Scope for Vibration Based Nondestructive Estimation of the Residual Buckling Strength of Damaged Composite Laminates

Buckling and Postbuckling Analyses of a Skew Plate

Journal of Mechanics ◽

10.1017/s1727719100002471 ◽

2008 ◽

Vol 24 (4) ◽

pp. 347-355 ◽

Cited By ~ 1

Author(s):

H. W. Liao ◽

H. Y. Huang

Keyword(s):

Composite Laminates ◽

High Order ◽

Design Parameters ◽

Aerospace Structures ◽

Critical Buckling Load ◽

Buckling Strength ◽

Skew Plate ◽

Post Buckling ◽

Polynomial Expansions ◽

Important Design

AbstractThe applications of skew plates in the construction of aerospace structures are well known. The critical buckling load and post-buckling strength are two important design parameters of skew composite laminates. In this study, the refined buckling and nonlinear postbuckling solutions of a homogenous isotropic skew plate based on polynomial expansions of various degrees have been examined. Numerical results based on high-order Rayleigh-Ritz solutions are presented for certain type of oblique plates.

Download Full-text

Delamination Buckling of Kevlar and Twaron Stitched Glass\Epoxy Composite Laminates by Experiments

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.136.109 ◽

2008 ◽

Vol 136 ◽

pp. 109-114

Author(s):

Madusudhanan R. Parlapalli ◽

Kwok C. Soh ◽

Dong Wei Shu

Keyword(s):

Composite Laminates ◽

Epoxy Composite ◽

Flexural Modulus ◽

Vertical Displacement ◽

Buckling Loads ◽

Buckling Strength ◽

Different Types ◽

Delamination Buckling ◽

Membrane Strain ◽

Delamination Length

In the present paper, effects of through-the-thickness stitching of delaminated glass/epoxy composite laminates with two different types of aramid threads, Kevlar® and Twaron® threads, on the buckling loads are studied. The buckling loads are predicted based on the Southwell, Vertical displacement and Membrane strain plot methods from the experimental data. Flexural modulus of the stitched and unstitched glass/epoxy composite laminates, knot tensile strength of Kevlar® and Twaron® stitching threads are obtained experimentally. From the Southwell, Vertical displacement and Membrane strain plot methods it is observed that stitching either by Kevlar® or Twaron® threads is effective in improving the buckling strength of glass/epoxy composite laminates when the delamination length is greater than 0.5L, L is the length of the laminate.

Download Full-text

Hygro-Thermally Curvature-Stable Free-Layer Composite Laminates with Extension-Twist Coupling

Advanced Composites Letters ◽

10.1177/096369351802700303 ◽

2018 ◽

Vol 27 (3) ◽

pp. 096369351802700 ◽

Cited By ~ 1

Author(s):

D Cui ◽

D K Li ◽

S M Zhou

Keyword(s):

Tensile Strength ◽

Compressive Strength ◽

Composite Laminates ◽

Differential Evolution Algorithm ◽

Free Layer ◽

Strong Constraint ◽

Buckling Strength ◽

Coupled Effect ◽

Layer Composite ◽

Improved Differential Evolution Algorithm

The tensile strength and compressive strength are indispensable indexes during the design process of composite laminates. For hygro-thermally curvature-stable extension-twist coupled laminates, the improved Differential Evolution Algorithm combined with penalty function is adopted to solve the nonlinear strong constraint of free-layer laminates. The synchronous optimization of multiple targets is achieved, which includes extension-twist coupled effect, tensile strength, compressive strength and buckling strength. Results are presented for free-layer graphite/epoxy composites laminates that consist of 1–18 plies. Finally the hygro-thermal effect, extension-twist coupled effect and buckling strength are simulated and verified.

Download Full-text

Numerical Study on Buckling Resistance of Uniaxially Compressed Laminates Containing V-Shaped Edge Notch

Advanced Engineering Forum ◽

10.4028/www.scientific.net/aef.41.27 ◽

2021 ◽

Vol 41 ◽

pp. 27-41

Author(s):

Nikhil Aditya ◽

Jyoti Vimal

Keyword(s):

Composite Laminates ◽

Numerical Study ◽

Weight Ratio ◽

Considerable Effect ◽

Notch Radius ◽

Notch Angle ◽

Buckling Strength ◽

End Conditions ◽

Edge Notch ◽

The Impact

The purpose of this study is to investigate the impact of a V-shaped cutout on the buckling strength of E-glass epoxy composite laminates. In aircraft components, cutouts are more often used for inspection, ventilation, access to critical areas, fitting a particular component, and increasing the strength to weight ratio of the structure. In this paper, symmetric and antisymmetric laminates of E-Glass/Epoxy unidirectional are used and the effect of notch parameters such as notch radius(r), depth of the notch(h), and notch angle(α) is observed under monoaxial compression. Effects of end conditions and plate aspect ratio(l/b) are analyzed. It is observed that the notch radius does not have a considerable effect on buckling strength but the notch angle after 90⁰ shows a good dip in buckling loads as compared to 30⁰,45⁰, and 60⁰. Depth of notch and end conditions creates a considerable loss in buckling strength. As the h/b ratio is increased, the drop in buckling strength becomes significant. Clamped -pinned end condition of the plate gives a lower value of load multiplier as compared to clamped -clamped. As we increase the l/b ratio of the plate, buckling of the plate becomes easier. The position of the notch (a) also affects buckling strength which is maximum for a/l=0.25 and minimum for a/l=0.5.

Download Full-text