Effect of ply thickness on fracture of notched composite laminates

Vaidya, Rajesh S.; Klug, J. C.; Sun, C. T.

doi:10.2514/3.13781

Cited by 4 publications

(5 citation statements)

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“…As the strength is dependent on the actual damage preceding final failure, various methods based on damage parameters have been proposed to predict the notched strength of virgin and fatigue‐damaged laminates 13 –15 . These methods incorporate the presence of subcritical damage by directly modelling the physical mechanisms occurring around the hole; they therefore require a precise characterization of these mechanisms and a clear comprehension of their role in the failure and the overall response of the composite material.…”

Section: Introductionmentioning

confidence: 99%

Response of notched carbon/PEEK and carbon/epoxy laminates subjected to tension fatigue loading

Aymerich

Found

2000

Fatigue Fract Eng Mat Struct

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In this study a comparison is made between the tensile static and fatigue behaviours of quasi‐isotropic carbon/PEEK and carbon/epoxy notched laminates, selected as separate representatives of both tough and brittle matrix composites. Damage progression was monitored by various non‐destructive (ultrasonic scanning and x‐radiography) and destructive (deply and microscopic examinations) techniques, and by continuously measuring the change in stiffness, in order to identify the effect of damage on mechanical properties. The experimental observations indicated that fatigue damage in carbon/epoxy laminates consists of a combination of matrix cracks, longitudinal splitting and delaminations which attenuate the stress concentration and suppress fibre fracture at the notch; as a consequence, fatigue failure can be reached only after very high numbers of cycles while tensile residual strengths continuously increase over the range of lives investigated (103–106 cycles). Due to the superior matrix toughness and the high fibre‐matrix adhesion, the nature of fatigue damage in carbon/PEEK laminates strongly depends on the stress level. At high stresses the absence of early splitting and delaminations promotes the propagation of fibre fracture therefore resulting in poor fatigue performances and significant strength reductions; while at low stress levels damage modes are matrix controlled and this again translates into very long fatigue lives. These results indicate a strong influence of the major damage mechanisms typical of the two material systems on the behaviour of the laminates, with the nature, more than the amount, of damage appearing as the controlling parameter of the material response up to failure.

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Section: Introductionmentioning

confidence: 99%

Response of notched carbon/PEEK and carbon/epoxy laminates subjected to tension fatigue loading

Aymerich

Found

2000

Fatigue Fract Eng Mat Struct

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“…Prediction of the notched strength of FRP composite has been a problem due to its inherent complexity and the number of factors involved in designing. In the past few decades, extensive research has been performed on the fracture behavior of FRP composite containing notch 38,40,45–47 . Initially, linear elastic fracture mechanics (LEFM) was applied by some researchers for the prediction of notch strength of FRP composite containing stress raiser 48–50 .…”

Section: Assessment Of Mechanical Performance Of Composite Component ...mentioning

confidence: 99%

“…39 few decades, extensive research has been performed on the fracture behavior of FRP composite containing notch. 38,40,[45][46][47] Initially, linear elastic fracture mechanics (LEFM) was applied by some researchers for the prediction of notch strength of FRP composite containing stress raiser. [48][49][50] However, the LEFM model applied by these researchers is valid for limited cases and bypasses the micro and macro failures associated with crack propagation.…”

Section: Assessment Of Mechanical Performance Of Composite Component ...mentioning

confidence: 99%

An overview of mechanical properties and failure mechanism of FRP laminates with hole/cutout

Gupta

Pal

Ray

2023

J of Applied Polymer Sci

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Aerospace and aircraft companies follow a pyramidal structure of testing, ranging from specimen tests to full-scale structure tests, for aircraft structural design. At the base level, open hole strength evaluation is one of the qualification procedures for composite components. The holes are made in the structural components to accommodate bolts and rivets in order to assemble the parts into a single unit. Holes in the component are also used to fulfill functional requirements, such as the passage of wire bundles. FRP components are sensitive to these holes/cutouts as substantial decrement in the strength is observed in several experiments. The degradation in the strength of the component is due to stress concentration around the hole. This review aims to comprehend the effect of the hole on the mechanical properties of FRP laminates; the emphasis is mainly on CFRP laminates and experimental results. An overview of tensile, compressive, flexural and post buckling properties of laminates with the hole is presented to aid in the optimal design of the component. Finally, the failure mechanism during loading is discussed and described through a graphical presentation.

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“…Numerous research endeavors have delved into examining the strength and failure patterns in laminated composites under open-hole tension conditions. These investigations encompass aspects such as fiber orientations, stacking order, ply thickness, and machining methods, all of which impact the composite's mechanical properties [39][40][41][42]. Previous research into notched laminates has primarily concentrated on attributes related to the notches, encompassing aspects such as their quantity, hole profile, and dimensions.…”

Section: Introductionmentioning

confidence: 99%

Effect of Hole Size on Open Hole Tensile (OHT) and Flexural Strength (OHF) of Aramid-Basalt Fibre Reinforced Polymer Composites

Fernandes,

Dutta,

Pai

et al. 2023

Preprint

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The open hole tensile and flexural test of composites holds immense importance in aerospace and structural engineering. These tests provide critical insights into how composites perform under real-world conditions, allowing for the development of materials that meet rigorous standards, thereby ensuring the safety and durability of aircraft and other applications. This study investigates the influence of hole size on the open hole tensile (OHT) and flexural properties (OHF) of plane woven aramid/epoxy (AFRP), basalt/epoxy (BFRP), and aramid-basalt/epoxy (ABFRP) sandwiched laminates. Specimens with three different hole sizes viz., 4 mm, 6 mm, 8 mm were prepared and tested according to ASTM D5766 and ASTM D7264 for OHT and OHF performance respectively. Results indicated that the hybridization of aramid-basalt layers in a sandwich lay up significantly improved the mechanical performance when compared to only aramid laminate. However, with the increase in hole size the mechanical properties declined irrespective of the material. Basalt fibres showed higher hole sensitivity under tensile loading due to its brittle fracture mechanism while aramid fibres exhibited higher hole sensitivity under flexural loading which can be attributed to its the poor compressive strength. The effect of hole size on the damage mechanism has also been highlighted through scanning electron microscope (SEM). Major failure modes observed are delamination around the hole edges, ductile and brittle fibre fractures, and delamination.

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Effect of ply thickness on fracture of notched composite laminates

Cited by 4 publications

References 0 publications

Response of notched carbon/PEEK and carbon/epoxy laminates subjected to tension fatigue loading

Response of notched carbon/PEEK and carbon/epoxy laminates subjected to tension fatigue loading

An overview of mechanical properties and failure mechanism of FRP laminates with hole/cutout

Effect of Hole Size on Open Hole Tensile (OHT) and Flexural Strength (OHF) of Aramid-Basalt Fibre Reinforced Polymer Composites

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