A numerical study of constraint effects on dynamic ductile crack initiation

Biswas, P.; Narasimhan, R.

doi:10.1016/s0167-6636(02)00154-0

Cited by 13 publications

(16 citation statements)

References 20 publications

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“…This occurs partially even when _ J is high. The above observation is contrary to isotropic plastic solids obeying von Mises yield criterion (Biswas and Narasimhan, 2002) where a similar TPB specimen was found to progressively lose constraint with increase in load level.…”

Section: Tablecontrasting

confidence: 68%

“…Indeed, negative Q can retard void nucleation and growth, thereby slowing down ductile fracture processes ahead of the tip. In this connection, it must be mentioned that Biswas and Narasimhan (2002) showed that for isotropic plastic solids, constraint loss under dynamic loading can cause an increase in the ductile fracture toughness. The results presented in this section for nearly rate independent material response imply that cleavage crack initiation which is expected to be controlled by the level of opening stress ahead of the tip (Ritchie et al, 1973) will also be impeded under dynamic loading.…”

Section: Angular Variation Of Stressmentioning

confidence: 99%

“…These studies showed that a specimen which maintains high constraint under quasi-static loading may exhibit progressive loss of triaxiality as the loading rate increases. Biswas and Narasimhan (2002) reported that this inertia-driven constraint loss may be responsible for the experimentally observed enhancement in dynamic fracture toughness of ductile materials (Owen et al, 1998). Jayadevan et al (2002b) found that strain rate sensitivity and material inertia have opposing effects on the stress distribution ahead of the tip.…”

Section: Introductionmentioning

confidence: 99%

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Effect of loading rate on crack tip fields in three point bend fracture specimen of FCC single crystal

Biswas

Narasimhan

2011

International Journal of Solids and Structures

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Keywords:Ductile FCC single crystal Crack tip fields Loading rate Three point bend specimen Finite element analysis a b s t r a c t In this work, the effect of impact loading on mode I stationary crack tip fields in a three point bend FCC single crystal fracture specimen is investigated using plane strain finite element analysis. The behavior of the single crystal is assumed to be elastic-perfectly plastic. The main objective is to examine the role of material inertia in influencing the stress levels as well as the pattern of slip and kink shear bands around the tip. The results show that under quasi-static loading high stress levels prevail ahead of the notch tip. However, the specimen suffers considerable loss of constraint under dynamic loading, particularly during the initial stages. This increases with loading rate _ J. Also significant spread of the plastic zone occurs in the forward sector ahead of the tip under impact loading which is akin to isotropic solids. The pattern of shear bands around the tip in the single crystal also changes with impact velocity. In rate dependent single crystals, a competition between rate sensitivity and material inertia is observed. Thus, while the former enhances the stresses near the tip, the latter tends to reduce them.

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Section: Tablecontrasting

confidence: 68%

Section: Angular Variation Of Stressmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of loading rate on crack tip fields in three point bend fracture specimen of FCC single crystal

Biswas

Narasimhan

2011

International Journal of Solids and Structures

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“…Detailed finite element calculations performed by Koppenhoefer and Dodds [73,74] clearly show that the increase of tearing resistance can be associated with a loss of constraint, or loss of triaxiality, that occurs at dynamic loading rates. Narasimhan and co-workers [75][76][77][78] also performed detailed numerical investigations on this issue. The elevated stresses at the crack tip generate high stresses in the remaining ligament leading to a greater plastic work elsewhere in the specimen.…”

Section: Data Analysis and Interpretationmentioning

confidence: 99%

Effect of irradiation-induced plastic flow localization on ductile crack resistance behavior of a 9%Cr tempered martensitic steel

Chaouadi

2008

Journal of Nuclear Materials

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“…While there are many studies on the constraint effect for fracture of stationary crack under quasi-static load, a few have been done for cracks under dynamic load (Koppenhoeffer and Dodds 1996;Jayadevan et al 2001;Biswas and Narasimhan 2002). In this paper, we studied the constraint effect on the fracture initiation of a stationary crack under dynamic loads.…”

Section: Introductionmentioning

confidence: 99%

Effect of loading rate on dynamic fracture initiation toughness of brittle materials

Kim

Chao

2007

Int J Fract

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Numerical simulation is carried out to investigate the effect of loading rate on dynamic fracture initiation toughness including the crack-tip constraint. Finite element analyses are performed for a single edge cracked plate whose crack surface is subjected to uniform pressure with various loading rate. The first three terms in the Williams' asymptotic series solution is utilized to characterize the crack-tip stress field under dynamic loads. The coefficient of the third term in Williams' solution, A 3 , was utilized as a crack tip constraint parameter. Numerical results demonstrate that (a) the dynamic crack tip opening stress field is well represented by the three term solution at various loading rate, (b) the loading rate can be reflected by the constraint, and (c) the constraint A 3 decreases with increasing loading rate. To predict the dynamic fracture initiation toughness, a failure criterion based on the attainment of a critical opening stress at a critical distance ahead of the crack tip is assumed. Using this failure criterion with the constraint parameter, A 3 , fracture initiation toughness is determined and in agreement with available experimental data for Homalite-100 material at various loading rate.

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A numerical study of constraint effects on dynamic ductile crack initiation

Cited by 13 publications

References 20 publications

Effect of loading rate on crack tip fields in three point bend fracture specimen of FCC single crystal

Effect of loading rate on crack tip fields in three point bend fracture specimen of FCC single crystal

Effect of irradiation-induced plastic flow localization on ductile crack resistance behavior of a 9%Cr tempered martensitic steel

Effect of loading rate on dynamic fracture initiation toughness of brittle materials

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