A mixed mode fracture specimen for mode II dominant deformation

Banks‐Sills, Leslie; Arcan, M.; Bortman, Jacob

doi:10.1016/0013-7944(84)90122-x

Cited by 79 publications

(28 citation statements)

References 20 publications

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“…3. For example, Banks-sills et al (1984) who studied the mode II crack behavior using an Arcan-type specimen presented a set of isochromatic fringes which are not symmetric and continuous (see Fig. 5a).…”

Section: Discussionmentioning

confidence: 99%

T-Stress Effects on Isochromatic Fringe Patterns in Mode II

Ayatollahi

Zakeri

2007

Int J Fract

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The theory of photoelasticity is used to study analytically the effects of T-stress on the fringe patterns around the crack tip in mode II crack specimens. The locus of an isochromatic fringe determined by taking into account the T-stress is compared with the locus of a fringe with no T-stress. It is shown for mode II cracks that in the presence of T-stress, the fringe loops are neither symmetric nor continuous. Asymmetric and discontinuous fringe patterns predicted in this paper are consistent with the experimental results observed previously in photoelasticity tests.

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Section: Discussionmentioning

confidence: 99%

T-Stress Effects on Isochromatic Fringe Patterns in Mode II

Ayatollahi

Zakeri

2007

Int J Fract

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“…This confusion can partly be attributed to the lack of standard procedures for the determination of mode II or mode III fracture toughness. The specimen designs proposed to date permit the evaluation of only pure mode II [11][12][13][14][15] or pure mode III [16,17] which makes the comparison of fracture toughness data under different modes of loading extremely difficult. In a recent publication Richard and Kuna [18] have proposed an 'All Fracture Mode (AFM)' specimen and loading fixture wherein it is possible to conduct fracture toughness tests for pure mode I, pure mode II, pure mode III and for all possible combinations of the above-mentioned using the same specimen design and loading fixture.…”

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confidence: 99%

Comparison of fracture toughness of a 7XXX aluminum alloy under mode I, mode II and mode III loading

Kamat

Prasad

1993

Int J Fract

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A crack in a body can be subjected to three distinct modes of loading: mode I (tensile), mode II (in-plane shear) or mode III (anti-plane shear). In most practical situations, structures are subjected to complex loading and can have flaws or cracks oriented in arbitrary directions. Hence, it is essential to evaluate the fracture toughness of engineering materials under different loading modes to correctly assess their damage tolerance. However, most of the published literature is concerned with only mode I fracture toughness and very limited experimental data are available on the fracture toughness under mode II or mode III loading [1][2][3][4][5][6][7][8][9][10]. The studies have yielded contradictory results with no clear picture emerging on whether mode II and mode III fracture toughnesses are higher or lower than mode I fracture toughness. This confusion can partly be attributed to the lack of standard procedures for the determination of mode II or mode III fracture toughness. The specimen designs proposed to date permit the evaluation of only pure mode II [11][12][13][14][15] or pure mode III [16,17] which makes the comparison of fracture toughness data under different modes of loading extremely difficult. In a recent publication Richard and Kuna [18] have proposed an 'All Fracture Mode (AFM)' specimen and loading fixture wherein it is possible to conduct fracture toughness tests for pure mode I, pure mode II, pure mode III and for all possible combinations of the above-mentioned using the same specimen design and loading fixture. This testing procedure should minimize the errors associated with using different specimen geometries for the evaluation of fracture toughness under different loading modes.The objective of this study was to evaluate the fracture toughness of an experimental 7XXX alloy under mode I, mode II and mode III loading using the AFM specimen so as to determine the lowest fracture toughness of this alloy and to assess the feasibility of using the AFM specimen proposed by Richard and Kuna [ 18].The experimental 7XXX aluminum alloy was of the nominal composition: 5.2 Zn, 2.2 Mg, 0.067 Mn, balance A1. The alloy was received in the as forged, natural aged condition. The tensile properties of the alloy were as follows: yield strength (~y) = 230MPa, ultimate tensile strength (~) = 360MPa, uniform plastic strain (e o)-= 16 percent. Mode I, mode II and moore III tests were conducted using the AFM specimen, illustrated in Fig. 1, with w = 30mm, a = 15mm, c = 22.5mm and t = 13.5mm. The loading device which was used is shown in Fig. 2. The device consists of two force introduction elements (1) and (2) which are Int Journ of Fracture 63 (1993)R8 diametrically connected to one another by the specimen (3), forming an octantal sphere. The load was applied by means of an Instron 8500 servohydraulic machine through connecting rods linked to the force introduction elements by threaded holes. The appropriate mode of loading was chosen by correctly selecting the diametrically opposite holes. The detailed pr...

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“…Test methods for fracture characterisation of the pure modes I and II have been well established [5,6]. However, while a number of options exist for mixed mode I/II testing [7,8,9], it is an area of considerable contentiousness and uncertainty, in particular regarding the mode decomposition of asymmetric specimens.…”

Section: Introductionmentioning

confidence: 99%