Impact Response of Fiber Composite Structures

1991 ◽  
Vol 44 (11S) ◽  
pp. S256-S263 ◽  
Author(s):  
Stephen R. Swanson
Keyword(s):  
Program Analysis ◽  
Impact Loading ◽  
Composite Structures ◽  
Analytical Study ◽  
Fiber Composite ◽  
Structural Response ◽  
Composite Plates ◽  
Surface Strain ◽  
Transverse Impact ◽  
Good Agreement

The problem of impact loading of fiber composite structures is important because of the possibility of accidental damage occuring during service. The present paper is a review of a combined experimental and analytical study of transverse impact loading of carbon/epoxy composite plates and cylinders. Scaling of response with structure size was investigated as part of the program. Analysis procedures for dynamic response were developed, using Ritz techniques for plates and Fourier series expansions combined with Laplace transforms for the cylinders. The experimental results showed good correlation with scaling rules developed for structural response. Good agreement was also obtained between experiment and analysis for surface strain response in both the plates and the cylinders. Scaling of damage is seen to be more complicated, with measured delamination sizes exhibiting a dependence on absolute specimen size as would be predicted by fracture mechanics.

RESIDUAL PLASTIC STRAIN STATE AND DELAMINATION PATTERN OF COMPOSITE LAMINATES WITH AUTOMATED INDUCED-GAP SUBJECTED TO HEMI-SPHERICAL IMPACT LOADING

2021 ◽  
Author(s):  
MOHAMMADHOSSEIN GHAYOUR ◽  
MEHDI HOJJATI ◽  
RAJAMOHAN GANESAN
Keyword(s):  
Plastic Strain ◽  
Impact Loading ◽  
Residual Strain ◽  
Composite Structures ◽  
Strain State ◽  
Composite Plates ◽  
Structural Level ◽  
Manufacturing Defects ◽  
Initiation And Propagation ◽  
The Impact

Automated manufacturing defects are types of composite structure defects that occur during fiber deposition by advanced robots. The induced gap is the most probable type of defect in the Automated Fiber Placement (AFP) technique. This defect can affect the mechanical performance of the composite structures at both material level by inducing the material inhomogeneity and the structural level by introducing the consolidation effect in the structure during the curing process. The current study investigates the effect of induced-gaps on the damage assessment of thin composite plates under Low-Velocity Impact (LVI) loading. The paper focuses on the delamination initiation and propagation and the residual plastic strain state of the impacted plates. The primary application of this study is to understand the interaction of induced gaps on the delamination pattern of composite samples subjected to LVI. For this purpose, a series of LVI tests are performed. Ultrasonic C-scan analysis and microscopic observation are implied to evaluate the internal damage due to impact loading. Finite Element (FE) analyses are then performed to evaluate the residual strain of the composite plates under Impact Energy (IE) loading less than 15 J. Then, the residual plastic strain in the impact zone is evaluated using a meso-macro method, and the effect of the local plasticity that occurs in the gap zones on the delamination initiation and propagation is studied. Results show that the stress relaxation due to the resin plasticity at the gap areas can affect the delamination pattern of the impacted composite plates. It is also shown that the residual strain of the impacted plates at the gap areas are new sources of the damages that need to be considered in the LVI analysis of the composite plates manufactured by the AFP technique.

scholarly journals Guided Waves for Damage Detection in Complex Composite Structures: The Influence of Omega Stringer and Different Reference Damage Size

2020 ◽  
Vol 10 (9) ◽  
pp. 3068
Author(s):  
Jochen Moll ◽  
Christian Kexel ◽  
Jens Kathol ◽  
Claus-Peter Fritzen ◽  
Maria Moix-Bonet ◽  
...  
Keyword(s):  
Composite Structures ◽  
Guided Waves ◽  
Fiber Composite ◽  
Composite Plates ◽  
Guided Wave ◽  
Probability Of Detection ◽  
Carbon Fiber Composite ◽  
Technical Validation ◽  
Pod Analysis ◽  
The Impact

The third dataset dedicated to the Open Guided Waves platform aims at carbon fiber composite plates with an additional omega stringer at constant temperature conditions. The two structures used in this work are representative for real aircraft components. Comprehensive measurements were recorded in order to study (I) the impact of the omega stringer on guided wave propagation, and (II) elliptical reference damages of different sizes located at three separate positions on the structure. Measurements were recorded for narrowband excitation (5-cycle toneburst with varying carrier frequencies) and broadband excitation (using chirp waveforms). The paper presents the results of a technical validation including numerical modelling, and enables further research, for example related to probability of detection (POD) analysis.

