skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


  • NSF Public Access
  • Search Results
  • Auxetic Composite Laminates with Through-Thickness Negative Poisson’s Ratio for Mitigating Low Velocity Impact Damage: A Numerical Study
Title: Auxetic Composite Laminates with Through-Thickness Negative Poisson’s Ratio for Mitigating Low Velocity Impact Damage: A Numerical Study
Auxetic materials are those that exhibit negative Poisson’s ratios. Such a unique property was shown to improve the indentation and impact resistances. Angle-ply composite laminates can be designed to produce negative Poisson’s ratio at the laminate level due to the large anisotropicity of the individual layer and the strain mismatch between adjacent layers. This paper investigates the effect of through-thickness negative Poisson’s ratio on the low velocity impact behaviors of carbon fiber reinforced polymer matrix composite laminates, including the global impact behaviors, as well as the delamination, and the fiber and matrix damage. Results from numerical investigations show consistently reduced fiber and matrix tensile damage in the auxetic laminate in all plies, in comparison to the non-auxetic counterpart laminates (up to 40% on average). However, the auxetic laminate does not present a clear advantage on mitigating the delamination damage or the matrix compressive damage.  more » « less
Award ID(s):
2202737
PAR ID:
10419979
Author(s) / Creator(s):
Date Published:
Journal Name:
Materials
Volume:
15
Issue:
19
ISSN:
1996-1944
Page Range / eLocation ID:
6963
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; (, Journal of Composite Materials)
    Introducing auxeticity or negative Poisson’s ratio is one potential solution to mitigate the low velocity impact damage of fiber reinforced polymer matrix composites, which can be achieved by tailoring the layup of an anisotropic composite laminate. This study aims to investigate the effect of laminate-level in-plane negative Poisson’s ratio on the low velocity impact behavior of carbon fiber reinforced polymer (CFRP) matrix composites using numerical simulations. The layups of the auxetic composites that allow them to produce negative Poisson’s ratios are identified based on the Classical Lamination Theory and verified through fundamental coupon-level experimental tests. To ensure meaningful comparisons, the non-auxetic counterpart composites are designed by allowing them to produce positive in-plane Poisson’s ratio while closely matching the longitudinal effective modulus of the auxetic laminate. The simulation results indicate that the auxetic laminates suffer smaller (12.6% on average) delamination area in top and bottom interfaces, much smaller (38% on average) matrix compressive damage in the top and bottom plies, and smaller (14.6% on average) fiber tensile damage area in each ply of the laminate at relatively higher impact energies (5 and 8 J). 
    more » « less
  2. ; ; (, Thin-Walled Structures)
    Composite laminates with negative Posson's ratios (i.e., auxetic composite laminates) were experimentally found to demonstrate a three-fold increase in buckling strength under uniaxial compression in comparison with the equivalent non-auxetic ones. To investigate whether the enhancement is genuinely due to the negative Poisson's ratio (i.e., the auxeticity) or merely caused by the concurrent change in the bending stiffness matrix as the composite layup changes, a novel monoclinic plate-based composite laminate approach is proposed, which for the first time, allows to isolate the auxeticity effect from the concurrent change of the stiffness matrix. Results provided theoretical proof that the auxeticity plays an active role in enhancing the critical buckling strength of layered composite structure. However, such a role is dynamically sensitive to elements in the bending stiffness matrix, especially the bending-twisting ratio and the anisotropy of the bending stiffness between the longitudinal and lateral directions. Insights are expected to provide guidance in exploiting negative Poisson's ratio for improving the stability of layered composite structures. 
    more » « less
  3. ; ; (, Destech Publications, Inc.)
    This research focused on testing the effect of the negative Poisson’s ratio of a carbon fiber composite on its critical buckling load. A secondary goal was to determine the accuracy of simulation compared to the experimental results for carbon fiber composites. In order to accomplish these two goals, both simulation and experimental testing were employed. For the simulation, ABAQUS software was used to determine predicted values for the critical buckling loads of auxetic and nonauxetic composites as well as the respective nonlinear force behavior of these composites. These results were then compared to experimental results of four auxetic and four non-auxetic specimens each experiencing uniaxial compressive tests. The results of simulation and experimentation showed that the critical buckling loads, and force sustained in general, of the auxetic composites were about three times higher than those of non-auxetic composites. While it appears that the negative Poisson’s ratio has a significant impact on the buckling strength of composite materials, further testing is required to determine the effects of other factors on the critical buckling loads. Along with this, the simulation was more accurate for the auxetic composites than for the non-auxetic composites. Therefore, further testing and simulation are required to determine the limits of simulation accuracy for composite structures. 
    more » « less
  4. ; (, 37th American Society for Composites (ASC) Technical Conference)
    Carbon fiber reinforced polymer (CFRP) matrix composites have become increasingly popular across industries such as aerospace and automotive industries due to its outstanding mechanical properties and significant weight saving capability. CFRP composites are also widely known to be highly tailorable. For instance, different laminate-level mechanical properties for CFRP composites can be achieved by varying the individual carbon fiber laminar arrangements, among one of them is the Poisson’s ratio. Conventional materials have a positive Poisson’s ratio (PPR), visualize any conventional materials in a 2D block shape, when stretching that material in longitudinal direction, contraction follows on the transverse direction, whereas for materials with a negative Poisson’s ratio (NPR), stretching in the longitudinal direction leads to expansion in the transverse direction. Materials with NPRs have been shown to improve the indentation and impact resistances, when compared to equivalent materials with PPRs. However, producing NPRs could potentially compromise other properties, such as tensile properties, which has not been reported. The current work investigates the effects of NPR on the tensile properties of CFRP composites. Specifically, a laminatelevel NPR of -0.4094 in the in-plane direction is achieved through ply arrangement of CFRP composites using classical lamination theory (CLT). The non-auxetic counterpart CFRP composites are designed to produce an PPR of 0.1598 in the in-plane direction while simultaneously match their elastic moduli in three directions with those of the auxetic composites. Results show that the predicted tensile modulus and in-plane Poisson’s ratio were in excellent agreement with the experiment results. It was found that the ultimate tensile strength and failure strain or ductility of auxetic specimens were on average 40% lower than those of the conventional CFRP composites. 
    more » « less
  5. ; ; (, AIAA SciTech 2020 Forum)
    Polymer matrix composites are popular in the aerospace industry due to their high strength to weight ratio. While they have become popular, understanding and predicting their specific damage evolution mechanisms remains a challenge especially in designing with damage tolerance criteria. One challenge often faced is the presence of surface damage either induced during manufacturing, machining, or service of a composite part. While many studies have investigated how quasi-static, low-velocity, and ballistic impact results in damage in the material, there remains a need to further understand the reduction in performance that results from such surface damage. In this work, micro-indentation was conducted on a unidirectional IM7/8552 laminate composite specimen to induce quasi-static impact damage that results in surface damage. The specimen was then loaded in tension to 33% of its expected failure load and imaged using synchrotron X-ray micro-computed tomography to qualitatively investigate the progression of surface damage into sub-surface damage. This work shows that at 33% of tensile failure load, surface damage propagates into delamination and fiber breakage of plies directly sub-surface. This work sheds light on the progression of surface damage at loads less than 50% of the ultimate strength of a unidirectional laminate composite. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email