A probabilistic fracture mechanics approach for structural reliability assessment of space flight systemsSutharshana, S., Ebbeler, D., Moore, N. and Creager, M. Proc. Conf. Advances in Fatigue Lifetime Predictive Techniques, San Francisco, California, USA, 24 Apr. 1990 234–246

1993 ◽  
Vol 15 (1) ◽  
pp. 66-66
Keyword(s):  
Fracture Mechanics ◽  
San Francisco ◽  
Space Flight ◽  
Structural Reliability ◽  
Reliability Assessment ◽  
Fatigue Lifetime ◽  
Probabilistic Fracture Mechanics

Reliability assessment of structures based upon probabilistic fracture mechanics

1993 ◽  
Vol 8 (1) ◽  
pp. 43-56 ◽  
Author(s):  
Hiroshi Ishikawa ◽  
Akira Tsurui ◽  
Hiroaki Tanaka ◽  
Hidetoshi Ishikawa
Keyword(s):  
Fracture Mechanics ◽  
Reliability Assessment ◽  
Probabilistic Fracture Mechanics

Probabilistic Fracture Mechanics Structural Reliability Analysis of Reeled Pipes

2006 ◽  
Author(s):  
Hugo A. Ernst ◽  
Ricardo Schifini ◽  
Richard E. Bravo ◽  
Diego N. Passarella ◽  
Federico Daguerre ◽  
...  
Keyword(s):  
Fracture Mechanics ◽  
Reliability Analysis ◽  
Structural Reliability ◽  
Crack Size ◽  
Probability Of Failure ◽  
Statistical Distribution ◽  
Assessment Procedure ◽  
Statistical Distributions ◽  
Probabilistic Fracture Mechanics ◽  
Structural Reliability Analysis

Structural integrity analyses are used to guarantee the reliability of critical engineering components under certain conditions of interest. In general, the involved parameters have statistical distributions. Choosing a single set of values for the parameters of interest does not show the real statistical distribution of the output parameters. In particular, offshore pipes installation by reeling is a matter of concern due to the severe conditions of the process. Since it is necessary to guarantee the integrity of the pipes, a probabilistic fracture mechanics reliability analysis seems to be the most adequate approach. In this work, a probabilistic fracture mechanics assessment approach to perform the structural reliability analysis of tubes subjected to a reeling process was developed. This procedure takes into account the statistical distributions of the material properties and pipe geometry, using a fracture mechanics approach and the Monte Carlo method. Two-parameter Weibull distributions were used to model the variability of the input parameters. The assessment procedure was implemented as a self-contained executable program. The program outputs are: the statistical distribution of critical crack size, amount of crack extension, final crack size and the cumulative probability of failure for a given crack size. A particular case of interest was studied; a seamless tube - OD 323.9 × wt 14.3 mm, was analyzed. Tolerable defect size limits (defect depth vs. defect length curves) for different probability of failure levels were obtained. A sensitivity analysis was performed; the effect of material fracture toughness and misalignment was studied.

Probabilistic Prediction of Crack Depth Distributions Observed in Structures Subjected to Thermal Fatigue

2006 ◽  
Author(s):  
Tai Asayama ◽  
Hideki Takasho ◽  
Takehiko Kato
Keyword(s):  
Fracture Mechanics ◽  
Thermal Fatigue ◽  
Structural Reliability ◽  
Evaluation Method ◽  
Crack Depth ◽  
Inspection Planning ◽  
Probabilistic Fracture Mechanics ◽  
Nuclear Plants ◽  
Depth Distributions ◽  
Failure Probabilities

The application of risk-based technologies not only to inservice inspections but also to the design of components and systems, encompassing a plant life-cycle, is the way to be pursued for the improvement of design of new reactors such as fast breeder reactors. When doing so it is necessary to develop an analytical method that is capable of estimating failure probabilities without a failure database that can only be established on the long-time accumulation of operational experiences. The prediction method should estimate failure probabilities based on actual mechanisms that cause failure. For this purpose, this study developed a probabilistic structural reliability evaluation method for fatigue which is a representative failure mode to be prevented in components of nuclear plants. This method is an extension of probabilistic fracture mechanics approach but is capable of modeling crack initiation, crack propagation, as well as crack depth density distribution at a given cycle. To verify the methodology, crack depth distribution observed in thermal fatigue test specimens were evaluated, and it was shown that the method could reproduce the observed crack depth distributions fairly well. This is considered to explore the possibility that probabilistic fracture mechanics approach can be verified by experiments, which was deemed impossible so far. Further improvement such as explicit implementation of interaction mechanisms between adjacent cracks will allow this methodology to be applied to the procedure of optimization of inservice inspection planning, as well as to the optimization of safety factors in component design of nuclear plants.

Probabilistic Fracture Mechanics Methodology Applied to Pipes Subjected to Multiple Reeling Cycles

2007 ◽  
Author(s):  
Hugo A. Ernst ◽  
Richard E. Bravo ◽  
Ricardo Schifini ◽  
Diego N. Passarella
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Fracture Mechanics ◽  
Reliability Analysis ◽  
Crack Growth ◽  
Structural Reliability ◽  
Probabilistic Fracture Mechanics ◽  
Assessment Approach ◽  
Pipe Geometry ◽  
Cyclic Plastic Deformation

Reeling process is one of the more used methods for installations of linepipes in recent years. Pipes are welded onshore and subsequently reeled onto a drum. During installation, the line is unreeled, straightened, and then laid into the sea. The pipe is subjected to severe cyclic plastic deformation. Due to the characteristics of the process, it is necessary to guarantee the integrity of the components during and after the process. For this reason, structural reliability analyses are essential requirements. In a previous work [1], a fracture mechanics based methodology was developed to obtain a method to assess the structural reliability of reeled pipes. The problem of several reeling cycles was considered. In addition to a fracture mechanics methodology, a formulation considering fatigue crack growth (FCG) controlled by ΔJ parameter was developed. This formulation accounts for the crack growth produced during subsequent reeling cycles. In another work [2], a probabilistic fracture mechanics assessment approach to perform the structural reliability analysis of tubes subjected to a reeling process was developed. This procedure takes into account the statistical distributions of the material properties and pipe geometry, using a fracture mechanics approach and the Monte Carlo method. In this work, the probabilistic fracture mechanics approach was applied for the case of multiple reeling cycles that includes ΔJ-based fatigue crack growth and reliability analysis. A particular case of interest was studied and tolerable defect sizes were determined for different number of reeling cycles taking into account the parameters variability.

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