Modal Approach for Processing One‐ and Three‐point Bend Test Data for Dsif–time Diagram Determination. Part Ii—calculations and Results

Rokach, IV

doi:10.1046/j.1460-2695.1998.00088.x

Cited by 12 publications

(13 citation statements)

References 12 publications

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“…In the case of a notched beam with a short time to fracture subjected to one-point bending tests, the latter authors established that the beam model is not relevant. The response of the specimen was therefore modelled using finite element methods [22], [23], where the eigenmodes were determined using a 2-D model for the beam [24]. The maintenance of contact and loss of contact at the supporting points has also been studied experimentally in [25].…”

Section: Introductionmentioning

confidence: 99%

A non-equilibrium approach to processing Hopkinson Bar bending test data: Application to quasi-brittle materials

Delvare

Hanus

Bailly

2010

International Journal of Impact Engineering

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International audienceThe aim of this paper was to describe a method of analysing the test data recorded during a Hopkinson Bar bending test. This three-point dynamic bending test was designed for testing the strength of materials under dynamic loads. It is carried out on a specimen consisting of a beam placed on two supports, which is subjected to an impact. The use of Hopkinson Bar as supports makes it possible to determine the forces and displacements at these points. An analytical solution for the transient response of a long beam subjected to a transverse impact was used to determine the impact force and the displacement. This procedure applies for the first few instants when the motions generated by the impact have not yet reached the supports, and the mechanical state of the specimen is identical to that of an unsupported beam. It is suitable for use with quasi-brittle materials for which failure occurs at the very beginning of the test. The material strength is determined at the time of failure, which is characterised by a sudden decrease in the bending moment. The results of a test in which a quasi-brittle material was loaded up to failure are presented and analysed as outlined above. The results obtained confirm the relevance of the present method

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Section: Introductionmentioning

confidence: 99%

A non-equilibrium approach to processing Hopkinson Bar bending test data: Application to quasi-brittle materials

Delvare

Hanus

Bailly

2010

International Journal of Impact Engineering

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“…The static calibration of the near-field strain gauge enabled the additional force measurement directly by the 01028-p.3 as calculated according to Rokach [16][17][18]. Material: 42CrMo4.…”

Section: Force Equlibrium and Crack Initiationmentioning

confidence: 99%

“…During force equilibrium, F 1 and F 2 can be used to calculate K stat I and U p . Due to possible bending vibrations of the specimen, the dynamic stress intensity factor K dyn I was calculated according to Rokach [16][17][18]. The calculation of K dyn I (t) involves both the force in the incident bar and in the transmission bar.…”

Section: Calculation Of the J Integralmentioning

confidence: 99%

Crack initiation at high loading rates applying the four-point bending split Hopkinson pressure bar technique

Henschel

Krüger

2015

EPJ Web of Conferences

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Abstract. Dynamic crack initiation with crack-tip loading rates ofK ≈ 2 · 10 6 MPa √ ms −1 in a high strength G42CrMoS4 steel was investigated. To this end, a previously developed split Hopkinson pressure bar with four-point bending was utilised. Vnotched and pre-cracked Charpy specimens were tested. The detection of dynamic crack initiation was performed by analysing the dynamic force equilibrium between the incident and the transmission bar. Additionally, the signal of a near-field strain gauge and high-speed photography were used to determine the instant of crack initiation. To account for vibrations of the sample, a dynamic analysis of the stress intensity factor was performed. The dynamic and static analyses of the tests produced nearly the same results when a force equilibrium was achieved. Fracture-surface analysis revealed that elongated MnS inclusions strongly affected both the dynamic crack initiation and growth. Blunting of the precrack did not take place when a group of MnS inclusions was located directly at the precrack tip. Due to the direction of the elongated MnS inclusions perpendicular to the direction of crack growth, the crack could be deflected. The comparison with a 42CrMo4 steel without elongated MnS inclusions revealed the detrimental effect in terms of resistance to crack initiation. Taking the loading-rate dependency into consideration, it was shown that there was no pronounced embrittlement due to the high loading rates.

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“…The function w Ã b ðaÞ with which the SIF is calculated from the applied load (see Section 3), was compared to the values of w Ã b ðaÞ obtained from the results presented by Rokach [17] for OPB specimens, and from those calculated by Guinea et al [20] for TPB specimens. • the proposed expression,…”

Section: Sif From the Measurement Of The Applied Loadmentioning

confidence: 99%

“…Rokach [17] gives empirical formulae for the parameters K s I , g i and x i by fitting the results of 2D numerical analysis of different values of crack length and span-to-width ratio.…”

Section: Introductionmentioning

confidence: 99%

General expressions for the stress intensity factor of a one-point bend beam

Villa

Loya

Fernández-Sáez

2007

Engineering Fracture Mechanics

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The aim of this work is to find general expressions to determine the stress intensity factor of a one point bend beam like specimen, whether from the measurement of the applied load or the crack mouth opening displacement. The expressions, obtained by applying the superposition principle, involve the decomposition of the general case into three auxiliary problems. The solution of two of them (pure bending and three point bending) is well known, while the solution of the third (one point bending) is developed in the present work. The proposed expressions are compared to numerical results obtained by the finite element method and their accuracy is equal to or better than available expressions published elsewhere.

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Modal Approach for Processing One‐ and Three‐point Bend Test Data for Dsif–time Diagram Determination. Part Ii—calculations and Results

Cited by 12 publications

References 12 publications

A non-equilibrium approach to processing Hopkinson Bar bending test data: Application to quasi-brittle materials

A non-equilibrium approach to processing Hopkinson Bar bending test data: Application to quasi-brittle materials

Crack initiation at high loading rates applying the four-point bending split Hopkinson pressure bar technique

General expressions for the stress intensity factor of a one-point bend beam

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