scholarly journals Efficiency of Plasticity Correction in the Hole-Drilling Residual Stress Measurement

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3396
Author(s):  
Tomáš Návrat ◽  
Dávid Halabuk ◽  
Petr Vosynek
Keyword(s):  
Residual Stress ◽  
Stress State ◽  
Uniaxial Tension ◽  
Relative Error ◽  
Computational Simulation ◽  
Equivalent Stress ◽  
Biaxial Stress ◽  
Hole Drilling ◽  
Plane Shear ◽  
Plasticity Effect

This paper focuses on the analysis of the plasticity effect in the measurement of the residual stress by the hole-drilling method. Relaxed strains were evaluated by the computational simulation of the hole-drilling experiment using the finite element method. Errors induced by the yielding were estimated for uniaxial tension, plane shear stress state and equi-biaxial stress state at various magnitudes of residual stress uniformly distributed along the depth. The correction of the plasticity effect in the evaluation of residual stress was realized according to the method proposed by authors from the University in Pisa, which was coded in MATLAB. Results obtained from the MATLAB script were compared to the original input data of the hole-drilling simulation and discussed. The analyses suggested that the plasticity effect is negligible at the ratio of applied equivalent stress to yield stress, being 0.6, and that the correction of the plasticity effect is very successful at the previous ratio, being 0.9. Failing to comply with the condition of the strain gauge rosette orientation according to the principal stresses directions causes an increase in the relative error of corrected stresses only for the case of uniaxial tension. It affects the relative error negligibly for the plane shear and equi-biaxial stress states.

Characteristics of Residual Stress by Water-Jet Peening

2013 ◽  
Vol 768-769 ◽  
pp. 564-571 ◽  
Author(s):  
Kenji Suzuki ◽  
Takahisa Shobu ◽  
Ayumi Shiro
Keyword(s):  
Residual Stress ◽  
Stress State ◽  
Water Jet ◽  
Biaxial Stress ◽  
X Rays ◽  
Lattice Plane ◽  
Scanning Method ◽  
Depth Direction ◽  
Biaxial Stress State ◽  
Specimen Material

The specimen material was austenitic stainless steel, SUS316L. The residual stress was induced by water-jet peening. The residual stress was measured using the 311 diffraction with conventional X-rays. The measured residual stress showed the equi-biaxial stress state. To investigate thermal stability of the residual stress, the specimen was aged thermally at 773 K in air to 1000 h. The residual stress kept the equi-biaxial stress state against the thermal aging. Lattice plane dependency of the residual stress induced by water-jet peening was evaluated using hard synchrotron X-rays. The residual stress measured by the soft lattice plane showed the equi-biaxial stress state, but the residual stress measured by the hard lattice plane did not. In addition, the distributions of the residual stress in the depth direction were measured using a strain scanning method with hard synchrotron X-rays and neutrons.

Modelling shattered rim cracking in railroad wheels

2011 ◽  
Vol 225 (6) ◽  
pp. 593-604
Author(s):  
V Sura ◽  
S Mahadevan
Keyword(s):  
Residual Stress ◽  
Stress Intensity Factor ◽  
Finite Element ◽  
Stress Intensity ◽  
Stress State ◽  
Intensity Factor ◽  
Residual Stresses ◽  
Equivalent Stress ◽  
Crack Tip ◽  
Residual Stress State

Shattered rim cracking, propagation of a subsurface crack parallel to the tread surface, is one of the dominant railroad wheel failure types observed in North America. This crack initiation and propagation life depends on several factors, such as wheel rim thickness, wheel load, residual stresses in the rim, and the size and location of material defects in the rim. This article investigates the effect of the above-mentioned parameters on shattered rim cracking, using finite element analysis and fracture mechanics. This cracking is modelled using a three-dimensional, multiresolution, elastic–plastic finite element model of a railroad wheel. Material defects are modelled as mathematically sharp cracks. Rolling contact loading is simulated by applying the wheel load on the tread surface over a Hertzian contact area. The equivalent stress intensity factor ranges at the subsurface crack tips are estimated using uni-modal stress intensity factors obtained from the finite element analysis and a mixed-mode crack growth model. The residual stress and wheel wear effects are also included in modelling shattered rim cracking. The analysis results show that the sensitive depth below the tread surface for shattered rim cracking ranges from 19.05 to 22.23 mm, which is in good agreement with field observations. The relationship of the equivalent stress intensity factor (Δ K eq) at the crack tip to the load magnitude is observed to be approximately linear. The analysis results show that the equivalent stress intensity factor (Δ K eq) at the crack tip depends significantly on the residual stress state in the wheel. Consideration of as-manufactured residual stresses decreases the Δ K eq at the crack tip by about 40 per cent compared to that of no residual stress state, whereas consideration of service-induced residual stresses increases the Δ K eq at the crack tip by about 50 per cent compared to that of as-manufactured residual stress state. In summary, the methodology developed in this article can help to predict whether a shattered rim crack will propagate for a given set of parameters, such as load magnitude, rim thickness, crack size, crack location, and residual stress state.

