scholarly journals A Wedge-DCB Test Methodology to Characterise High Rate Mode-I Interlaminar Fracture Properties of Fibre Composites

2018 ◽  
Vol 183 ◽  
pp. 02052 ◽  
Author(s):  
Sathiskumar A. Ponnusami ◽  
Hao Cui ◽  
Borja Erice ◽  
Mehtab V. Pathan ◽  
Nik Petrinic
Keyword(s):  
Crack Opening ◽  
High Rate ◽  
Experimental Methodology ◽  
Dynamic Mode ◽  
Mode I ◽  
Fiber Reinforced ◽  
Fracture Properties ◽  
Interlaminar Fracture ◽  
Cohesive Zone Modelling ◽  
High Level

A combined numerical-experimental methodology is presented to measure dynamic Mode-I fracture properties of fiber reinforced composites. A modified wedge-DCB test using a Split-Hopkinson Bar technique along with cohesive zone modelling is utilised for this purpose. Three different comparison metrics, namely, strain-displacement response, crack propagation history and crack opening history are employed in order to extract unique values for the cohesive fracture properties of the delaminating interface. More importantly, the complexity of dealing with the frictional effects between the wedge and the DCB specimen is effectively circumvented by utilising right acquisition techniques combined with an inverse numerical modelling procedure. The proposed methodology is applied to extract the high rate interlaminar fracture properties of carbon fiber reinforced epoxy composites and it is further shown that a high level of confidence in the calibrated data can be established by adopting the proposed methodology.

Mode-I and mode-II interlaminar fracture properties of high modulus pitch-based carbon fiber reinforced polymers containing different nanostructures

2021 ◽  
pp. 002199832110492
Author(s):  
Kimiyoshi Naito ◽  
Chiemi Nagai
Keyword(s):  
Carbon Fiber ◽  
Fiber Reinforced Polymers ◽  
Mode I ◽  
Mode Ii ◽  
High Modulus ◽  
Carbon Fiber Reinforced Polymers ◽  
Reinforced Polymers ◽  
Sic Nanoparticles ◽  
Fracture Properties ◽  
Interlaminar Fracture

The mode-I and mode-II interlaminar fracture properties of high modulus pitch-based carbon fiber reinforced polymers (CFRPs) (fiber: K13C; resin: EX-1515 cyanate ester) modified with 20–30 nm β-SiC nanoparticles or multiwalled-carbon nanotubes (MWCNTs) were investigated. Different volume fractions of both the β-SiC nanoparticles (1, 2, 5, and 10 vol%) and MWCNTs (1, 3, 5, and 7 vol%) were tested. The values of the mode-I and mode-II interlaminar fracture toughness of the CFRPs containing the lowest volume fractions of these nanostructures were larger compared with the unfilled composite but decreased with increasing the volume fraction of the inclusions. No differences in mechanical properties were observed among the different nanostructure types.

scholarly journals Woven Glass Fiber Composites with Aligned Carbon Nanotube Sheet Interlayers

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Hardik Bhanushali ◽  
Philip D. Bradford
Keyword(s):  
Fracture Toughness ◽  
Glass Fiber ◽  
Mode I ◽  
Mode Ii ◽  
Interlaminar Fracture Toughness ◽  
Fiber Reinforced ◽  
Interlaminar Fracture ◽  
Glass Fiber Reinforced ◽  
Short Beam ◽  
Woven Glass Fiber

This investigation describes the design, fabrication, and testing of woven glass fiber reinforced epoxy matrix laminates with aligned CNT sheets integrated between plies in order to improve the matrix dominated through thickness properties such as the interlaminar fracture toughness at ply interfaces. Using aligned CNT sheets allows for a concentration of millimeter long CNTs at the most likely point of laminate failure. Mode I and Mode II interlaminar fracture toughness of various CNT modified samples were investigated using double cantilever beam (DCB) and end notched flexure (ENF) experiments, respectively. Short beam strength (SBS) and in-plane tensile properties of the CNT modified samples were also investigated. Moderate improvement was observed in Mode I and Mode II fracture toughness at crack initiation when aligned CNT sheets with a basis weight of 0.354 g/m2were used to modify the ply interface. No compromise in the in-plane mechanical properties of the laminate was observed and very little improvement was observed in the shear related short beam strength of the CNT modified laminates as compared to the control samples. Integration of aligned CNT sheets into the composite laminate imparted in-plane and through thickness electrical properties into the nonconductive glass fiber reinforced epoxy composite laminates.

