Experimental and numerical study of measuring high welding residual stresses by using the blind-hole-drilling technique

2008 ◽  
Vol 43 (3) ◽  
pp. 141-148 ◽  
Author(s):  
R Moharami ◽  
I Sattari-Far
2006 ◽  
Vol 514-516 ◽  
pp. 768-773
Author(s):  
Joao P. Nobre ◽  
Altino Loureiro ◽  
António Castanhola Batista ◽  
A. Morão Dias

In this work the reliability of the hole-drilling technique (HDT) for measuring welding residual stresses was analysed. HDT residual stress results were systematically compared with those determined by X-ray diffraction. A systematic overestimation of the residual stresses determined by HDT was observed, which was mainly attributed to the possibility of the so-called plasticity effect occurring. Experimental results were discussed taking the measurement principles of both techniques into consideration. In addition, preliminary results of a numerical study, using the finite element method, will be presented for a better understanding of the plasticity effect on HDT residual stress results.


2021 ◽  
Author(s):  
ARTURO LEOS ◽  
KOSTIANTYN VASYLEVSKYI ◽  
IGOR TSUKROV ◽  
TODD GROSS ◽  
BORYS DRACH

Manufacturing-induced residual stresses in carbon/epoxy 3D woven composites arise during cooling after curing due to a large difference in the coefficients of thermal expansion between the carbon fibers and the epoxy matrix. The magnitudes of these stresses appear to be higher in composites with high throughthickness reinforcement and in some cases are sufficient to lead to matrix cracking. This paper presents a numerical approach to simulation of development of manufacturing-induced residual stresses in an orthogonal 3D woven composite unit cell using finite element analysis. The proposed mesoscale modeling combines viscoelastic stress relaxation of the epoxy matrix and realistic reinforcement geometry (based on microtomography and fabric mechanics simulations) and includes imaginginformed interfacial (tow/matrix) cracks. Sensitivity of the numerical predictions to reinforcement geometry and presence of defects is discussed. To validate the predictions, blind hole drilling is simulated, and the predicted resulting surface displacements are compared to the experimentally measured values. The validated model provides an insight into the volumetric distribution of residual stresses in 3D woven composites. The presented approach can be used for studies of residual stress effects on mechanical performance of composites and strategies directed at their mitigation.


2013 ◽  
Vol 53 (7) ◽  
pp. 1223-1231 ◽  
Author(s):  
A. H. Mahmoudi ◽  
G. Zheng ◽  
D. J. Smith ◽  
C. E. Truman ◽  
M. J. Pavier

Author(s):  
Wim Nagy ◽  
Philippe Van Bogaert ◽  
Hans De Backer

Manufacturing processes such as welding operations cause residual stresses that are present in most civil structures. They cause plastic deformations without any external loads and are therefore often overlooked during design. Nevertheless, residual stresses can have profound influences on material strength and fatigue life. This is also true for orthotropic steel bridge decks, which have many complex welding details. Because little is known about the distribution of residual stresses due to welding, a semi-destructive experimental test setup is developed for a stiffener-to-deck plate connection on an orthotropic steel bridge deck. In particular, the hole-drilling technique is used. With this experimental test setup, a clear distribution of the residuals stresses becomes visible. Residual stresses up to the yield strength can be found near the weld and up to 50% of the yield strength elsewhere. However, more research is needed to verify why the sign of the stresses is opposite to the expected stresses in the literature.


Author(s):  
Gang Zheng ◽  
Sayeed Hossain ◽  
Feng Shen ◽  
Chris Truman

The aim of the present study was to utilize a complex residual stress generated within a welded circular disc to further investigate the standard deep-hole drilling (DHD) technique and the newly developed over-coring deep-hole drilling (oDHD) technique in accurately measuring residual stresses well over yield stress. Finite Element Analysis (FEA) was used to optimize and extend the deep-hole drilling technique and improve its accuracy. The standard DHD procedure involves 4 steps. (1) A reference hole is gun-drilled through the component. (2) The internal diameter of the reference hole is measured at different angular positions through the depth of the component. (3) A cylindrical section with the reference hole as its longitudinal axis is trepanned free from the component. (4) Finally, the relaxed internal diameter is re-measured at the same angular positions and the same depths. The drilling, trepanning procedures and the parameters of the deep-hole drilling technique were all studied in detail to optimize the technique. Comparison is made between the FEA predicted residual stress in the weld, the measurements and the reconstructed residual stresses of the measurements. The close correlations confirmed the suitability of new modifications made in the deep-hole drilling technique to account for plasticity when measuring near yield residual stresses present in a component.


2013 ◽  
Vol 768-769 ◽  
pp. 101-106
Author(s):  
Harri Lille ◽  
Jakub Kõo ◽  
Jaak Valgur ◽  
Alexander Ryabchikov ◽  
Renno Reitsnik ◽  
...  

The paper presents a method for measuring residual stresses in normal thermo-bimetal Fe-Ni-Mn/Invar strips with a thickness of 0.76 mm. For this purpose, a setup was designed which permits to remove layers from a strip substrate by electrochemical etching. Residual stresses in the directions that are longitudinal and transversal to rolling are determined by the curvature method based on the layer growing/removing techniques. As a reference, residual stresses were also determined by hole-drilling technique. Tensile and compressive residual stresses arose both in active and in passive layers and were considerably higher when determined by the hole-drilling technique.


Author(s):  
S. Hossain ◽  
C. E. Truman ◽  
D. J. Smith ◽  
M. R. Daymond

This paper presents results from an experimental and numerical study examining the creation of highly triaxial residual stresses in stainless steel. This was motivated by a need to model and understand creep in aged power plant. The residual stresses were introduced by rapid spray water quenching of heated solid stainless steel spheres and cylinders. Finite element (FE) simulations predicted high compressive residual stresses around the surface of the specimens and tensile residual stresses near the centre. Surface residual stresses were measured using the incremental centre-hole drilling (ICHD) technique. Neutron diffraction (ND) was used to measure the interior residual stresses. The measurements were in good agreement with FE predictions. The ND measurements confirmed that a highly triaxial residual stress state existed in the core of the specimens.


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