Study on the cause of brittle fracture during earthquakes in steel bridge bentfocusing on stress triaxiality

2010 ◽  
pp. 679-679
Author(s):  
H Tamura ◽  
E Sasaki ◽  
H Yamada ◽  
H Katsuchi
Keyword(s):  
Brittle Fracture ◽  
Stress Triaxiality ◽  
Steel Bridge

Involvements of stress triaxiality in the brittle fracture during earthquakes in steel bridge bents

2009 ◽  
Vol 9 (3) ◽  
pp. 241-252 ◽  
Author(s):  
Hiroshi Tamura ◽  
Eiichi Sasaki ◽  
Hitoshi Yamada ◽  
Hiroshi Katsuchi ◽  
Theeraphong Chanpheng
Keyword(s):  
Brittle Fracture ◽  
Stress Triaxiality ◽  
Steel Bridge ◽  
Bridge Bents

scholarly journals ANALYTICAL STUDY FOCUSING ON STRESS TRIAXIALITY ON FACTOR OF BRITTLE FRACTURE DURING EARTHQAKES IN STEEL BRIDGE BENTS

2010 ◽  
Vol 66 (3) ◽  
pp. 420-434
Author(s):  
Hiroshi TAMURA ◽  
Eiichi SASAKI ◽  
Hitoshi YAMADA ◽  
Hiroshi KATSUCHI
Keyword(s):  
Brittle Fracture ◽  
Analytical Study ◽  
Stress Triaxiality ◽  
Steel Bridge ◽  
Bridge Bents

scholarly journals Micromechanical Modeling of Brittle Fracture of French RPV Steel: A Comprehensive Study of Stress Triaxiality Effect

2008 ◽  
Author(s):  
Jean-Philippe Mathieu ◽  
Olivier Diard ◽  
Karim Inal ◽  
Sophie Berveiller
Keyword(s):  
Brittle Fracture ◽  
Low Temperatures ◽  
Mean Field ◽  
Three Dimensional ◽  
Stress Triaxiality ◽  
Micromechanical Modeling ◽  
Multiscale Approach ◽  
Local Approach ◽  
Rpv Steel ◽  
Probability Of Fracture

The present study describes a multiscale representation of mechanisms involved in brittle fracture of a french Reactor Pressure Vessel (RPV) steel (16MND5 equ. ASTM A508 Cl.3) at low temperatures. Attention will be focused on the representation of stress heterogeneities inside the ferritic matrix during plastic straining, which is considered as critical for further micromechanical approach of brittle fracture. This representation is tuned on experimental results [1]. Modeling involves micromechanical a description of plastic glide, a mean field (MF) model and a realistic three-dimensional aggregates Finite Element (FE) simulation, all put together inside a multiscale approach. Calibration is done on macroscopic stress-strain curves at different low temperatures, and modeling reproduces experimental stress heterogeneities. This modeling allows to apply a local micromechanical fracture criterion of crystallographic cleavage for triaxial loadings on the Representative Volume Element (RVE). Deterministic computations of time to fracture for different carbide sizes random selection provide a probability of fracture for an Elementary Volume (EV) consistant with the local approach. Results are in good agreement with hypothesis made by local approach to fracture. Hence, the main difference is that no phenomenological dependence on loading or microstructure is supposed for probability of fracture on the EV: this dependence is naturally introduced by the micromechanical description.

scholarly journals Comparison of International Brittle Fracture Design Code Provisions for Steel Bridges

2021 ◽  
pp. 036119812110366
Author(s):  
Michelle Y. X. Chien ◽  
Scott Walbridge ◽  
Bertram Kühn
Keyword(s):  
Brittle Fracture ◽  
Temperature Curve ◽  
Highway Bridge ◽  
Steel Bridge ◽  
Design Code ◽  
Design Rules ◽  
The North ◽  
The World ◽  
Harsh Climate ◽  
Structural Engineers

Brittle fracture is a major concern to structural engineers as it has significant consequences for safety and cost. Although modern day occurrences of brittle fracture are rare, it is well known that they can occur without warning and may lead to the sudden closure of a bridge, loss of service, expensive repairs, and/or loss of property or life. In Canada, steel bridge fracture is a particularly significant concern because of the harsh climate. If the toughness properties are improperly specified, many steels could be on the lower shelf of the toughness-temperature curve. A comparison of brittle fracture design provisions around the world reveals that more sophisticated approaches have been developed for modeling and understanding brittle fracture in existing and new bridges than those currently in use in North America, including Canada and the U.S.A. This paper describes the European brittle fracture provisions and presents a comparison of the North American and European design provisions using the example of a typical steel-concrete composite highway bridge. On the basis of this comparison, situations where one set of design rules may be more or less conservative are identified, and opportunities for improvement and areas warranting further study are highlighted.

scholarly journals Effect of triaxial stress distribution upon roughness of brittle fracture surface