scholarly journals The Application of Digital Image Correlation for Measuring Residual Stress by Incremental Hole Drilling

2008 ◽  
Vol 13-14 ◽  
pp. 65-73 ◽  
Author(s):  
Jerry D. Lord ◽  
David Penn ◽  
P. Whitehead
Keyword(s):  
Residual Stress ◽  
Digital Image Correlation ◽  
Digital Image ◽  
Strain Gauge ◽  
Biaxial Stress ◽  
Image Correlation ◽  
Hole Drilling ◽  
Validation Data ◽  
Strain Fields ◽  
Incremental Hole Drilling

The measurement of residual stress using the incremental hole drilling is well established, but the main limitations with the conventional strain gauge approach are the requirements for surface preparation, the need for accurate alignment and drilling, the restricted range of hole geometries commensurate with the specific gauge designs, and the limited range of strain data averaged over the footprint of the strain gauge grid. Recent attempts to extend the method have seen the application of full field optical techniques such as electronic speckle pattern interferometry and holographic interferometry for measuring the strain fields around the hole, but these methods are sensitive to vibration and this limits their practical use to controlled laboratory environments. There are significant potential benefits therefore of using a more robust technique based on Digital Image Correlation (DIC), and work is presented in this study on the development of the method for measuring surface displacements and strain fields generated during incremental hole drilling. Some of the practical issues associated with the technique development, including the optimization of applied patterns, the development of the optical system and integration with current hole drilling equipment are discussed, and although measurements are only presented for a single load case - the equi-biaxial stress state introduced during shot peening - the novel aspect of this work is the integration of DIC measurements with incremental drilling and an application of the Integral Method analysis to measure the variation of residual stress with depth. Validation data comparing results from conventional strain gauge data and FE models is also presented.

The Influence of Different Stress States on 16MnR Deformation Capacity

2013 ◽  
Vol 716 ◽  
pp. 590-594
Author(s):  
Shi Lei Zhao ◽  
Yi Liang Zhang ◽  
Gong Feng Jiang
Keyword(s):  
Plastic Deformation ◽  
Stress State ◽  
Equivalent Stress ◽  
Great Influence ◽  
Equivalent Strain ◽  
Complex Stress State ◽  
Biaxial Stress ◽  
Deformation Capacity ◽  
Engineering Structures ◽  
Stress States

16MnR is the typical material of pressure equipment which worked under complex stress state in engineering application. In order to be close to the actual combined tension-shearing stress state and explore the relationship of deformation capacity and different stress state, many groups of combined tension-torsion tests on 16MnR specimens were designed and the equivalent stress-strain relation under different stress state was obtained. The concept of stress triaxiaty (TS value) was cited to characterize the different stress state and the result showed different stress states have a great influence on the material plastic deformation capacity, TS value turns larger, the plastic deformation weakened; 16MnR has a strongest plastic deformation capacity in pure torsion; the level of tensile stress had no significant effect on the maximum stress in the biaxial stress state, but has a significant inverse relationship with the maximum equivalent strain .At last, the mathematical relationship between maximum equivalent-strain and stress triaxiaty could be found. If the stress state of one point in the engineering structures is certain, the maximum equivalent-strain can be estimated.