Characterization of Interlaminar Fracture Properties of Advanced Polymer Matrix Composites Interleaved With Buckypaper

2016 ◽  
Author(s):  
Masoud Yekani Fard ◽  
John M. Woodward ◽  
Siddhant Datta ◽  
Brian Raji ◽  
Aditi Chattopadhyay
Keyword(s):  
High Speed ◽  
Polymer Matrix Composites ◽  
Beam Theory ◽  
High Yield ◽  
Mode I ◽  
Design Guideline ◽  
Fracture Properties ◽  
Interlaminar Fracture ◽  
Manufacturing Method ◽  
Calibration Methods

Recently a novel high-speed/high-yield surfactant-free manufacturing method has been developed for manufacturing of large size buckypaper. In spite of this development, there is no data on the effects of microstructural characteristics on the structural properties of surfactant-free buckypaper based nanocomposites. This investigation examines the effects of the proposed manufacturing procedure on the resultant interlaminar fracture properties of buckypaper based nanocomposites. Buckypaper samples were fabricated using the novel surfactant-free technique. Buckypaper based nanocomposite samples were subjected to mode I, II, and I-II fracture testing in Double Cantilever Beam (DCB ), End Notched Flexure (ENF) and 4-point End Notched Flexure (4ENF), and Mixed Mode Bending (MMB) configurations, respectively. Analysis of the test specimens in terms of mode I energy release rates showed good agreement among Modified Beam Theory, Compliance Calibration, and Modified Compliance Calibration methods. ENF and 4ENF tests gave very consistent crack initiation and propagation results for mode II fracture. The fracture envelope function of the composite and the nanocomposites was developed as a design guideline for nanocomposite materials.

scholarly journals Determining effective interface fracture properties of 3D fiber reinforced foam core sandwich structures

2018 ◽  
Vol 37 (7) ◽  
pp. 490-503 ◽  
Author(s):  
Zachary T Kier ◽  
Anthony M Waas
Keyword(s):  
Cantilever Beam ◽  
Sandwich Structure ◽  
Double Cantilever Beam ◽  
Sandwich Structures ◽  
Interface Fracture ◽  
Mode I ◽  
Foam Core ◽  
Fiber Reinforced ◽  
Fracture Test ◽  
Fracture Properties

Foam core sandwich composites are finding a wider use in aerospace, automotive, and construction applications. These structures present unique challenges in terms of material failure and interaction and are sensitive to damage and imperfections introduced during manufacturing. An emerging class of 3D fiber reinforced foam core aims to replace monolithic foams used in sandwich structure cores particularly in demanding high-performance aerospace applications. This research is focused on investigating the development of testing methods capable of measuring the effective interface fracture properties between the facesheet and the core in 3D fiber reinforced foam cores. Double cantilever beam and end-notched flexure specimens are developed to evaluate the mode I and mode II fracture properties of a 3D fiber reinforced foam core. The design, development, and initial failure of a mode I interface fracture test for 3D fiber reinforced foam cores are presented. The digital image correlation results on the failed tests allowed for a different approach to be utilized in designing a new bonded double cantilever beam specimen for testing the mode I fracture of a 3D fiber reinforced foam core sandwich structure that resulted in a successful interface fracture test. The bonded DCB specimens exhibited relatively smooth crack propagation and produced GIc values similar to honeycomb sandwich structures and significantly higher than comparable foam structures.

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