Fracture properties of hybrid fibre-reinforced roller-compacted concrete in mode I with consideration of possible kinked crack

2018 ◽  
Vol 187 ◽  
pp. 248-256 ◽  
Author(s):  
H. Rooholamini ◽  
A. Hassani ◽  
M.R.M. Aliha
Keyword(s):  
Mode I ◽  
Fracture Properties ◽  
Roller Compacted Concrete ◽  
Kinked Crack ◽  
Hybrid Fibre

Fracture Behaviour of Modified Spruce Wood: A Study Using Linear and Non Linear Fracture Mechanics

Holzforschung ◽  
2002 ◽  
Vol 56 (2) ◽  
pp. 191-198 ◽  
Author(s):  
Alexander Reiterer ◽  
Gerhard Sinn
Keyword(s):  
Fracture Energy ◽  
Heat Treatments ◽  
Critical Stress Intensity Factor ◽  
Mode I ◽  
Mode Iii ◽  
Fracture Properties ◽  
Specific Fracture Energy ◽  
Wedge Splitting Test ◽  
Splitting Test ◽  
Specific Fracture

Summary The fracture properties of unmodified and modified (heat treatments under various conditions and acetylation) sprucewood are investigated using the wedge splitting test. Fracture parameters measured include critical stress intensity factor and specific fracture energy under Mode I loading and specific fracture energy under Mode III loading. The Mode I fracture properties are reduced by all kinds of modification. However, acetylation leads to a reduction of only 20%whereas heat treatments reduce the properties to a much greater extent, approximately 50%to 80%. The Mode III fracture properties are influenced less. SEM pictures of the fracture surfaces support the described findings.

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 Numerical Investigation of the Fracture Properties of Pre-Cracked Monocrystalline/Polycrystalline Graphene Sheets

Materials ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 263 ◽  
Author(s):  
Xinliang Li ◽  
Jiangang Guo
Keyword(s):  
Fracture Toughness ◽  
Grain Boundary ◽  
Misorientation Angle ◽  
Strain Energy ◽  
Unit Area ◽  
Crack Tip ◽  
Mode I ◽  
Fracture Properties ◽  
Mode I Fracture ◽  
Mode I Fracture Toughness

The fracture properties of pre-cracked monocrystalline/polycrystalline graphene were investigated via a finite element method based on molecular structure mechanics, and the mode I critical stress intensity factor (SIF) was calculated by the Griffith criterion in classical fracture mechanics. For monocrystalline graphene, the size effects of mode I fracture toughness and the influence of crack width on the mode I fracture toughness were investigated. Moreover, it was found that the ratio of crack length to graphene width has a significant influence on the mode I fracture toughness. For polycrystalline graphene, the strain energy per unit area at different positions was calculated, and the initial fracture site (near grain boundary) was deduced from the variation tendency of the strain energy per unit area. In addition, the effects of misorientation angle of the grain boundary (GB) and the distance between the crack tip and GB on mode I fracture toughness were also analyzed. It was found that the mode I fracture toughness increases with increasing misorientation angle. As the distance between the crack tip and GB increases, the mode I fracture toughness first decreases and then tends to stabilize.

Fracture Properties of Softwood under Mode I Loading Perpendicular to the Grain

2007 ◽  
Vol 340-341 ◽  
pp. 477-482
Author(s):  
Ming Bao Li ◽  
Jun Cao ◽  
Shi Qiang Zheng
Keyword(s):  
Stress Intensity Factor ◽  
Plastic Zone ◽  
Yield Criterion ◽  
Compact Tension ◽  
Tension Test ◽  
Mode I ◽  
Fracture Properties ◽  
Mode I Loading ◽  
Compact Tension Test ◽  
Shape And Size

Fracture properties of softwood under mode I loading perpendicular to the grain are studied in this paper. The stress intensity factor KIC in the R and L directions is measured by the compact tension test using small several specimens. The shape and size of plastic zone in crack tip is determined by numerical simulations based on von Hill yield criterion. The results show that anisotropic material constants do not affect the length of plastic zone along crack direction and it only operates on the plastic zone with θcr≠ 0. Strength ratios α1, α2 and toughness ratios r1, r2, influencing on the plastic zone, are discussed. Comparative analysis shows that r1 and r2 work markedly on the shape and size of plastic zone, whereas α1, α2 do less.

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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