dedicated to numerical and experimental study of the hydrodynamic of a non-reactive isothermal pressurized fluidized bed. Experimental data have been obtained using PEPT technique allowing to track a particle trajectory inside a dense fluidized bed. A specific post-processing approach has been developed to compute the Eulerian time-averaged particle velocity field. The comparison with 3-dimensional numerical model predictions shows a good agreement in the core of the fluidized bed. In contrast, in the near wall region the numerical model overestimate the downward particle velocity. The modification of particle phase wall boundary condition improves the numerical predictions.

Hierarchical anisogrid stiffened composite panel subjected to blast loading: Equivalent theory

2018 ◽  
Vol 187 ◽  
pp. 259-268 ◽  
Author(s):  
Bei Zhang ◽  
Fengnian Jin ◽  
Zheng Zhao ◽  
Zhongxin Zhou ◽  
Ying Xu ◽  
...  
Keyword(s):  
Blast Loading ◽  
Composite Panel ◽  
Equivalent Theory

Mechanical Properties of Interlocking Cell Structure for Soft Exoskeleton Suits

2019 ◽  
Author(s):  
Dongchan Lee ◽  
Chulho Yang
Keyword(s):  
Structural Characteristics ◽  
Cell Structure ◽  
Human Motion ◽  
Cellular Structures ◽  
Lightweight Construction ◽  
Design Considerations ◽  
Auxetic Structures ◽  
3D Printers ◽  
Energy Absorbing ◽  
Auxetic Structure

Abstract This paper presents design considerations of an adjustable flexible auxetic structure used in soft wearable suits with a Cross Chiral Honeycomb (CCH) structure. In order to design a macro-auxetic structure with elastic flexibilities in the soft wearable suit, it is important to develop an auxetic unit cell with adjustability of stiffness. Airbag inflation and deflation mechanisms on the adjustable stiffness pads with auxetic foam play key roles in either the protection of the human body or the assistance of human motion through the reversible configurations of the structure. Periodic cellular structures used in auxetic foam were first considered in the field of lightweight construction due to their high specific stiffness, damping, and energy absorbing properties. The development of new manufacturing processes, especially the development of modern 3D-printers, has allowed the creation of 3D auxetic structures. Experiments of several specimens were conducted to verify mechanical structural characteristics of a CCH structure. Through this approach, valid geometric parameters of the macro-auxetic structure used in the soft wearable suit could be designated.

scholarly journals Thorium based fuel loading pattern for PWR reactor

2019 ◽  
Vol 108 ◽  
pp. 01028 ◽  
Author(s):  
Mikolaj Oettingen
Keyword(s):  
Monte Carlo ◽  
Numerical Model ◽  
Pressurized Water Reactor ◽  
Fuel Management ◽  
Fuel Loading ◽  
Pressurized Water ◽  
Loading Pattern ◽  
The Core ◽  
Continuous Energy ◽  
Numerical Tools

The Monte Carlo Continuous Energy Burnup Code was used for numerical simulations of the pressurized water reactor (PWR) with mixed U-Th fuel. The thorium fuel was introduce to the core of the Westinghouse 4-loop PWR in order to investigate the time evolutions of fissile 233U, 235U, 239Pu, 241Pu and of fertile 232Th and 238U. The core loading pattern was designed using the Whole Assembly Seed and Blanket (WASB) approach. The following calculations show the feasibility of the proposed incore fuel management patter using the available numerical tools, developed numerical model and methods.

The manufacture and characterization of composite three-dimensional re-entrant auxetic cellular structures made from carbon fiber reinforced polymer

2018 ◽  
Vol 52 (23) ◽  
pp. 3265-3273 ◽  
Author(s):  
Xin-Tao Wang ◽  
Yun-Long Chen ◽  
Li Ma
Keyword(s):  
Finite Element ◽  
Carbon Fiber ◽  
Three Dimensional ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Reinforced Polymer ◽  
Auxetic Structures ◽  
Carbon Fiber Reinforced ◽  
Auxetic Structure

