Considering the Statistical Distribution of Dynamic Fracture Toughness Data and the Actual Loading Rate at Fracture Initiation When Applying ASTM E1921 at Elevated Loading Rates

2016 ◽  
Vol 5 (3) ◽  
pp. MPC20150050
Author(s):  
U. Mayer
Keyword(s):  
Fracture Toughness ◽  
Dynamic Fracture ◽  
Loading Rate ◽  
Fracture Initiation ◽  
Dynamic Fracture Toughness ◽  
Statistical Distribution ◽  
Loading Rates

Investigation of loading rate and plate thickness effects in dynamic fracture toughness of PMMA

1997 ◽  
Vol 57 (4) ◽  
pp. 459-460
Author(s):  
H. Wada ◽  
M. Seika ◽  
T.C. Kennedy ◽  
C.A. Calder ◽  
K. Murase
Keyword(s):  
Fracture Toughness ◽  
Dynamic Fracture ◽  
Loading Rate ◽  
Plate Thickness ◽  
Dynamic Fracture Toughness

Fracture Mechanics at Elevated Loading Rates in the Ductile to Brittle Transition Region

2017 ◽  
Author(s):  
Uwe Mayer ◽  
Thomas Reichert ◽  
Johannes Tlatlik
Keyword(s):  
Fracture Toughness ◽  
Dynamic Loading ◽  
Dynamic Fracture ◽  
Master Curve ◽  
Crack Arrest ◽  
Dynamic Fracture Toughness ◽  
Fracture Probability ◽  
High Rate ◽  
Loading Rates ◽  
Static Conditions

The rate-dependent reference temperature T0,x characterizes the fracture toughness of ferritic steels at the onset of cleavage. Fracture toughness values KJc,d were determined according to the Annex A1 of ASTM E1921 [1] which refers to the high rate annexes A14 and A17 of ASTM E1820 [2]. Results of extensive dynamic fracture toughness experiments at various loading rates, temperatures, specimen types and sizes revealed shortcomings in the transferability of the shape of the Master Curve under quasi-static conditions to elevated loading rates. In particular, the quasi-static Master Curve predicts lower fracture toughness values towards higher temperatures than experimentally observed under dynamic loading causing a steeper Master Curve shape. Fractographic examinations proved the relevance of local crack arrest under dynamic loading conditions, which is consistent with the view of the parallelism of dynamic fracture probability and probability of arrest.

Safety Assessment of Steels and Welds Under Cyclic and Monotonic Loadings at Low Temperatures

1984 ◽  
Vol 106 (4) ◽  
pp. 473-479
Author(s):  
N. Urabe ◽  
A. Yoshitake ◽  
H. Kagawa
Keyword(s):  
Fracture Toughness ◽  
Fatigue Life ◽  
Brittle Fracture ◽  
Low Temperatures ◽  
Safety Assessment ◽  
Loading Rate ◽  
Fracture Initiation ◽  
Fatigue Tests ◽  
Loading Rates ◽  
Wide Range

In order to investigate the mechanisms and the factors to govern the brittle fracture initiation during the fatigue crack propagation at low temperatures, fracture toughness tests under wide range of loading rates, fatigue tests at low temperatures and fracture toughness tests after having been given pre-loading were performed on steels and weld junctions. The fatigue fracture toughness Kfc was estimated as equivalent as the fracture toughness Kc under the monotonic tensile loading if they were compared at the same loading rate, since the residual stress due to the cyclic loading was less effective on the brittle fracture initiation. The calculated fatigue life based on Paris’s formula taken into consideration of the crack closure phenomena showed a good one-by-one agreement with the observed fatigue life up to the brittle fracture initiation. Therefore, a design curve was preliminarily drawn to determine the fatigue life at low temperatures.

IAEA Coordinated Research Project on Master Curve Approach to Monitor Fracture Toughness of RPV Steels: Effect of Loading Rate

2007 ◽  
Author(s):  
Hans-Werner Viehrig ◽  
Enrico Lucon
Keyword(s):  
Fracture Toughness ◽  
Master Curve ◽  
Loading Rate ◽  
Crack Arrest ◽  
Dynamic Fracture Toughness ◽  
Current Status ◽  
Research Project ◽  
Topic Area ◽  
Loading Rates ◽  
Data Assessment

In the final evaluation for the application of the Master Curve in the IAEA Coordinated Research Project Phase 5 (CRP-5), one of the areas which was identified as needing further work concerned the effects of loading rate on the reference temperature To up to impact loading conditions. This subject represents one of the three topic areas within the current CRP-8. The effect of loading rate can be broken down into two distinct aspects: 1) the effect of loading rate on the Master Curve To values for loading rates within the specified in ASTM E1921-05 for quasi-static loading (0.1–2 MPa√m/s); 2) the effect of loading rate on To values for higher loading rates, including impact conditions using instrumented precracked Charpy (PCC) specimens. The new CRP includes both aspects, but primarily focuses on the second element of loading rate effects, i.e. loading rates above 2 MPa√m/s. These issues are investigated within the topic area #2 of CRP-8 (Loading Rate Effect). The mandatory portion of this topic area required participation in a round-robin exercise (RRE) to validate the application of the Master Curve approach to PCC specimens tested in the ductile-to-brittle transition region using an instrumented pendulum (10 tests per participant on the JRQ material). The current status of the RRE is presented in [1]. The non-mandatory portion of this topic area consists in providing Master Curve data obtained at different loading rates on various RPV steels, in order to assess the loading rate dependence of To and compare it with an empirical model proposed by Wallin. Moreover, additional topics will be addressed, such as: • comparison of results from unloading compliance and monotonic loading in the quasi-static range; • estimation of fracture toughness from Charpy V-notch data; • assessment of crack arrest properties from instrumented Charpy results; • effect of irradiation on the relationship between static and dynamic fracture toughness.

Investigation of loading rate and plate thickness effects on dynamic fracture toughness of PMMA

1996 ◽  
Vol 54 (6) ◽  
pp. 805-811 ◽  
Author(s):  
H. Wada ◽  
M. Seika ◽  
T.C. Kennedy ◽  
C.A. Calder ◽  
K. Murase
Keyword(s):  
Fracture Toughness ◽  
Dynamic Fracture ◽  
Loading Rate ◽  
Plate Thickness ◽  
Dynamic Fracture Toughness

scholarly journals Rock Dynamic Fracture Characteristics Based on NSCB Impact Method

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Yanbing Wang
Keyword(s):  
Fracture Toughness ◽  
Dynamic Fracture ◽  
High Speed ◽  
Loading Rate ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Fracture Toughness ◽  
High Speed Photography ◽  
Rate Dependency ◽  
Hopkinson Pressure Bar ◽  
Rock Materials

In 2012, the International Society for Rock Mechanics (ISRM) recommended a new Notched Semicircular Bend (NSCB) method for the determination of dynamic fracture toughness of rock materials, but it did not consider the effect of some uncontrollable factors in the course of the experiment on the test result. This thesis firstly carried out dynamic fracture toughness experiments on several typical rock materials such as sandstone using the modified Split-Hopkinson Pressure Bar (SHPB) experimental system with high-speed photography, directly compared the dynamic fracture failure characteristics of several rock materials, and examined the loading rate dependency of the dynamic fracture toughness of rock materials. Based on the numerical analysis method of Discrete Lattice Spring Model (DLSM), it focused on the effect of bullet impact loading rate, loading area of incident bar, support restraints of clamping specimen, and other uncontrollable factors in the course of SHPB experiment on test results. The findings can be referenced for the improvement of NSCB method.

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