A History of the Fractography of Brittle Materials

2009 ◽  
Vol 409 ◽  
pp. 1-16 ◽  
Author(s):  
George D. Quinn
Keyword(s):  
Fracture Mechanics ◽  
Failure Analysis ◽  
State Of The Art ◽  
Brittle Materials ◽  
Fractographic Analysis ◽  
Current State ◽  
History Of ◽  
Scientists And Engineers ◽  
Work Done ◽  
Study Of Fracture Surfaces

The evolution of the science of fractography of brittle materials initially was driven by failure analysis problems. Early analyses focused on general patterns of fracture and how they correlated to the loading conditions. Many early documents are simply descriptive, but the curiosity of some key scientists and engineers was aroused. Scientific or engineering explanations for the observed patterns gradually were developed. Advances in microscopy and flaw based theories of strength and fracture mechanics led to dramatic advances in the state of the art of fractographic analysis of brittle materials. Introduction: This author was drawn backwards in time as he researched the current state of the art of fractographic analysis of brittle materials for his fractography guide book.[ ] Others have written about how the fractographic analysis of metals evolved (e.g., [ , , , ]), but there is no analogue for ceramics and glasses. The key scientists, engineers, and analysts who contributed to our field are shown in Fig. 1. Other work done by industry workers who were unable or loathe to publish is now lost, inaccessible, forgotten, or even discarded. It is the goal of this paper to review the key publications and mark the noteworthy advances in the field. Some deem fractography as the study of fracture surfaces, but this author takes a broader view. Fractography is the means and methods for characterizing fractured specimens or components and, for example, a simple examination of the fragments and how they fit together to study the overall breakage pattern is a genuine fractographic analysis.

The Fatigue Crack Propagation of the Ship Structures in Random Sea States

2012 ◽  
Author(s):  
Guoqing Feng ◽  
Junwei Cao ◽  
Huilong Ren ◽  
Hui Li
Keyword(s):  
Fatigue Strength ◽  
Fracture Mechanics ◽  
Traditional Method ◽  
Stress Cycle ◽  
Stress History ◽  
Ship Structures ◽  
Strength Assessment ◽  
Fatigue Stress ◽  
History Of ◽  
Fatigue Strength Assessment

The traditional method for the fatigue strength assessment of ship structures is based on S-N curves and Miner linear cumulative damage rules. However, with the development of the ship mechanics, the fracture mechanics method has aroused people’s attention. Some researchers have begun to use the fracture mechanics method to perform the fatigue strength assessment of ship structures. A fracture mechanics based approach for the fatigue assessment of ship structures in random sea states is presented. First, the fatigue stress history of the ship structures in random sea states is simulated. Then, the stress intensity factor in random sea states is calculated through the weight function and the fatigue stress of the ship structures in random sea states. Finally, the crack growth is calculated using Pairs equation for each stress cycle throughout the fatigue stress history of the ship structures in random sea states.

scholarly journals DAMAGE AND FRACTURE MECHANICS CONCEPTS IN CALCULATING CYCLICALLY LOADED PRESSURE EQUIPMENT

2016 ◽  
Vol 19 (2) ◽  
Author(s):  
VALI-IFIGENIA IORDĂCHESCU (NICOLOF) ◽  
TEODOR SIMA
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Fracture Mechanics ◽  
Crack Tip Opening Displacement ◽  
Opening Displacement ◽  
Damage And Fracture ◽  
History Of ◽  
Mechanics Concepts ◽  
Crack Tip Opening ◽  
Weld Seams

<p>In the history of technology there occurred many accidents caused by the presence and propagation of cracks in a mechanical structure, especially cracks in weld seams or already existing in the material. The paper evaluates the damage caused by cracks, the superposition of effects by using fracture mechanics concepts (the stress intensity factor, the contour integral and the crack tip opening displacement), while in the case of superposition fracture modes I and II , the relation was checked against the experimental literature data.</p>

Calculations to Benchmark Probabilistic Fracture Mechanics Computer Codes

2007 ◽  
Author(s):  
F. A. Simonen ◽  
S. R. Gosselin ◽  
G. M. Wilkowski ◽  
D. L. Rudland ◽  
H. Xu
Keyword(s):  
Water Stress ◽  
Fracture Mechanics ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Operating Conditions ◽  
Component Failure ◽  
Probabilistic Fracture Mechanics ◽  
Primary Water ◽  
History Of ◽  
Computer Codes

This paper describes calculations to estimate component failure frequencies for components using the PRO-LOCA and PRAISE probabilistic fracture mechanics (PFM) computer codes. Other PFM codes are also described along with prior benchmarking efforts. The calculations of this paper focus on the failure mechanism of primary water stress corrosion cracking for operating conditions that were known to have failed field components. The objective was to benchmark the newly developed PRO-LOCA code against the older PRAISE code that had a much longer history of prior applications. It was established that advanced modeling capabilities in the PRO-LOCA code simulated parameters that were treated deterministically by the PRAISE code. Excellent agreement of numerical results from the two codes was established once the PRO-LOCA code was applied using selective deterministic treatments.

scholarly journals Path selection in the growth of rivers

2015 ◽  
Vol 112 (46) ◽  
pp. 14132-14137 ◽  
Author(s):  
Yossi Cohen ◽  
Olivier Devauchelle ◽  
Hansjörg F. Seybold ◽  
Robert S. Yi ◽  
Piotr Szymczak ◽  
...  
Keyword(s):  
Fracture Mechanics ◽  
Single Channel ◽  
Local Environment ◽  
Path Selection ◽  
River Networks ◽  
Diffusion Field ◽  
Drainage Network ◽  
Flow Conditions ◽  
Local Flow ◽  
History Of

River networks exhibit a complex ramified structure that has inspired decades of studies. However, an understanding of the propagation of a single stream remains elusive. Here we invoke a criterion for path selection from fracture mechanics and apply it to the growth of streams in a diffusion field. We show that, as it cuts through the landscape, a stream maintains a symmetric groundwater flow around its tip. The local flow conditions therefore determine the growth of the drainage network. We use this principle to reconstruct the history of a network and to find a growth law associated with it. Our results show that the deterministic growth of a single channel based on its local environment can be used to characterize the structure of river networks.

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