Narasimhan, R (1994) A numerical study of fracture initiation in a ductile material containing a dual population of second-phase particles-II. Dynamic loading. In: Engineering Fracture Mechanics, 47 (6). pp. 935-948.
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Some recent experimental studies with pre-notched bend specimens of 4340 steel under both static loading[A. T. Zehnder and A. J. Rosakis, J. appl. Mech. 57, 618-626 (1990)] and impact loading[A. T. Zehnder er al., Int. J. Fracture 42, 209-230 (199011 have shown that considerable crack-tunneling occurs in the interior of the specimens prior to gross fracture initiation on the free surfaces. The final fracture of the side ligaments happens because of shear-lip formation. The tunneled region is characterized by a flat fibrous fracture surface. In Part I of this work, the static experiments of A. T. Zehnder and A. J. Rosakis [J. appl. Mech. 57, 618-626 (199011 were analyzed using a 2D plane-strain finite-element procedure. The constitutive model that was employed in this analysis accounted for the ductile failure mechanisms of microvoid nucleation, growth and coalescence. The simulation also modeled void initiation at two populations of particles of different sizes. In this part, the same constitutive model as in Part I is used, along with a plane-strain transient finite-element procedure to analyze the impact experiments reported by A. T. Zehnder et al., [Int. J. Fracture 42, 209-230 (199011 corresponding to an impact speed of 5 m/set. A direct comparison is made between the static and dynamic results regarding the development of ductile failure in the ligament connecting the notch-tip and a simulated inclusion ahead of it. It is found that, to attain the same level of microvoid damage in this ligament, a larger value of J is required under dynamic loading. The strain rate and adiabatic temperature rise near the notch-tip are also examined.
|Item Type:||Journal Article|
|Additional Information:||The copyright of this article belongs to Elsevier.|
|Department/Centre:||Division of Mechanical Sciences > Mechanical Engineering|
|Date Deposited:||20 Nov 2006|
|Last Modified:||19 Sep 2010 04:30|
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