On Testing of Charpy Specimens Using the One-point Bend Impact Technique

Dynamic Fracture Initiation Toughness of a Gamma (Met-PX) Titanium Aluminide at Elevated Temperatures

“…This is probably because the crack initiation times for the high impact velocity experiments are relatively short; this makes it difficult to identify the frame in which crack initiation occurred because of the discrete nature of the high-speed camera record. A similar discrepancy in the crack initiation times from the peak load identified from the strain gage records and high-speed camera records in high impact velocity fracture experiments have also previously been reported by Kalthoff et al [42] while using a drop-weight machine and by Rittel et al [30] using the MSHPB. They attributed this disagreement in crack initiation times to the material inertia effects under the high impact velocity loading.…”

“…In their work, based on the arrival of the transmitted waves, they concluded that the specimen lost contact with the support for a very short period of time. Weisbrod and Rittel [29] and Rittel et al [30] used the MSHPB in a onepoint-bend impact configuration, to determine the fracture toughness of specimens with a relatively small size. More recently, the MSHPB technique has been successfully used by Irfan et al [31][32][33] to study the dynamic fracture of discontinuously reinforced aluminum composites; by Popelar et al [34] in the dynamic fracture toughness of 4340 steel; by Martins et al [35] and Martins and Prakash [36] in the dynamic fracture of linear medium-density polyethylene; by Jiang and Vecchio [37] in the study of the dynamic fracture of lightweight metals and steels; and by Evora and Shukla [38] in the characterization of polyester/TiO 2 nanocomposites.…”

Determination of the dynamic stress intensity factor of a specimen under one-point bending from the measurement of the load-point displacement

“…The impac tin g mass may be the strike r of a Ch arpy pendulum or a mass proj ected by a pneumatic device. Whe n the fracture pro perties of a materi al must be o btained at hi gh strain rate, the one-point be nding test may be perfo rmed using ex pe rime ntal devices based o n modificati o ns of the Hopkinson bar [3][4][5]. These syste ms con sist of a bar of a give n le ngth and di ameter (striker bar) whi ch is put in contact with the central section of a c racked specime n ide ntical to that whi ch would be used in a three-po int be nding test.…”

“…To obtain K 1 (t) in o ne-point be nding tests, the Fini te E le ment method may be used [3][4][5][6][7], but other simplified methods have bee n used . These me thods are based o n the modal analys is of a cracked beam subjected to a kn own load in its central secti o n. With thi s procedure, the di splace me nt of any section JOURNAL DE PHYSIQUE IV of the beam can be calculated.…”

Dynamic fracture of high-strength metallic alloys: experiments and modelling

“…Such an idea was based on the linearity of the fracture process, that meant, LEFM assumptions. The validity of such procedure was assessed in (Rittel and Weisbrod, 2001) where it was applied to characterise the dynamic fracture toughnes of a commercial tungsten base heavy alloy, and in (Rittel et al, 2002) where it was applied for the assessment of the dynamic fracture energy of notched Charpy A508 steel specimens. In (Rittel and Rosakis, 2005), the results of dynamic fractureinitiation toughness of a bulk metallic glass system and a composite obtained by the one-point impact technique were compared with the ones obtained by coheren gradient sensing interferometry (CGS).…”