Journal ArticleDOI
Dynamic fracture initiation and propagation in 4340 steel under impact loading
Alan T. Zehnder,Ares J. Rosakis +1 more
Reads0
Chats0
TLDR
In this article, the authors used the optical method of reflected caustics combined with high speed photography to investigate the dynamic fracture initiation and propagation in 4340 steel. And they found that the crack tip velocity and stress intensity factor time records varied smoothly and repeatably allowing for a straightforward interpretation of the data.Abstract:
Dynamic fracture initiation and propagation in 4340 steel was investigated experimentally using the optical method of reflected caustics combined with high speed photography. A new crack propagation testing configuration consisting of a three point bend specimen loaded in a drop weight tower was used. It was found that prior to crack initiation the stress intensity factor time record calculated using the dynamic tup load and a static formula disagrees with the actual stress intensity factor measured by caustics. During crack propagation, the crack tip velocity and stress intensity factor time records varied smoothly and repeatably allowing for a straightforward interpretation of the data. The experiments show that for the particular heat treatment of 4340 steel used, the dynamic fracture propagation toughness depends on crack tip velocity through a relation that is a material property.read more
Citations
More filters
Journal ArticleDOI
Finite-deformation irreversible cohesive elements for three-dimensional crack-propagation analysis
Michael Ortiz,Anna Pandolfi +1 more
TL;DR: In this paper, a three-dimensional finite deformation cohesive element and a class of irreversible cohesive laws are proposed to track dynamic growing cracks in a drop-weight dynamic fracture test.
Journal ArticleDOI
Review of experimental techniques for high rate deformation and shock studies
TL;DR: In this paper, a variety of techniques used to obtain the mechanical properties of materials at high rates of strain (⩾10 s−1) are summarised, including dropweight machines, split Hopkinson pressure bars, Taylor impact and shock loading by plate impact.
Journal ArticleDOI
Hopkinson Bar Loaded Fracture Experimental Technique: A Critical Review of Dynamic Fracture Toughness Tests
TL;DR: In this paper, the authors present a review of various aspects of Hopkinson bar fracture testing, including the analysis of advantages and disadvantages of loading systems and sample configurations, a discussion of operating principles for determining dynamic load and sample displacement in different loading configurations, and a comparison of various fracture parameters (load, displacement, fracture time, and fracture toughness) such as theoretical formula, optical gauges, and strain gauges.
Journal ArticleDOI
Configurational forces and the basic laws for crack propagation
TL;DR: In this article, the authors developed a framework for dynamical fracture, concentrating on the derivation of basic field equations that describe the motion of the crack tip in two space-dimensions.
Journal ArticleDOI
Three Dimensional Cohesive-Element Analysis and Experiments of Dynamic Fracture in C300 Steel
TL;DR: In this article, coherent gradient sensing (CGS) has been used to study dynamic fracture in C300 maraging steel, where the specimens were subjected to three-point bend impact loading under a drop weight tower and high speed photographs of the CGS interferograms were analyzed to determine the crack tip location, the velocity and the dynamic fracture toughness as a function of time.
References
More filters
Journal ArticleDOI
An experimental investigation into dynamic fracture: I. Crack initiation and arrest
TL;DR: In this paper, the authors examined crack initiation and arrest in thin sheets of Homalite-100 and showed that cracks can propagate rapidly with constant velocity even though the stress intensity factor varies considerably during this propagation.
Journal ArticleDOI
On crack-tip stress state: An experimental evaluation of three-dimensional effects
TL;DR: In this article, the authors investigated the extent of the crack-tip stress field using reflected and transmitted caustics and found that plane-stress conditions prevail at distances from the crack tip greater than half the specimen thickness, while no significant plane-strain region is detected.
Journal ArticleDOI
On the uniqueness of plane elastodynamic solutions for running cracks
L.B. Freund,R. J. Clifton +1 more
TL;DR: In this article, it was shown that the near tip stress field for running cracks has universal spatial dependence in a coordinate system local to the crack tip, and the rate at which energy is absorbed by the running crack can then be calculated in terms of the crack motion and the scalar stress intensity factors.
Journal ArticleDOI
The determination of dynamic fracture toughness of AISI 4340 steel by the shadow spot method
TL;DR: In this article, the dynamic crack propagation experiments have been performed using wedge loaded double cantilever beam specimens of an austenitized, quenched and tempered 4340 steel.
Book ChapterDOI
Experimental determination of dynamic stress intensity factors by shadow patterns
J. Beinert,J. F. Kalthoff +1 more
TL;DR: In this paper, the shadow pattern method was used to measure stress intensity factors in static and dynamic fracture mechanics problems, which yields high accuracy of measurement, but is still simple to apply.