Measured strains correction for eccentric holes in the determination of non-uniform residual stresses by the hole drilling strain gauge method

2017 ◽  
Vol 132 ◽  
pp. 302-313 ◽  
Author(s):  
D. Peral ◽  
C. Correa ◽  
M. Diaz ◽  
J.A. Porro ◽  
J. de Vicente ◽  
...  
Keyword(s):  
Residual Stresses ◽  
Strain Gauge ◽  
Hole Drilling

Residual Stress Analysis in Containers for Transport of Radioactive Materials

2015 ◽  
Vol 732 ◽  
pp. 28-31 ◽  
Author(s):  
František Trebuňa ◽  
František Šimčák ◽  
Miroslav Pástor ◽  
Patrik Šarga
Keyword(s):  
Residual Stresses ◽  
Experimental Methods ◽  
Hole Drilling ◽  
Thermal Processes ◽  
Safe Operation ◽  
Radioactive Materials ◽  
Hole Drilling Method ◽  
Drilling Method ◽  
Residual Stress Analysis

During verification of safe operation of containers for radioactive waste is possible to use analytical, numerical and experimental methods of mechanics. Determination of residual stresses was one part of analysis. The residual stresses in container body can be induced during their production, overloading during operation, radiation or by thermal processes. In the paper are presented results from analysis of residual stresses in containers by using strain-gage hole-drilling method.

USE OF THE HOLE DRILLING METHOD TO DETERMINE RESIDUAL WELD STRESSES IN BRIDGE CONSTRUCTIONS

2016 ◽  
Vol 3 (1) ◽  
Author(s):  
Evy Van Puymbroeck ◽  
Wim Nagy ◽  
Hans De Backer
Keyword(s):  
Yield Strength ◽  
Residual Stresses ◽  
Strain Gauge ◽  
Bridge Deck ◽  
Hole Drilling ◽  
Steel Bridge ◽  
Weld Region ◽  
Longitudinal Stiffener ◽  
Deck Plate ◽  
Compressive Residual Stresses

Complex welding operations in orthotropic steel bridge decks introduce residual stresses near the weld region. To estimate fatigue failure of this type of bridge deck, tensile residual yield stresses are usually assumed around the weld region. However, to estimate the residual stress distribution near a weld connection more precisely, a test setup is developed. The weld connection of a closed longitudinal trapezoidal stiffener with the deck plate of an orthotropic bridge deck is investigated. The incremental hole-drilling technique is used to measure the residual stresses with strain gauge rosettes. Strain gauge rosettes are positioned on the deck plate and on a longitudinal stiffener of the orthotropic steel deck. A small hole is drilled through the center of the strain gauge rosettes and strains are measured at incremental depths. The residual stresses are calculated and based on these experimental measurements a distribution of the residual stresses is obtained. Compressive residual stresses exist near the longitudinal stiffener-to-deck plate weld. On the deck plate, the compressive residual stresses are equal to 60% of the yield strength while the compressive residual stresses on the stiffener are 42% of the yield strength. There are tensile residual stresses on both sides of the weld region. However, more research is necessary to confirm this distribution since it is contradictory to expected stresses in literature.

A Study of Process-Induced Residual Stress in PBGA Packages

1999 ◽  
Vol 122 (3) ◽  
pp. 262-266 ◽  
Author(s):  
Zhu Wu ◽  
Jian Lu ◽  
Yifan Guo
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Electronic Packaging ◽  
Accurate Determination ◽  
Hole Drilling ◽  
3D Fem ◽  
Molding Compound ◽  
Plastic Ball ◽  
Calibration Coefficients

Process-induced residual stresses can play a significant role in the reliability of electronic components and packages. In this paper, a practical method is developed to determine residual stresses for electronic packaging. In this method, blind holes are drilled into the specimens and relationships are established, between the released surface displacements and the corresponding residual stress, by introducing a set of calibration coefficients. A multilayer 3D-FEM model is established to determine the relevant calibration coefficients. This methodology, which combines moire´ interferometry and the incremental hole drilling method, can provide an accurate determination of residual stresses in materials and structures by precisely controlled incremental blind-hole drilling and an accurate determination of the surface in-plane displacement fields in the hole drilling region. The methodology is implemented by investigating the residual stress in the Plastic Ball Grid Array (PBGA) packages. The tensile residual stresses are determined in both the plastic molding compound and the glass/epoxy laminate chip carrier. The method is accurate, simple, convenient, and practical. More applications, in residual stress determinations and in process evaluations in electronic packaging, are anticipated. [S1043-7398(00)00103-1]

Residual Stresses Evaluation on Radial Friction Welded Joints

2005 ◽  
Author(s):  
Rosa Irene Terra Pinto ◽  
Telmo Roberto Strohaecker
Keyword(s):  
Residual Stresses ◽  
Friction Welding ◽  
Deformation Gradient ◽  
Welding Process ◽  
Hole Drilling ◽  
Welding Parameters ◽  
Hole Drilling Method ◽  
Joint Quality ◽  
Welding Processes

The Radial Friction Welding (RFW) is a solid-state welding process in which two long elements of several metallic alloys can be joined, without the occurrence of common problems to the conventional welding processes that include fusion. During friction welding the temperature evolution is directly related with the deformation gradient, and these fields govern the joint properties. In this work, the finite element method was used to solve the full coupled termomechanical problem in order to determine the deformation and the stress fields and the variation of the temperature during RFW process. The simulation of the RFW process permitted to establish the influence of the welding parameters, like rotation and approximation speed, on the joint quality. Furthermore, the knowledge of the temperature gradient and cooling rates allowed the prediction of the resulting microestruture and determination of the level of residual stresses of the joint. To verify the analytical results the determination of the residual stresses was accomplished by the hole drilling method in several points along the perimeter of two welded workpieces.

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