The Influence of Multiaxial Stress Relaxation on Component Creep Damage Accumulation

2020 ◽  
Vol 143 (3) ◽  
Author(s):  
Nayden Matev ◽  
Robert A. Ainsworth ◽  
Meini Su ◽  
Mark Stevens ◽  
Alan Jappy
Keyword(s):  
Stress State ◽  
Stress Drop ◽  
Damage Accumulation ◽  
Stress Ratio ◽  
Equivalent Stress ◽  
Creep Damage ◽  
Biaxial Stress ◽  
Multiaxial Stress ◽  
Multiaxial Stress State

Abstract Unless inelastic analysis is used, high temperature codes base creep relaxation on the start-of-dwell equivalent stress, which relaxes according to a uniaxial creep law. Elastic follow-up is also included. This approach only evaluates equivalent stress and creep strain rate and the multiaxial stress state is assumed to remain at its initial value as the stress relaxes. Codes suggest that the stress drop is limited to a fraction (typically 20%) of the initial equivalent stress to ensure this assumption does not introduce significant inaccuracies. This article provides a numerical examination of creep relaxation of a cruciform plate subjected to displacement-controlled biaxial loading, with the aim to provide clarification of any required constraint on stress drop. The initial biaxial stress ratio, the plate geometry and the power in a power–law creep model are varied, leading to variations in the elastic follow-up describing the creep relaxation. The biaxial stress ratio is generally found to change with relaxation and a multiaxial ductility approach is used to evaluate the associated creep damage accumulation. This is compared with the damage estimated assuming relaxation is controlled by the equivalent stress with no change in multiaxial stress state. For biaxial plane stress with one principal stress initially being compressive and one tensile, it is found that significant equivalent stress drops (about 40% of the initial stress) can be allowed without the simplified equivalent stress approach becoming inaccurate. More care is required for tensile–tensile stress biaxiality where multiaxial stress changes depend on the initial stress biaxiality and the degree of elastic follow-up. The results will be used to propose improved guidance for simplified inelastic calculations.

HRSG-Pipeline Weld Residual-Stress Measurement to Assess Influence Over Creep-Analysis Results From Italian Code, American Standard

2019 ◽  
Author(s):  
Ottaviano Grisolia ◽  
Lorenzo Scano ◽  
Francesco Piccini ◽  
Antonietta Lo Conte ◽  
Massimiliano De Agostinis ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stress Measurement ◽  
Numerical Models ◽  
Equivalent Stress ◽  
Welding Process ◽  
Diffraction Method ◽  
Hole Drilling ◽  
Creep Analysis ◽  
Maximum Residual Stress ◽  
American Standard

Abstract Previous study carried out residual stress characterization for the welds of the high-temperature-section (superheater / reheater) lower headers of the bottom-supported heat-recovery steam generator (HRSG). Modeling the gas-tungsten arc, manual welding process considered only weld-lay for the ASTM A 335-Grade P22 finned-tube angle joint to the cylinder. Present study aims at indirectly assessing findings of previous analysis measuring maximum residual stress on the joint’s exservice material. To achieve that a tee similar to the previous was not available: for both experimental and numerical analyses present study considers a P22 circumferential “V”-groove butt joint on HRSG pipeline section, creep-operated for the same period and temperature as the previous case. In the experimental activity X-ray diffraction method (or alternatively, hole-drilling strain gage one) applies as close as possible to the weld, being residual stress maximum at the fusion boundary. Thermal analysis for the previous case also showed it keeps nearly constant during weld cooling, relaxing most during creep: after 200,000 hours of operation, welding-process simulation predicted a maximum residual stress of 70 MPa; tee-joint creep-analysis found out a maximum equivalent stress of 91 MPa. As for the sample withdrawal, dimensions should be sufficient to avoid any interference with measurement area. The experimental procedures should comply with the European standard EN 15305 on the matter (the American standard ASTM E 837 for the alternate method). Comparison of analysis results for the two cases, confirms tendencies previously found out in creep-behavior, though different equivalent stress contributions. Comparison of predicted and observed residual stress values should allow for validation of numerical models used in both welding process and stress analysis.

Experimental Verification of the Hole Drilling Plasticity Effect Correction

2011 ◽  
Vol 681 ◽  
pp. 151-158 ◽  
Author(s):  
M. Beghini ◽  
Ciro Santus ◽  
Emilio Valentini ◽  
A. Benincasa
Keyword(s):  
Residual Stress ◽  
Stress Concentration ◽  
Numerical Procedure ◽  
Hole Drilling ◽  
Stressed Volume ◽  
Hole Drilling Method ◽  
Plasticity Effect ◽  
Drilling Method ◽  
Stress Components ◽  
Perturbation Effect

The Hole Drilling Method introduces a hole in a (residual) stressed volume of material, typically a metal, then a stress concentration follows. A portion of the volume near the hole can experience a stress concentration and then plasticity. The relaxed strains measured by the rosette strain gage grids are then affected by this plasticity volume especially when the residual stress is quite large with respect to the material yield stress. This is the so called Hole Drilling Plasticity Effect. The authors recently proposed a numerical procedure to correct this perturbation effect and retrieve more accurate residual stress components values. An experimental validation of this correction procedure is reported in the paper.

