Fracture mechanics in design and service: ‘living with defects’ - Elastic—plastic aspects of fracture stress analysis: methods for other than standardized test conditions

1981 ◽  
Vol 299 (1446) ◽  
pp. 73-92 ◽  
Keyword(s):  
Fracture Mechanics ◽  
Stress Analysis ◽  
Fracture Stress ◽  
Standardized Test ◽  
Elastic Plastic ◽  
Test Conditions ◽  
Analysis Methods

scholarly journals In-situ elastic-plastic fracture mechanics on the microscale by means of continuous dynamical testing

2018 ◽  
Vol 148 ◽  
pp. 177-187 ◽  
Author(s):  
Markus Alfreider ◽  
Darjan Kozic ◽  
Otmar Kolednik ◽  
Daniel Kiener
Keyword(s):  
Fracture Mechanics ◽  
Elastic Plastic

Comparative study of stress analysis of gears with different helix angle using the ISO 6336 standard and tooth contact analysis methods

2016 ◽  
Vol 230 (7-8) ◽  
pp. 1350-1358 ◽  
Author(s):  
Layue Zhao ◽  
Robert C Frazer ◽  
Brian Shaw
Keyword(s):  
Stress Analysis ◽  
Contact Stress ◽  
Helix Angle ◽  
Contact Analysis ◽  
Bending Stress ◽  
Contact Ratio ◽  
Tooth Contact Analysis ◽  
Tooth Contact ◽  
Iso Standard ◽  
Analysis Methods

With increasing demand for high speed and high power density gear applications, the need to optimise gears for minimum stress, noise and vibration becomes increasingly important. ISO 6336 contact and bending stress analysis are used to determine the surface load capacity and tooth bending strength but dates back to 1956 and although it is constantly being updated, a review of its performance is sensible. Methods to optimise gear performance include the selection of helix angle and tooth depth to optimise overlap ratio and transverse contact ratio and thus the performance of ISO 6336 and tooth contact analysis methods requires confirmation. This paper reviews the contact and bending stress predicted with four involute gear geometries and proposes recommendations for stress calculations, including a modification to contact ratio factor Zɛ which is used to predict contact stress and revisions to form factor YF and helix angle factor Yβ which are cited to evaluate bending stress. The results suggest that there are some significant deviations in predicted bending and contact stress values between proposal methods and original ISO standard. However, before the ISO standard is changed, the paper recommends that allowable stress numbers published in ISO 6336-5 are reviewed because the mechanisms that initiate bending and contact fatigue have also changed and these require updating.

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.

3-D FE analyses of WRS and simplified elastic-plastic fracture mechanics assessment of a repaired weld

2019 ◽  
Vol 341 ◽  
pp. 124-136 ◽  
Author(s):  
Chen Mingya ◽  
Yu Weiwei ◽  
Xue Fei ◽  
Ku Francis ◽  
Chen Zhilin ◽  
...  
Keyword(s):  
Fracture Mechanics ◽  
Elastic Plastic

Prediction of Brittle Fracture Under Generalised Elastic Plastic Loading

2008 ◽  
Author(s):  
S. J. Lewis ◽  
C. E. Truman ◽  
D. J. Smith
Keyword(s):  
Fracture Mechanics ◽  
Brittle Fracture ◽  
Ferritic Steel ◽  
Failure Prediction ◽  
J Integral ◽  
Local Approach ◽  
Elastic Plastic ◽  
Failure Data ◽  
Stress States ◽  
Plastic Loading

This article describes an investigation into the ability of a number of different fracture mechanics approaches to predict failure by brittle fracture under general elastic/plastic loading. Data obtained from C(T) specimens of A508 ferritic steel subjected to warm pre-stressing and side punching were chosen as such prior loadings produce considerably non-proportionality in the resulting stress states. In addition, failure data from a number of round notched bar specimens of A508 steel were considered for failure with and without prior loading. Failure prediction, based on calibration to specimens in the as received state, was undertaken using two methods based on the J integral and two based on local approach methodologies.

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