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

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 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.

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