In recent years, three-dimensional auxetic structures have attracted great interest. Generally, three-dimensional auxetic structures are of complicate geometries which make them difficult to fabricate, benefiting from the development of additive manufacturing technologies, many three-dimensional auxetic structures can be made from metals or polymers. However, to the authors' knowledge, the additive manufacturing technology of fiber reinforced polymer is not fully developed, and none three-dimensional auxetic structure made from fiber reinforced polymer has been reported before. To integrate the high specific stiffness, high specific strength, and light weight merits of high-performance fiber reinforced polymer composites into three-dimensional auxetic structures with unique properties, research on composite three-dimensional auxetic structures made from fiber reinforced polymer should be conducted. This paper presents the composite three-dimensional re-entrant auxetic structures made from carbon fiber reinforced polymer laminates using an interlocking assembly method. The auxetic nature of the composite structure has been verified by experimental testing and finite element simulations. Based on the finite element models, the dependences of the Poisson's ratio and effective compression modulus of the composite auxetic three-dimensional re-entrant structure on the re-entrant angle have been studied and compared to metal three-dimensional re-entrant structure. A comparative study of the Poisson's ratio and specific stiffness of carbon fiber reinforced polymer composite auxetic structure with the three-dimensional printed polymer and metal auxetic structures in literature has also been conducted.

DIFFERENT FAILURE MODES ASSESSMENT TO IMPROVE THE SANDWICH COMPOSITE PANEL STIFFNESS WITH HONEYCOMB CORE FOR MARINE STRUCTURES APPLICATION

2016 ◽  
Vol 78 (11) ◽  
Author(s):  
Mehdi Nakisa ◽  
Fatemeh Behrouzi ◽  
Ahmad Mobasher Amini
Keyword(s):  
Failure Modes ◽  
Compressive Load ◽  
Composite Panel ◽  
Face Sheet ◽  
Core Material ◽  
Sandwich Composite ◽  
Carbon Fiber Composites ◽  
Honeycomb Core ◽  
Marine Structures ◽  
The Core

This research paper focuses on the prediction of different failure modes to improve the sandwich composite panel with honeycomb core for application in marine structures. Marine, automotive and aerospace industries are continually trying to optimize material performance in terms of strength and weight. Success has been achieved through the growth of high performance materials, including fibrous composites such as ceramics, new alloys, and carbon fiber composites and through the use of structural concepts such as sandwich composite panel construction. Sandwich composite panel construction with honeycomb core consists of three components: two facing sheets, the core that fill the space between the facing sheet and the core-to-facing bonding adhesives. The facing sheets of a sandwich panel can be compared to the flanges of an I-beam element, as they carry the bending stresses to which the beam is subjected. With one facing sheet in compression, the other is in tension. Similarly the honeycomb core corresponds to the web of the I-beam that resists the shear loads and vertical compressive load to the face sheet. This paper presents a model for prediction of different failure mode of face sheet and core material. The obtained results of this model were compared with experimental results and presents that it is a simple and good model.  

scholarly journals TENSIONED AUXETIC STRUCTURES MANUAL CALCULUS

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Mª Dolores Álvarez Elipe
Keyword(s):  
Detailed Analysis ◽  
Experimental Model ◽  
Structural Characteristics ◽  
Structural Systems ◽  
Structure Model ◽  
Structural Evaluation ◽  
Auxetic Materials ◽  
Application Techniques ◽  
Auxetic Structures ◽  
Auxetic Structure

Auxetic materials have several properties very useful to be applied to architecture structures. This paper is aimed to test structurally a specific auxetic structure model. This hypothesis will be check: if auxetic materials have innovative properties in nanoscale then they will also have these properties in macroscale. But there are some differences for these different scales. In the nanoscale auxetic structures have rigid knots with flexible bars, but in the scale of architecture they will have articulated knots and a cable that stabilizes the set.A unity of the hexagonal re-entrant structure will be tested in order to obtain their structural characteristics. The application of this structure and their behavior in architecture are not yet known, that’s why this auxetic model will become an experimental model to establish a structural evaluation of one of the most innovative auxetic geometries, to apply to the construction of new architectures. The results of research and investigation will become apparent by their structural evaluation, through the utilization of manual calculus.The re-entrant hexagonal geometry provides a strong foundation for research of application of new structural systems on the production of architecture, while identifying transformations that new geometries and their application techniques, will contribute to the development and divulgation of new spatial and typological solutions. That is the reason to claim a detailed analysis to advance on the design and construction of new architectures.

Sign in / Sign up

Export Citation Format

Share Document