FKM Guideline “Fracture Mechanics Proof of Strength for Engineering Components”: Procedures, Compendiums, Examples

2008 ◽  
Author(s):  
Igor Varfolomeyev ◽  
Brita Pyttel
Keyword(s):  
Cyclic Loading ◽  
Fracture Mechanics ◽  
Mechanical Engineering ◽  
Computational Procedure ◽  
Task Group ◽  
Engineering Practice ◽  
Research Committee ◽  
Integrity Assessment ◽  
Component Strength ◽  
Group Component

The German guideline “Fracture Mechanics Proof of Strength for Engineering Components” has been released in 2001 as a result of activities sponsored by the Research Committee on Mechanical Engineering (FKM), task group “Component Strength”. The guideline compiles basics for the integrity assessment of cracked components subjected to static or cyclic loading and provides a step-by-step computational procedure for the use in engineering practice. The paper gives an overview of the guideline, describes its specific features, contents and some new topics included in the last 3rd edition (2006).

Reactor Pressure Vessel Integrity Assessment: French Simplified Analysis Method Applied to Underclad Postulated Defect in Nozzle

2016 ◽  
Author(s):  
Adolfo Arrieta-Ruiz ◽  
Eric Meister ◽  
Stéphane Vidard
Keyword(s):  
Fracture Mechanics ◽  
Fracture Risk ◽  
Pressure Vessel ◽  
Reactor Pressure Vessel ◽  
Core Area ◽  
Integrity Assessment ◽  
Elastic Plastic ◽  
The Core ◽  
Simplified Method ◽  
Reactor Pressure

Structural integrity of the Reactor Pressure Vessel (RPV) is one of the main concerns regarding safety and lifetime of Nuclear Power Plants (NPP) since this component is considered as not reasonably replaceable. Fast fracture risk is the main potential damage considered in the integrity assessment of RPV. In France, deterministic integrity assessment for RPV vis-à-vis the brittle fracture risk is based on the crack initiation stage. As regards the core area in particular, the stability of an under-clad postulated flaw is currently evaluated under a Pressurized Thermal Shock (PTS) through a dedicated fracture mechanics simplified method called “beta method”. However, flaw stability analyses are also carried-out in several other areas of the RPV. Thence-forward performing uniform simplified inservice analyses of flaw stability is a major concern for EDF. In this context, 3D finite element elastic-plastic calculations with flaw modelling in the nozzle have been carried out recently and the corresponding results have been compared to those provided by the beta method, codified in the French RSE-M code for under-clad defects in the core area, in the most severe events. The purpose of this work is to validate the employment of the core area fracture mechanics simplified method as a conservative approach for the under-clad postulated flaw stability assessment in the complex geometry of the nozzle. This paper presents both simplified and 3D modelling flaw stability evaluation methods and the corresponding results obtained by running a PTS event. It shows that the employment of the “beta method” provides conservative results in comparison to those produced by elastic-plastic calculations for the cases here studied.

Fracture Mechanics Based Model for Joints under Cyclic Loading

2006 ◽  
Vol 132 (11) ◽  
pp. 1151-1159 ◽  
Author(s):  
Eric Puntel ◽  
Gabriella Bolzon ◽  
Victor E. Saouma
Keyword(s):  
Cyclic Loading ◽  
Fracture Mechanics

Research of machining forces and technological features of cast PA6, POM C and UHMW-PE HD 1000

2010 ◽  
Vol 1 (1) ◽  
pp. 136-143
Author(s):  
Robert Keresztes ◽  
Gabor Kalacska
Keyword(s):  
Injection Molding ◽  
Cutting Force ◽  
Mechanical Engineering ◽  
Cutting Process ◽  
Engineering Practice ◽  
Serial Production ◽  
Machining Forces ◽  
Engineering Plastics ◽  
Machine Elements ◽  
Cutting Processes

Nowadays parts made of up-to-date engineering plastics are used more and morein mechanical engineering practice. These machine-elements are produced most frequentlyby injection molding or by one cutting process. The injection molding technology are usedgenerally for great number of pieces, in case of serial production while cutting processes arepreferred to piece (unit) or smaller number production.We used lathe and measured the main- and feeding-directional cutting force at differentengineering polymers (cast PA6, POM C and UHMW PE HD 1000). The analysis made canbe well used in practice.