scholarly journals Analytical Study of a Pin-Loaded Hole in Unidirectional Laminated Composites With Triangular and Circular Fibers

2013 ◽  
Vol 80 (2) ◽  
Author(s):  
Hossein Robati ◽  
Mohammad Mahdi Attar
Keyword(s):  
Composite Structures ◽  
Analytical Study ◽  
Glass Fibers ◽  
Stress Fields ◽  
Shear Lag ◽  
Stress Concentrations ◽  
Equilibrium Equations ◽  
Shear Lag Model ◽  
Lag Model ◽  
Good Agreement

The problem of stress concentrations in the vicinity of pin-loaded holes is of particular importance in the design of multilayered composite structures made of triangular or circular glass fibers. It is assumed that all of the fibers in the laminate lie in one direction while loaded by a force p0 at infinity, parallel to the direction of the fibers. According to the shear lag model, equilibrium equations are derived for both types of fibers. A rectangular arrangement is postulated in either case. Upon the proper use of boundary and bondness conditions, stress fields are derived within the laminate, along with the surrounding pinhole. The analytical results are compared to those of the finite element values. A very good agreement is observed between the two methods. According to the results, composite structures made of triangular glass fibers result in lower values of stress concentrations around the pin, as opposed to those of circular glass fibers.

scholarly journals Introduction to Macroscopic Optimal Design in the Mechanics of Composite Materials and Structures

2021 ◽  
Vol 5 (2) ◽  
pp. 36
Author(s):  
Aleksander Muc
Keyword(s):  
Composite Materials ◽  
Composite Structures ◽  
Constitutive Relations ◽  
A Priori ◽  
Chemical Properties ◽  
Composite Plates ◽  
Failure Criteria ◽  
Lagrange Equations ◽  
Homogenization Methods ◽  
Mechanics Of Composite Materials

The main goal of building composite materials and structures is to provide appropriate a priori controlled physico-chemical properties. For this purpose, a strengthening is introduced that can bear loads higher than those borne by isotropic materials, improve creep resistance, etc. Composite materials can be designed in a different fashion to meet specific properties requirements.Nevertheless, it is necessary to be careful about the orientation, placement and sizes of different types of reinforcement. These issues should be solved by optimization, which, however, requires the construction of appropriate models. In the present paper we intend to discuss formulations of kinematic and constitutive relations and the possible application of homogenization methods. Then, 2D relations for multilayered composite plates and cylindrical shells are derived with the use of the Euler–Lagrange equations, through the application of the symbolic package Mathematica. The introduced form of the First-Ply-Failure criteria demonstrates the non-uniqueness in solutions and complications in searching for the global macroscopic optimal solutions. The information presented to readers is enriched by adding selected review papers, surveys and monographs in the area of composite structures.

Modeling of fiber composite structures for the calculation of the structural intensity

2021 ◽  
Vol 262 ◽  
pp. 113631
Author(s):  
Pasquale Junior Capasso ◽  
Giuseppe Petrone ◽  
Nikolai Kleinfeller ◽  
Sergio De Rosa ◽  
Christian Adams
Keyword(s):  
Composite Structures ◽  
Fiber Composite ◽  
Structural Intensity

Development of a hybrid element to model intralaminar damage in thick composite plates under impact loading

2021 ◽  
pp. 109024
Author(s):  
L. Manseri ◽  
P. Navarro ◽  
O. Dorival ◽  
S. Marguet ◽  
B. Mahmoud ◽  
...  
Keyword(s):  
Impact Loading ◽  
Composite Plates ◽  
Hybrid Element

The effect of nanoparticle additive on surface milling in glass fiber reinforced composite structures

2021 ◽  
pp. 096739112110141
Author(s):  
Ferhat Ceritbinmez ◽  
Ahmet Yapici ◽  
Erdoğan Kanca
Keyword(s):  
Composite Materials ◽  
Glass Fiber ◽  
Composite Structures ◽  
Fiber Composite ◽  
Cutting Speed ◽  
Fiber Reinforced ◽  
Fiber Reinforced Composite ◽  
Reinforced Composite ◽  
Glass Fiber Reinforced ◽  
Composite Layers

In this study, the effect of adding nanosize additive to glass fiber reinforced composite plates on mechanical properties and surface milling was investigated. In the light of the investigations, with the addition of MWCNTs additive in the composite production, the strength of the material has been changed and the more durable composite materials have been obtained. Slots were opened with different cutting speed and feed rate parameters to the composite layers. Surface roughness of the composite layers and slot size were examined and also abrasions of cutting tools used in cutting process were determined. It was observed that the addition of nanoparticles to the laminated glass fiber composite materials played an effective role in the strength of the material and caused cutting tool wear.

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