Determination of critical defect size for delamination failure of the pad/encapsulant interface of plastic IC packages undergoing solder reflow

2004 ◽  
Author(s):  
A.A.O. Tay ◽  
Y.Y. Ma
Keyword(s):  
Defect Size ◽  
Critical Defect ◽  
Solder Reflow ◽  
Critical Defect Size ◽  
Delamination Failure

Use of Nuclear Mechanical Design Codes and Fracture Mechanics Procedures for the UK EPR™ at Hinkley Point C

2013 ◽  
Author(s):  
Martin Gallegillo ◽  
Andrew Goodfellow ◽  
Christophe Philipp ◽  
Lol Miles ◽  
Anthony Williams
Keyword(s):  
Fracture Mechanics ◽  
Structural Integrity ◽  
Mechanical Design ◽  
Defect Size ◽  
Critical Defect ◽  
Safety Case ◽  
Asme Code ◽  
Critical Defect Size ◽  
The Uk

Structures, systems and components that are important to nuclear safety are designed, manufactured, constructed, installed, commissioned, quality assured, maintained, tested and inspected to the appropriate standards. The codes and standards need to be evaluated to determine their applicability, adequacy and sufficiency. The consideration of a conservative design is one important element of the Safety Case. This is generally used together with high manufacturing quality, the use of proven materials, inspection, functional testing and defect tolerability. In a UK Safety Case, the assessment of fracture risk of those mechanical components whose likelihood of gross failure is so low that can be discounted requires the determination of the actual critical defect size in order to compare it with the detectable defect size used for inspections. For the UK EPR™ the 2007 Edition of the RCC-M Code including Addenda 2008, 2009 and 2010 will be the design code of reference and the RSE-M Code version 2010 Appendix 5 will form the basis of the methodology used for standard fracture mechanics assessments of the UK EPR™. Previously, the UK nuclear structural integrity community has used the ASME Code Section III for the UK previous PWR and the R6 procedure for fracture mechanics assessments. This paper explains the choice of these two codes for the UK EPR™ and the work carried out to date by EDF Energy to demonstrate its compliance with the UK expectations for components critical to safety.

Effect of the Yield to Tensile Ratio, Y/T, on Structural Reliability of Linepipes

2003 ◽  
Author(s):  
Hugo A. Ernst ◽  
Jose´ A. Villasante ◽  
Alfonso Izquierdo
Keyword(s):  
Structural Reliability ◽  
Plasticity Theory ◽  
Defect Size ◽  
Defect Tolerance ◽  
Deformation Control ◽  
Critical Defect ◽  
Control Situations ◽  
Critical Defect Size ◽  
T Values ◽  
Lower Limits

The effect of the Yield (Y) to Tensile (T) ratio, Y/T, on the structural reliability of linepipes with longitudinal defects was studied in this work. A model based on elastic-plastic fracture mechanics (EPFM) and plasticity theory, was developed for that purpose. The analysis allows for load or deformation control situations. The results are shown in terms of curves of critical defect size vs. the controlling variable, i.e. load or deformation. For each one of the several materials studied, different cases with different Y/T values were considered. Even for the lower limits of experimental data, i.e. larger Y/T, the materials have adequate defect tolerance.

Investigation of the Improvements on Mechanical Properties and Thermal Performance of MgO-MgAl2O4 Composite Refractories by Additions of ZnO-Al2O3 to MgO

2012 ◽  
Vol 445 ◽  
pp. 530-535 ◽  
Author(s):  
Cemail Aksel
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Thermal Performance ◽  
Industrial Applications ◽  
Sem Analysis ◽  
Defect Size ◽  
Structural Variations ◽  
Factors Affecting ◽  
Critical Defect ◽  
Critical Defect Size

The variations and developments with the reasons on the mechanical properties of MgO-MgAl2O4 and MgO-ZnO-Al2O3 composite refractories were examined and thermal parameters affecting the durability of composites at high temperatures were investigated. The density, porosity, strength, modulus of elasticity, fracture toughness, fracture surface energy, critical defect size and mean MgO grain size values of composites were measured/calculated and evaluated. In addition, microstructural changes using XRD measurements and SEM analysis were examined. Thermal stress/shock parameters R and Rst that are used for determining high temperature performance of composites were calculated. The relationships between mechanical properties and structural variations for different compositions and the factors affecting this connection were investigated. With the additions of various amounts of ZnO-Al2O3 to MgO, significant improvements were achieved on both mechanical properties and R-Rst parameters of in-situ formed M-S-ZnAl2O4 composite refractories, compared to MgO-MgAl2O4 materials containing preformed spinel, by factors of up to 3.6 and 2.0, respectively. The important parameters increasing mechanical properties and thermal performance of M-S-ZnAl2O4 composites were determined as follows: i) formation of ZnAl2O4 phase leading to a high resistance to crack initiation and propagation, ii) propagation of microcracks formed in the structure for a short distance by interlinking to each other, iii) arresting or deviation of microcracks when reaching pores or ZnAl2O4 particles, and additionally iv) co-presence of both intergranular and transgranular types of cracks on fracture surfaces, and with the incorporations of ZnO-Al2O3, v) increase in density, vi) rise in critical defect size, and vii) a significant reduction in MgO grain size. The optimisation of M-S-ZnAl2O4 composite refractories that could be used for obtaining longer service life in industrial applications was performed.

Evaluation of the static cracking resistance of the metal calculating the critical defect size in bands of large compound support rolls

1990 ◽  
Vol 26 (2) ◽  
pp. 176-182
Author(s):  
O. N. Romaniv ◽  
Yu. A. Grushko ◽  
N. A. Adamova ◽  
A. N. Takach ◽  
T. Ra. Yus'kiv ◽  
...  
Keyword(s):  
Defect Size ◽  
Cracking Resistance ◽  
Critical Defect ◽  
Critical Defect Size ◽  
Large Compound

Critical Defect Size for Osteochondral Lesions of the Talus: Letter to the Editor

2012 ◽  
Vol 40 (9) ◽  
pp. NP23-NP24
Author(s):  
Charles P. Hannon ◽  
Christopher D. Murawski ◽  
Niall A. Smyth ◽  
John G. Kennedy
Keyword(s):  
Defect Size ◽  
Osteochondral Lesions ◽  
Letter To The Editor ◽  
Critical Defect ◽  
Critical Defect Size

Effect of the Yield to Tensile Ratio on Structural Integrity of Linepipes Subjected to Internal Pressure

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
Hugo A. Ernst ◽  
Richard E. Bravo ◽  
José A. Villasante ◽  
Alfonso Izquierdo
Keyword(s):  
Internal Pressure ◽  
Structural Integrity ◽  
Defect Size ◽  
Defect Tolerance ◽  
Deformation Control ◽  
Critical Defect ◽  
Control Situations ◽  
Critical Defect Size ◽  
T Values ◽  
Lower Limits

The effect of the yield (Y) to tensile (T) ratio Y∕T on the structural integrity of linepipes with part through the thickness longitudinal defects subject to internal pressure was studied in this work. A model based on elastic-plastic fracture mechanics and plasticity theory was developed for that purpose. The analysis allows for load or deformation control situations. The results are shown in terms of curves of critical defect size versus the controlling variable, i.e., load or deformation. For each one of the several materials studied, different cases with different Y∕T values were considered. Even for the lower limits of experimental data, i.e., larger Y∕T, the materials have adequate defect tolerance.

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