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  • Characterization of mixed-mode I/II fracture properties of

    Mode I: loading occurs the most often and produces the most damage. Because of this, it naturally receives the most attention in research, structural design, failure analysis, etc. It is commonly called the Opening Mode. Mode II: corresponds to shearing of the crack face due to in-plane shear stresses.

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  • STUDY OF THE FRACTURE BEHAVIOR OF FIBER REINFORCED

    with Mode II of fracture [1]. According to Ayatollahi et al. [2], pure shear loading is defined as a loading condition in which a specimen is subjected to equal and opposite parallel forces with negligible bending. Some researchers [3] do not accept the existence of mode II failure in concrete. It is due to the easy failure of concrete in mode I.

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  • Shear Loader and Performing Pure Mode II or Mixed …

    Feb 11, 2021 · Shear Loader and Performing Pure Mode II or Mixed Mode I and Mode II Shear Loading. Patent Number: 10,761,002. Abstract. A shear loader subjects a shear load on a sample and includes: a first shearer including: a first shearing face that provides a shearing plane; a first mating face; and a first knife edge; a second shearer including: a second

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  • FRACTURE MECHANICS FOR COMPOSITES - NASA

    using pure Mode I Double Cantilever Beam (DCB) (G II/G T=0), pure Mode II End Notched Flexure (ENF) (G II/G T=1), and Mixed Mode Bending (MMB) tests of varying ratios. A curve fit of these data is performed to determine a mathematical relationship between G c and G II/G T. Failure is expected when, for a given mixed mode ratio G II /G

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  • (PDF) Evaluation of mixed mode I_II fracture toughness …

    pure mode I tests, although adaptations of the techniques to pure mode II have also been developed (Wang and Williams 1992 ; Blackman et al. 2003, 2005, 2006 ). One goal of this study was to test mixed-mode conditions, but each specimen was partially tested at …

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  • An Incremental Cohesive Law for Delamination Under a Mixed

    Nov 12, 2020 · where K I, K II and K m are the stiffness used in the cohesive law for pure mode I, mode II and mixed-mode with a mode mixity of B, respectively (see details of the cohesive law definition in the next section).With this modified formulation of the cohesive constitutive law, the dependence of the macro-scale response on the inter-laminar strength can be eliminated but only during the

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  • On the orientation and patterns of wing cracks and

    France. The faults appear to accommodate pure mode II displacement discontinuity. In the dilational quadrants, wing cracks and veins (gray) form. In the compressional quadrants, solution surfaces (dotted lines) form. (b) Wing cracks near tip of a fracture that experienced mixed …

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  • Effect of mode mixity, temperature, binder content, and

    Load induced fracture of asphalt concrete in pavement systems rarely occur in pure mode I. Mixed mode (I/II) loading condition can be considered as the predominant loading state of the HMA layers, and considerable research has been conducted on the single parameter characterization of mixed mode fracture of asphalt concrete in the past decade, .

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  • Design of loading devices for mixed-mode fatigue crack

    In this thesis, a loading device suitable for mixed-mode I and II fatigue crack propagation tests of a compact tension shear (CTS) specimen has been designed and constructed. Computations of fatigue crack propagation life and maximum applied load to a CTS specimen in order to follow linear elastic fracture mechanics was performed.

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  • Characterization of mixed mode crack opening in concrete

    Jun 24, 2011 · In real concrete structures cracks often open in mixed mode after their initiation. To capture the direct material behavior of a mixed mode crack opening a stiff biaxial testing machine, capable of imposing both normal and shear loads on a given crack area, has been applied. The opening and sliding components of the mixed mode displacement are measured using a custom made …

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  • A suitable mixed mode I/II test specimen for fracture

    2 days ago · However by reducing S 1 value, the curve of mode I goes downward and the curve of mode II geometry factor moves upward such that at a specific S 1 distance (e.g. S 1 = 2.5 mm or S 1 /R = 0.078 for a/H = 0.4) mode I curve stands on zero axis but mode II curve has a non-zero magnitude, in which this situation corresponds to pure mode II loading

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  • Numerical Simulation of Mixed-Mode Fatigue Crack Growth

    Apr 23, 2020 · This work concentrates on the fracture behaviour of the compact tension specimen under mixed-mode loading, and numerical investigation using ANSYS Mechanical APDL 19.2 finite element program with different modes of mix angles is carried out. The prediction of mixed-mode fatigue life under constant amplitude fatigue loading for the compact tension shear specimen (CTS) is employed …

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  • UiS Brage: Design of loading devices for mixed-mode

    In this thesis, a loading device suitable for mixed-mode I and II fatigue crack propagation tests of a compact tension shear (CTS) specimen has been designed and constructed. Computations of fatigue crack propagation life and maximum applied load to a CTS specimen in order to follow linear elastic fracture mechanics was performed.

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  • Study of mixed mode fracture toughness and fracture

    In this paper, centrally straight-notched Brazilian disc (CSNBD) specimens were used to determine the pure mode I, pure mode II and combined mode fracture strength (or fracture toughness) of gypsum . The centre crack with required inclination angle was introduced by …

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  • Sudden Fracture from U-Notches in Fine-Grained Isostatic

    Mar 26, 2013 · The U-notched maximum tangential stress (UMTS) criterion, proposed originally and utilized previously by the author and his co-researcher for predicting mixed mode I/II fracture in plexi-glass (PMMA) and also pure mode II fracture in PMMA and soda-lime glass, was employed to estimate the experimental results reported in literature dealing with brittle fracture of many U-notched fine …

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  • Study on translaminar fracture toughness under mixed mode

    Abstract Mixed-mode translaminar fracture toughness behaviour is experimentally investigated using glass/epoxy composite laminate with (0/45)° orientation. Experimental investigation is conducted using Compact Tension Shear (CTS) mixed mode (I/II) fracture specimens having a/W = 0.5. The specimen plates of thickness 4.5 mm were carefully fabricated using hand lay-up technique.

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  • Shear fracture (Mode II) of brittle rock | Request PDF

    Nov 03, 2017 · Abstract. This study investigates the rate and path of fatigue crack growth under mixed mode I/II loading in the presence of tensile and compressive stresses. Compact tension shear (CTS) specimens made of 42CrMo4 steel are subjected to pure mode I, …

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  • Cohesive mixed mode fracture modelling and …

    Apr 01, 1997 · The present tests and numerical results, using double-edge notched specimen, generate during the en- tire load history pure mode-II conditions. Due to the inhomogeneity of concrete, after mode-II crack initia- tion, its further propagation is arrested and overidden by more critical diagonal shear failure in compression.

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  • Investigation by Digital Image Correlation of Mixed-Mode I

    Feb 26, 2021 · In particular, when the bottom supports are located symmetrically to the crack line (i.e., when S 1 = S 2) and the crack line is parallel to the load (i.e., when α = 0°), the specimen is subjected to pure opening mode I. With different combinations of S 2 /R and α, mixed-mode I/II can be obtained.

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  • Patents | NIST

    Shear Loader and Performing Pure Mode II or Mixed Mode I and Mode II Shear Loading. NIST Inventors. Edward Pompa, and . Patent Description The device is a shearing system that is essentially a portion of a large scissors, used to precisely shear a specimen while recording the loads and deformations. It consists of two metallic half­ devices

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