Fatigue Life Properties of Stainless Steels in Wide Ranged Biaxial Stress State

2019 ◽  
Vol 795 ◽  
pp. 60-65
Author(s):  
Shunsuke Saito ◽  
Fumio Ogawa ◽  
Takamoto Itoh
Keyword(s):  
Fatigue Life ◽  
Stress State ◽  
Stainless Steels ◽  
Equivalent Stress ◽  
Fatigue Tests ◽  
Multiaxial Fatigue ◽  
Biaxial Stress ◽  
Loading Path ◽  
Inner Pressure ◽  
Biaxial Stress State

Multiaxial fatigue tests consisting of push-pull loading and cyclic inner pressure were carried out using hollow cylinder specimens of type 430 stainless and type 316 stainless steels at room temperature. 7 types of cyclic loading paths were employed by combining axial and hoop stresses: a Pull, an Inner-pressure, a Push-pull, an Equi-biaxial, a Square-shape, a LT-shape and a LC-shape. Fatigue lives vary depending on the loading path when those were evaluated by the maximum Mises’ equivalent stress on inner surface of the specimen. The fatigue lives of both the steels showed a similar tendency although some Pull tests take longer fatigue life when cracks initiated from inside surface of the specimen. This study investigated the crack initiation and propagation behaviors as well as the initiation of oil leakage to prove the behavior and discusses life evaluation for two steels under wide ranged biaxial stress state, too.

scholarly journals The effect of third principal stress in the measurement of residual stresses by hole-drilling method

2018 ◽  
Vol 237 ◽  
pp. 01012
Author(s):  
David Halabuk ◽  
Tomas Navrat
Keyword(s):  
Residual Stress ◽  
Stress State ◽  
Residual Stresses ◽  
Triaxial Stress ◽  
Perpendicular Direction ◽  
Hole Drilling ◽  
Triaxial Stress State ◽  
Hole Drilling Method ◽  
Plane Parallel ◽  
Drilling Method

One of the most popular and widely used technique for measuring residual stresses is the hole-drilling method. By this method, it is possible to evaluate only biaxial residual stresses located in plane parallel to the surface, but some processes produce a triaxial stress state. For this reason, the evaluation of triaxial stress state by the method used for biaxial state was assessed in this paper. A hole-drilling experiment was simulated by the finite element method for two different stress states. The first stress state considered constant residual stresses in all directions. The second one considered constant residual stresses in a plane parallel to the surface and the residual stress in a direction perpendicular to the surface was equal to zero on the surface and increased with depth. Both states were simulated for various ratios of stress in a direction perpendicular to the stresses in plane. The obtained results show that residual stress in a perpendicular direction affects the evaluation of residual stresses in plane. If the residual stress in the perpendicular direction is high compared to stresses in plane, the error produced by the evaluation of triaxial stress state by the method for biaxial stress state can also be high. 1 Introduction

scholarly journals Identification of Residual Stress Phenomena Based on the Hole Drilling Method in Explosively Welded Steel-Titanium Composite

2014 ◽  
Vol 59 (3) ◽  
pp. 1119-1123 ◽  
Author(s):  
A. Karolczuk ◽  
M. Kowalski ◽  
K. Kluger ◽  
F. Żok
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Stress State ◽  
Welding Process ◽  
Hole Drilling ◽  
Titanium Layer ◽  
Hole Drilling Method ◽  
Bimetallic Composite ◽  
Residual Stress State ◽  
Drilling Method

Abstract The hole drilling method was used to determine residual stresses in bimetallic composite manufactured by explosive welding process. The analyzed bimetal consist of titanium Grade 1 (6mm) and S355J2+N steel (40mm). The aim of the paper is to establish the influence of the heat treatment on residual stress state in titanium layer. Residual stress calculations were performed according to standards developed by strain gauge manufacturer (TML) and ASTM standards. The main conclusion is the heat treatment considerably changes the residual stress state in titanium layer from tensile stress state (no heat treatment) to compression stress state (after the heat treatment).

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