Self-healing sandwich composite structures

2012 ◽  
Author(s):  
D. Fugon ◽  
C. Chen ◽  
K. Peters
Keyword(s):  
Composite Structures ◽  
Sandwich Composite ◽  
Self Healing

Self Healing of Epoxy Composite for Aircraft's Structural Applications

2008 ◽  
Vol 136 ◽  
pp. 39-44 ◽  
Author(s):  
Willy C.K. Tan ◽  
J.C. Kiew ◽  
K.Y. Siow ◽  
Z.R. Sim ◽  
H.S. Poh ◽  
...  
Keyword(s):  
Composite Structures ◽  
Polymeric Materials ◽  
Hollow Fibre ◽  
The Body ◽  
Strength Increase ◽  
Self Healing ◽  
Structural Applications ◽  
Self Repair ◽  
Repair Systems ◽  
Point Bend

When one cut himself, it's amazing to watch how quickly the body acts to mend the wound. Immediately, the body works to pull the skin around the cut back together. The concept of repair by bleeding of enclosed functional agents serves as the biomimetric inspiration of synthetic self repair systems. Such synthetic self repair systems are based on advancement in polymeric materials; the process of human thrombosis is the inspiration for the application of self healing fibres within the composite materials. Preliminary results based on flexural 3 point bend test on prepared samples have shown the healed hollow fibre laminate has a healed strength increase of 47.6% compared to the damaged baseline laminate. These results gave us confidence that there is a great potential to adopt such self healing mechanism on actual composite parts like in aircraft’s composite structures.

ONR REVIEW: ARCHITECTED COMPOSITES FOR DAMAGE TOLERANCE IN EXTREME CONDITIONS

2021 ◽  
Author(s):  
PAVANA PRABHAKAR ◽  
VINAY DAMODARAN, ◽  
ABARINATHAN PUSHPARAJ SUBRAMANIYAN
Keyword(s):  
Energy Dissipation ◽  
Composite Structures ◽  
Computational Models ◽  
Peak Load ◽  
Moisture Diffusion ◽  
Honeycomb Structure ◽  
Sandwich Composite ◽  
Extreme Conditions ◽  
Improved Performance ◽  
Damage Tolerant

The long-term goal of this ONR funded project is to facilitate the design of architected composites that play a key role in damage tolerant and resilient structures. The main emphasis is on developing new composite structures with improved performance and durability as compared to conventional structural composites. To that end, we will present our work in detail on the following within the realm of sandwich composites along with a novel Machine Learning framework for stress prediction in composites: 1) Novel recoverable sandwich composite structures: Traditional sandwich cores such as foam core or honeycomb structures are good options for enabling lightweight and stiff structures. Although, these cores are known to dissipate energy under extreme conditions such as impact loading, they experience permanent damage. Here, our goal is to design core structures that undergo substantial deformation without accumulating damage and recover their original geometric configuration after the loading is removed. In contrast to a traditional foam or honeycomb structure, we have developed a multi-layer architected core design that facilitates significant deformation beyond the initial peak load, yielding a larger energy dissipation during impact and other extreme loading scenarios. We utilize the concept of pseudo-bistability of truncated cone unit cells to achieve elastic buckling for energy dissipation and shape recovery of core structures. 2) Tailoring of sandwich composite facings: Our objective is to establish the influence of fiber architecture on moisture diffusion pathways in FRPC facings for enabling damage tolerant facing designs. To that end, we have evaluated the moisture kinetics in FRPCs by developing micromechanics based computational models within FEM. We have explained the effect of tortuous diffusion pathways that manifest within FRPCs due to internal fiber architectures. Finally, we established the relationship between tortuosity and diffusivity that can be used for studying moisture diffusion in other FRPCs.

Multi-Objective Optimal Design of Sandwich Composite Laminates Using Simulated Annealing and FEM

2008 ◽  
Author(s):  
A. Sarhadi ◽  
M. Tahani ◽  
F. Kolahan ◽  
M. Sarhadi
Keyword(s):  
Simulated Annealing ◽  
Optimal Design ◽  
Composite Laminates ◽  
Composite Structures ◽  
Simulated Annealing Algorithm ◽  
Core Layer ◽  
Sandwich Composite ◽  
Surface Layers ◽  
Multi Objective ◽  
Aspect Ratios

Multi-objective optimal design of sandwich composite laminates consisting of high stiffness and expensive surface layers and low-stiffness and inexpensive core layer is addressed in this paper. The object is to determine ply angles and number of surface layers and core thickness in such way that natural frequency is maximized with minimal material cost and weight. A simulated annealing algorithm with finite element method is used for simultaneous cost and weight minimization and frequency maximization. The proposed procedure is applied to Graphite-Epoxy/Glass-Epoxy and Graphite-epoxy/Aluminum sandwich laminates and results are obtained for various boundary conditions and aspect ratios. Results show that this technique is useful in designing of effective, competitive and light composite structures.

