Residual Stress Measurements of Cylindrical Parts by Hole Drilling Strain Gage Method

2013 ◽  
Vol 311 ◽  
pp. 462-466
Author(s):  
Chia Lung Chang ◽  
Yan Huo Kao ◽  
You Lung Jao ◽  
Chih Laing Chang

Hole drilling strain gage method is a semi-destructive measurement. The method is most commonly used to measure residual stresses. The relieved strains are measured around the drilled hole, and the residual stresses are estimated by the mechanical relationship between relieved strains and residual stresses as well calibration coefficients. The calibration coefficients indicate the relieved strains due to unit stresses within the hole depth. Finite element method is always used to determine the calibration coefficients, and the analytical model is based on the infinite plate. But the geometrical shape and size of cylindrical part are different from the infinite plate. The relieved strains around the drilled hole are different too. Finite element model of the cylindrical part is constructed to obtain the hole drilling calibration coefficients. The measurement of residual stresses in a cylindrical part subject to axial loading calculated by calibration coefficients of both infinite plate and cylindrical part model are compared to show the difference.

2019 ◽  
Vol 13 (1) ◽  
pp. 4536-4557 ◽  
Author(s):  
K. Azizpour ◽  
H. Moshayedi ◽  
I. Sattari-far

Tensile residual stress is a major issue in integrity of the welded structures. Undesirable tensile residual stress in welding may reduce fracture toughness and fatigue life of welded structures. The low transformation-temperature (LTT) fillers, due to introducing compressive residual stresses caused by prior martensitic transformation, can reduce tensile residual stresses in the weld zone. The effects of using LTT fillers on welding residual stresses of high strength steel sheets are studied and compared with conventional fillers. 3D finite element simulations including coupled thermal-metallurgical-mechanical analyses are developed using SYSWELD software to predict the welding residual stresses. For validation of the finite element model, the residual stresses are measured through hole drilling strain gage method. The results indicate that using the LTT fillers cause a decrease of the longitudinal tensile residual stresses of the weld metal from 554 MPa to 216 MPa in comparison with conventional fillers. The transverse residual stresses of the weld line are changed from tensile 156 MPa to compressive 289 MPa with using LTT fillers instead of conventional fillers.


Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 708
Author(s):  
Maribel Hernández ◽  
Ricardo R. Ambriz ◽  
Christian García ◽  
David Jaramillo

The gas metal arc welding (GMAW) process was used to weld 3003-H14 plates under restricted and unrestricted thermal expansion. Experimental and numerical analysis were conducted to determine the relation between weld thermal cycles and residual stresses. A customized data acquisition system with K-type thermocouples was used to measure the weld thermal cycles, while residual stresses were determined by the hole drilling method. Thermo-mechanical simulation models for the two restricted conditions were implemented from the experimental data obtained. A double ellipse heat distribution geometry was used to model the heat moving source by using the finite element method. Thermal rates and peak temperatures were approximated by the finite element model with 2% difference, with respect to the experimental weld thermal cycles. Longitudinal and transverse normal residual stresses determined by the finite element model showed a good comparison with experimental measurements. The larger residual stresses were in the transverse direction for both clamping conditions, which indicated that working loading paths along the lateral direction of the welded plate are more influenced by the post-welding residual stresses.


1985 ◽  
Vol 107 (4) ◽  
pp. 349-354 ◽  
Author(s):  
J. S. Strenkowski ◽  
J. T. Carroll

A finite element model of orthogonal metal cutting is described. The paper introduces a new chip separation criterion based on the effective plastic strain in the workpiece. Several cutting parameters that are often neglected in simplified metal-cutting models are included, such as elastic-plastic material properties of both the workpiece and tool, friction along the tool rake face, and geometry of the cutting edge and workpiece. The model predicts chip geometry, residual stresses in the workpiece, and tool stresses and forces, without any reliance on empirical metal cutting data. The paper demonstrates that use of a chip separation criterion based on effective plastic strain is essential in predicting chip geometry and residual stresses with the finite element method.


