Application of split Hopkinson tension bar technique to the study of dynamic fracture properties of materials

Abstract

A novel approach is proposed in determining dynamic fracture toughness (DFT) of high strength steel, using the split Hopkinson tension bar (SHTB) apparatus, combined with a hybrid experimental-numerical method. The center-cracked tension specimen is connected between the bars with a specially designed fixture device. The fracture initiation time is measured by the strain gage method, and dynamic stress intensity factors (DSIF) are obtained with the aid of 3D finite element analysis (FEA). In this approach, the dimensions of the specimen are not restricted by the connection strength or the stress-state equilibrium conditions, and hence plane strain state can be attained conveniently at the crack tip. Through comparison between the obtained results and those in open publication, it is concluded that the experimental data are valid, and the method proposed here is reliable. The validity of the obtained DFT is checked with the ASTM criteria, and fracture surfaces are examined at the end of paper.

Experimental Determination of the Dynamic Initiation Fracture Toughness of Composite Modified Double base Propellant

“…Without proper pulse shaping, it is difficult to achieve dynamic stress equilibrium in such materials because the specimen may fail immediately from its end in contact with incident bar when it is impacted by the incident bar. What's more, the rigid-impact-contact caused by the bar/striker will bring about high frequency bit noise in the dynamic tests [6,7]. In this experiment, we found that a combined disc shaped pulse shaper made from soft materials (copper and rubber) can be utilized to minimize the high frequency bit noise to obtain ideal results.…”

Experimentation and Modeling of the Tension Behavior of Polycarbonate at High Strain Rates

“…The air gun system is used to propel the striker tube. A detailed illustration of the working principle of the air gun system can be found in [22].…”

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

“…Displacements, velocities and rupture time measured by detection sensors attached to a SHPB were compared with 2D numerical simulations. (Xu et al, 2012) proposed a novel approach to determine dynamic fracture toughness of high strength steel 40Cr using the SHTB technique and an hybrid experimental-numerical method. For such a purpose, curves of dynamic stress intensity factor history were obtained by full-scale 3D finite element simulation and dynamic fracture toughness was determined according to the fracture-initiation time measured by strain gauge method.…”

“…Representative examples of this particular methodology can be found in (Anderson and Rosakis, 2005;Joudon et al, 2014;Kalthoff, 1985;Rubio-González et al, 2008;Shuter, 2002;Xu et al, 2012;Yokoyama, 1993) Purely optical methods are also very extended since, in general, they are inertia free. The shadow optical method of caustics (Kalthoff, 1986;Manogg, 1964) was the first successful optical method.…”