Detailed Transportation Simulation for Improved Logistics Quality

1994 ◽  
Author(s):  
Harry C. Petersen ◽  
Amy Rummel
Keyword(s):  
High Speed ◽  
Mechanical Engineering ◽  
Interdisciplinary Teams ◽  
Control Measures ◽  
Engineering Practice ◽  
Logistics System ◽  
Vehicle Performance ◽  
High Speed Trains ◽  
Transportation Simulation ◽  
Logistics Quality

Abstract This paper demonstrates the advantages of logistics studies which include detailed transportation simulations based on mechanical engineering principles. Complex transportation system parameters are often averaged, aggregated, or assumed, resulting in models with questionable validity. Detailed simulations of route-specific real-world vehicle performance for analysis systems (such as Transport Probability Analysis) can often provide more accurate predictors of logistics system performance, resulting in valid projections of system transport times, costs, inventory levels, energy usage, standards, and quality control measures. A discussion of logistics is followed by examples of progressively complex logistics transportation simulations and models. Results of a moderately detailed performance-based simulation of high speed trains for the Texas Triangle are used to demonstrate the fallacy of assuming “average” performance measures. Future logistics studies will require detailed vehicle performance simulations using sound mechanical engineering practice, requiring interdisciplinary teams which include mechanical engineers.

Assessment of Pipeline Fatigue Crack-Growth Life

2006 ◽  
Author(s):  
Carl E. Jaske
Keyword(s):  
Fatigue Crack ◽  
Cyclic Loading ◽  
Fatigue Crack Growth ◽  
Fracture Mechanics ◽  
Crack Growth ◽  
Flaw Size ◽  
Stress Intensity Factor Range ◽  
Loading History ◽  
Fatigue Crack Growth Life ◽  
Number Of Cycles

This paper describes an accepted approach for predicting fatigue crack-growth life in pipelines. Fatigue life is computed as the number of cycles for a crack-like flaw to grow from an initial size to a final critical size. This computation is performed by integrating a fracture-mechanics model for fatigue crack growth. The initial flaw size is estimated either from inspection results or by using fracture mechanics to predict the largest flaw that would have survived a hydrostatic pressure test. The final flaw size is estimated using fracture mechanics. Fracture-mechanics models for computing fatigue crack growth and predicting flaw size are reviewed. The anticipated cyclic loading must be characterized to perform the crack-growth calculations. Typically, cyclic loading histories, such as pressure cycle data, are analyzed and used to estimate future loadings. To utilize the crack-growth models, the cycles in the loading history must be counted. The rainflow cycle counting procedure is used to characterize the loading history and develop a histogram of load range versus number of cycles. This histogram is then used in the fatigue crack-growth analysis. Results of example calculations are discussed to illustrate the procedure and show the effects of periodic hydrostatic testing, threshold stress intensity factor range, and pressure ratio on predicted fatigue crack-growth life.

Deterministic and Probabilistic Assessments of the Reactor Pressure Vessel Structural Integrity: Benchmark Comparisons

2003 ◽  
Author(s):  
Silvia Turato ◽  
Vincent Venturini ◽  
Eric Meister ◽  
B. Richard Bass ◽  
Terry L. Dickson ◽  
...  
Keyword(s):  
Fracture Mechanics ◽  
Pressure Vessel ◽  
Structural Integrity ◽  
Safety Concern ◽  
Nuclear Regulatory Commission ◽  
Reactor Pressure Vessel ◽  
Oak Ridge ◽  
Integrity Assessment ◽  
Probabilistic Fracture Mechanics ◽  
Reactor Pressure

The structural integrity assessment of a nuclear Reactor Pressure Vessel (RPV) during accidental conditions, such as loss-of-coolant accident (LOCA), is a major safety concern. Besides Conventional deterministic calculations to justify the RPV integrity, Electricite´ de France (EDF) carries out probabilistic analyses. Since in the USA the probabilistic fracture mechanics analyses are accepted by the Nuclear Regulatory Commission (NRC), a benchmark has been realized between EDF and Oak Ridge Structural Assessments, Inc. (ORSA) to compare the models and the computational methodologies used in respective deterministic and probabilistic fracture mechanics analyses. Six cases involving two distinct transients imposed on RPVs containing specific flaw configurations (two axial subclad, two circumferential surface-breaking, and two axial surface-braking flaw configurations) were defined for a French vessel. In two separate phases, deterministic and probabilistic, fracture mechanics analyses were performed for these six cases.

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