Some Results and Issues in the Non-Destructive Evaluation of Sandwich Composite Structures

2001 ◽  
Author(s):  
Emmanuel O. Ayorinde ◽  
Ronald F. Gibson ◽  
Feizhong Deng
Keyword(s):  
Composite Structures ◽  
Failure Modes ◽  
Sandwich Beam ◽  
Sandwich Composite ◽  
Glass Composite ◽  
Transverse Loading ◽  
Three Point Bending ◽  
Damage States ◽  
Vibration Modal ◽  
Non Destructive

Abstract This paper focuses on the use of basic NDE methods like ultrasonics, imaging and vibration testing to assess the integrity of some sandwich composites which have been subjected to transverse loading. Samples of a foam core, glass composite facing sandwich beam of varying thicknesses and end notch lengths were tested in three point bending and assessed by these NDE methods. The results show that core shear and indentation failures appear to be the prominent failure modes for these geometries and materials, and that changes in the damping and vibration modal frequencies of the beams can indicate damage states.

Flexural resistance and deformation behaviour of CFRP-ULCC-steel sandwich composite structures

2021 ◽  
Vol 257 ◽  
pp. 113080
Author(s):  
Zhenyu Huang ◽  
Yingwu Zhou ◽  
Guantao Hu ◽  
Weixiong Deng ◽  
Heng Gao ◽  
...  
Keyword(s):  
Composite Structures ◽  
Deformation Behaviour ◽  
Sandwich Composite ◽  
Flexural Resistance

scholarly journals Comparative Study of Sound Transmission Losses of Sandwich Composite Double Panel Walls

2020 ◽  
Vol 10 (4) ◽  
pp. 1543 ◽  
Author(s):  
Chukwuemeke William Isaac ◽  
Marek Pawelczyk ◽  
Stanislaw Wrona
Keyword(s):  
Composite Structures ◽  
Transmission Loss ◽  
Optimization Problems ◽  
Sound Transmission ◽  
Industrial Applications ◽  
Sandwich Composite ◽  
Acoustic Response ◽  
Transmission Losses ◽  
Emission Index ◽  
Selection Of

The increasing motivation behind the recently wide industrial applications of sandwich and composite double panel structures stems from their ability to absorb sounds more effectively. Meticulous selection of the geometrical and material constituents of both the core and panels of these structures can produce highly desirable properties. A good understanding of their vibro-acoustic response and emission index such as the sound transmission loss (STL) is, therefore, a requisite to producing optimal design. In this study, an overview of recent advances in STL of sandwich and composites double panels is presented. At first, some salient explanation of the various frequency and controlled regions are given. It then critically examines a number of parameter effects on the STL of sandwich and composite structures. Literatures on the numerical, analytical and experimental solutions of STL are systematically presented. Efficient and more reliable optimization problems that maximize the STL and minimize the objective functions capable of degrading the effectiveness of the structure to absorb sounds are also provided.

A probabilistic approach for design and certification of self-healing advanced composite structures

2011 ◽  
Vol 225 (4) ◽  
pp. 435-449 ◽  
Author(s):  
H R Williams ◽  
R S Trask ◽  
I P Bond
Keyword(s):  
Composite Structures ◽  
High Performance ◽  
Probabilistic Approach ◽  
Healing Time ◽  
Self Healing ◽  
Structural Failure ◽  
Healing System ◽  
Order Of Magnitude ◽  
Damage Tolerant

Design and certification of novel self-healing aerospace structures was explored by reviewing the suitability of conventional deterministic certification approaches. A sandwich structure with a vascular network self-healing system was used as a case study. A novel probabilistic approach using a Monte Carlo method to generate an overall probability of structural failure yields notable new insights into design of self-healing systems, including a drive for a faster healing time of less than two flight hours. In the case study considered, a mature self-healing system could be expected to reduce the probability of structural failure (compared to a conventional damage-tolerant construction) by almost an order of magnitude. In a risk-based framework this could be traded against simplified maintenance activity (to save cost) and/or increased allowable stress (to allow a lighter structure). The first estimate of the increase in design allowable stresses permitted by a self-healing system is around 8 per cent, with a self-healing system much lighter than previously envisaged. It is thought these methods and conclusions could have wider application to self-healing and conventional high-performance composite structures.

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