2000 ◽  
Vol 123 (1) ◽  
pp. 150-154
Author(s):  
John H. Underwood ◽  
Michael J. Glennon

Laboratory fatigue life results are summarized from several test series of high-strength steel cannon breech closure assemblies pressurized by rapid application of hydraulic oil. The tests were performed to determine safe fatigue lives of high-pressure components at the breech end of the cannon and breech assembly. Careful reanalysis of the fatigue life tests provides data for stress and fatigue life models for breech components, over the following ranges of key parameters: 380–745 MPa cyclic internal pressure; 100–160 mm bore diameter cannon pressure vessels; 1040–1170 MPa yield strength A723 steel; no residual stress, shot peen residual stress, overload residual stress. Modeling of applied and residual stresses at the location of the fatigue failure site is performed by elastic-plastic finite element analysis using ABAQUS and by solid mechanics analysis. Shot peen and overload residual stresses are modeled by superposing typical or calculated residual stress distributions on the applied stresses. Overload residual stresses are obtained directly from the finite element model of the breech, with the breech overload applied to the model in the same way as with actual components. Modeling of the fatigue life of the components is based on the fatigue intensity factor concept of Underwood and Parker, a fracture mechanics description of life that accounts for residual stresses, material yield strength and initial defect size. The fatigue life model describes six test conditions in a stress versus life plot with an R2 correlation of 0.94, and shows significantly lower correlation when known variations in yield strength, stress concentration factor, or residual stress are not included in the model input, thus demonstrating the model sensitivity to these variables.


Author(s):  
A Ktari ◽  
A Abdelkefi ◽  
N Guermazi ◽  
P Malecot ◽  
N Boudeau

During tube hydroforming process, the friction conditions between the tube and the die have a great importance on the material plastic flow and the distribution of residual stresses of the final component. Indeed, a three-dimensional finite element model of a tube hydroforming process in the case of square section die has been performed, using dynamic and static approaches, to study the effect of the friction conditions on both plastic flow and residual stresses induced by the process. First, a comparative study between numerical and experimental results has been carried out to validate the finite element model. After that, various coefficients of friction were considered to study their effect on the thinning phenomenon and the residual stresses distribution. Different points have been retained from this study. The thinning is located in the transition zone cited between the straight wall and the corner zones of hydroformed tube due to the die–tube contact conditions changes during the process. In addition, it is clear that both die–tube friction conditions and the tube bending effects, which occurs respectively in the tube straight wall and corner zones, are the principal causes of the obtained residual stresses distribution along the tube cross-section.


Author(s):  
Michael C. Gibson ◽  
Amer Hameed ◽  
John G. Hetherington

Swaging is one method of autofrettage, a means of pre-stressing high-pressure vessels to increase their fatigue lives and load bearing capacity. Swaging achieves the required deformation through physical interference between an oversized mandrel and the bore diameter of the tube, as it is pushed through the tube. A Finite Element model of the swaging process was developed, in ANSYS, and systematically refined, to investigate the mechanism of deformation and subsequent development of residual stresses. A parametric study was undertaken, of various properties such as mandrel slope angle, parallel section length and friction coefficient. It is observed that the axial stress plays a crucial role in the determination of the residual hoop stress and reverse yielding. The model, and results obtained from it, provides a means of understanding the swaging process and how it responds to different parameters. This understanding, coupled with future improvements to the model, potentially allows the swaging process to be refined, in terms of residual stresses development and mandrel driving force.


Author(s):  
Pablo Vasquez ◽  
Natalia Nun˜o

A personalized 3D model of the proximal femur is reconstructed from medical CT-scan images. The mechanical properties of the cortical and spongious bones are extracted from the medical images. A finite element model of a personalized total hip arthroplasty is developed to investigate the effect of residual stresses due to cement curing in the load transfer during simplified heel strike.


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