2019 ◽  
Vol 300 ◽  
pp. 11007
Author(s):  
Noritaka Nakamura ◽  
Tomoya Kawabata ◽  
Yasuhito Takashima ◽  
Yuki Nishizono ◽  
Fuminori Yanagimoto
Keyword(s):  
Brittle Fracture ◽  
Fracture Surface ◽  
Main Crack ◽  
Wave Speed ◽  
Stress Triaxiality ◽  
Qualitative Explanation ◽  
Transition Speed ◽  
T Stress ◽  
Starting Speed ◽  
Rayleigh Wave Speed

To observe the effect of stress triaxiality upon brittle fracture surface, we performed two types of experiments which differ in stress triaxiality. As a result, crack branch starting speed changes in two specimens and the speed was affected by stress triaxiality. In bending condition, branch starting speed is around 0.86 cr (cr: Rayleigh wave speed), which is higher than that in tensile condition, 0.59 cr. It was realized that in higher stress triaxiality, branching is easy to occur because in bending condition stress triaxiality is said to be lower. On the other hand, mirror-mist transition speed is not affected by stress triaxiality. By fracture surface observation, we proposed that branch occurs when microbranch grew. This proposition was supported by FEM calculation with microbranch model, it was proved that in bending condition microbranch is difficult to grow. Additionally, we proposed a qualitative explanation that microbranch is easy to grow when stress triaxiality is higher because growth of microbranch is affected by T-stress. It is since the phenomena is not on the main crack propagating plane.

Crack Geometry Effect on Stress-Strain Fields for Crack Under Biaxial Loading

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
Fumiyoshi Minami ◽  
Mitsuru Ohata ◽  
Daisuke Watanabe ◽  
Satoshi Igi ◽  
Takahiro Kubo ◽  
...  
Keyword(s):  
Brittle Fracture ◽  
Surface Crack ◽  
Biaxial Loading ◽  
Large Diameter ◽  
Stress Triaxiality ◽  
Crack Tip ◽  
Ductile Damage ◽  
Strain Fields ◽  
Stress Criterion ◽  
Crack Tip Stress

With increasing demand of high-strength and high-pressure pipelines in gas transmission industries, the fracture control design of pipelines has been a driving factor to ensure the integrity of the pipeline. This paper addresses the stress and strain fields for a crack in a wide plate component under biaxial loading, which simulates a large-diameter pipe subjected to inner pressure coupled with axial loading. Attention is focused on the initiation of brittle fracture (stress controlled type) as well as ductile fracture (strain controlled type). Three-dimensional finite element-analyses are conducted. It was found that biaxial loading has a significant effect on the stress fields of through-thickness crack; the near-crack-tip stress is elevated to a large extent by biaxial loading. By contrast, the stress field for a surface crack is not sensitive to biaxial loading, while the near-crack-tip stress at the crack corner is increased locally by biaxial loading. The Weibull stress criterion was applied to discuss the biaxial loading effect on the brittle fracture strength of the wide plate. Ductile crack initiation properties are also discussed with two-parameter (plastic strain and stress triaxiality) diagram. The ductile damage is increased by biaxial loading for a through-thickness crack, whereas a surface crack has little effect of biaxial loading on the ductile damage.

REQUIRED FRACTURE TOUGHNESS OF STEEL TO PREVENT BRITTLE FRACTURE DURING EARTHQUAKES IN STEEL BRIDGE PIERS

2003 ◽  
pp. 93-102 ◽  
Author(s):  
Eiichi SASAKI ◽  
Taiji ARAKAWA ◽  
Chitoshi MIKI ◽  
Atsushi ICHIKAWA
Keyword(s):  
Fracture Toughness ◽  
Brittle Fracture ◽  
Bridge Piers ◽  
Steel Bridge

BRITTLE-DUCTILE TRANSITION AND SCALE DEPENDENCE: FRACTAL DIMENSION OF FRACTURE SURFACE OF MATERIALS

Fractals ◽  
1999 ◽  
Vol 07 (02) ◽  
pp. 159-168 ◽  
Author(s):  
TOSHITAKA IKESHOJI ◽  
TADASHI SHIOYA
Keyword(s):  
Fractal Dimension ◽  
Brittle Fracture ◽  
Fracture Surface ◽  
Ductile Fracture ◽  
Stress Triaxiality ◽  
Scale Dependence ◽  
Tensile Fracture ◽  
Scanning Electron Micrographs ◽  
Fracture Surfaces ◽  
Brittle Ductile Transition

The fractal dimension of fracture surfaces obtained within brittle-ductile transition regime is evaluated at various observation scales. Fracture surfaces are generated by the tensile fracture test. The brittle-ductile transition is accomplished by using the round-notched bar specimens with various notch radii, which cause the variation in stress triaxiality. The specimens are manufactured from mild steel, steel and cast-iron bar. The fracture model is identified according to the observation through scanning electron micrographs. The fractal dimension for ductile fracture surfaces is almost constant despite variations in observing scale and changes in stress triaxiality. Meanwhile, the fractal dimension on brittle fracture surfaces shows the different values for macroscopic and microscopic observing scales. This transition-like scale dependence of fractal dimension for brittle fracture surfaces is considered to reflect such a characteristic of the fracture i.e. its specific length in microscopic fracture mechanism. The existence of transition in fractal dimension with observing scale is considered to be an index, used to distinguish the ductile fracture surface from the brittle fracture one.

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