A Physically Based Method of Enhancement of Experimental Data Concepts, Formulation and Application to Identification of Residual Stresses

1993 ◽  
pp. 61-70 ◽  
Author(s):  
Wojciech Karmowski ◽  
Janusz Orkisz
Keyword(s):  
Experimental Data ◽  
Residual Stresses ◽  
Physically Based

Ultrasonic Evaluation of Compressive Residual Stress of Surface Treated Metals

2005 ◽  
Vol 490-491 ◽  
pp. 184-189 ◽  
Author(s):  
Farid Belahcene ◽  
Xiaolai Zhou ◽  
Jian Lu
Keyword(s):  
Experimental Data ◽  
Residual Stresses ◽  
Nondestructive Evaluation ◽  
Subsurface Layer ◽  
Surface Mechanical Attrition Treatment ◽  
Shallow Subsurface ◽  
Ultrasonic Evaluation ◽  
Mechanical Attrition ◽  
Machine Parts ◽  
Compressive Residual Stresses

Shot peening is an effective method of improving fatigue performance of machine parts in the industry by producing a thin surface layer of compressive residual stresses that prevents crack initiation and retards crack growth during service. Nondestructive evaluation of the prevailing compressive residual stresses in the shallow subsurface layer is realized by the critically refracted longitudinal (Lcr) waves. This paper presents experimental data obtained on SMAT (surface mechanical attrition treatment) steel alloy S355 sample. Comparative travel-time shows that there are statistically significant differences in treated and untreated specimen. With knowledge of the acoustoelastic constants which are obtained by a test calibration, the experimental data indicates that compressive residual stresses are distributed near subsurface (hundreds of micron). These stress results show that the Lcr technique is efficient for evaluation of residual stresses after the surface treatment.

FE analysis of the effects of process representations on the prediction of residual stresses and chip morphology in the down-milling of Ti6Al4V

2021 ◽  
pp. 1-50
Author(s):  
Nejah Tounsi ◽  
Tahany El-Wardany
Keyword(s):  
Experimental Data ◽  
Residual Stresses ◽  
Orthogonal Cutting ◽  
Chip Thickness ◽  
Chip Morphology ◽  
Milling Process ◽  
Uncut Chip Thickness ◽  
Orthogonal Machining ◽  
Cutting Length ◽  
Sequential Cuts

Abstract Part I of these two-part papers will investigate the effect of three FEM representations of the milling process on the prediction of chip morphology and residual stresses (RS), when down-milling small uncut chips with thickness in the micrometer range and finite cutting edge radius. They are: i) orthogonal cutting with the mean uncut chip thickness t, obtained by averaging the uncut chip thickness over the cutting length, ii) orthogonal cutting with variable t, which characterizes the down-milling process and which is imposed on a flat surface of the final workpiece, and iii) modelling the true kinematics of the down milling process. The appropriate constitutive model is identified through 2D FEM investigation of the effects of selected constitutive equations and failure models on the prediction of RS and chip morphology in the dry orthogonal machining of Ti6Al4V and comparison to experimental measurements. The chip morphology and RS prediction capability of these representations is assessed using the available set of experimental data. Models featuring variable chip thickness have revealed the transition from continuous chip formation to the rubbing mode and have improved the predictions of residual stresses. The use of sequential cuts is necessary to converge toward experimental data.

Determination of the Residual Stresses in Composite Laminate Using the Compliance Method

2005 ◽  
Vol 490-491 ◽  
pp. 533-538 ◽  
Author(s):  
Guillaume Montay ◽  
Olivier Sicot ◽  
X.L. Gong ◽  
Abel Cherouat ◽  
Jian Lu
Keyword(s):  
Experimental Data ◽  
Residual Stresses ◽  
Composite Laminates ◽  
Composite Laminate ◽  
Constant Width ◽  
Strain Gages ◽  
New Methods ◽  
Structure Surface ◽  
Finite Elements Simulation

Residual stresses play an important role on the mechanical behavior of composite laminate. The development of new methods to determine the residual stresses gradient within the laminates is necessary. This article presents the adaptation of the compliance method in the case of composite laminates carbon/epoxy [02/902]s. The incremental drilling of a constant width groove allows for each increment to measure the strains (using strain gages) and displacements (using an optical device) of particularly points of the structure surface. These experimental data are compared with results given by a finite elements simulation. This comparison allows to raise the residual stresses in the composite laminate.

A Novel Modeling Method to Study the Oxide Layer Effect on Metallic Bonding in Cold Gas Dynamic Spray Process

2021 ◽  
Author(s):  
Saeed Rahmati ◽  
Bertrand Jodoin ◽  
R.G.A. Veiga ◽  
A. Zúñiga
Keyword(s):  
Experimental Data ◽  
Oxide Layer ◽  
Spray Process ◽  
Physically Based ◽  
Layer Effect ◽  
Element Approach ◽  
Cold Gas Dynamic Spray ◽  
Gas Dynamic Spray ◽  
Metallic Bonding ◽  
Theory And Experiments

Abstract In this study; a new physically-based finite element approach is proposed to model and predict the superficial oxide layer removal and the occurrence of localized metallic bonding during particle impacts. The process physics; based on explosive welding theory and experiments; and method implementation is presented. Prediction of critical velocity of copper is obtained and compared to experimental data to validate the model. Moreover; the model is also able to show the bonding locations at the interface between particles and substrate. The predicted bonding locations are consistent with experimental data from literature for several metals.

scholarly journals Anisotropic residual stresses in arteries

2019 ◽  
Vol 16 (151) ◽  
pp. 20190029 ◽  
Author(s):  
Taisiya Sigaeva ◽  
Gerhard Sommer ◽  
Gerhard A. Holzapfel ◽  
Elena S. Di Martino
Keyword(s):  
Experimental Data ◽  
Residual Stresses ◽  
Abdominal Aorta ◽  
Strain Energy Function ◽  
Opening Angle ◽  
Link Type ◽  
Residual Deformations ◽  
Angle Method ◽  
The Individual

The paper provides a deepened insight into the role of anisotropy in the analysis of residual stresses in arteries. Residual deformations are modelled following Holzapfel and Ogden (Holzapfel and Ogden 2010, J. R. Soc. Interface 7 , 787–799. ( doi:10.1098/rsif.2009.0357 )), which is based on extensive experimental data on human abdominal aortas (Holzapfel et al. 2007, Ann. Biomed. Eng. 35 , 530–545. ( doi:10.1007/s10439-006-9252-z )) and accounts for both circumferential and axial residual deformations of the individual layers of arteries—intima, media and adventitia. Each layer exhibits distinctive nonlinear and anisotropic mechanical behaviour originating from its unique microstructure; therefore, we use the most general form of strain-energy function (Holzapfel et al. 2015, J. R. Soc. Interface 12 , 20150188. ( doi:10.1098/rsif.2015.0188 )) to derive residual stresses for each layer individually. Finally, the systematic experimental data (Niestrawska et al. 2016, J. R. Soc. Interface 13 , 20160620. ( doi:10.1098/rsif.2016.0620 )) on both mechanical and structural properties of the different layers of the human abdominal aorta facilitate our discussion on (i) the importance of anisotropy in modelling residual stresses; (ii) the variability of residual stresses within the same class of tissue, the abdominal aorta; (iii) the limitations of conventional opening angle method to account for complex residual deformations; and (iv) the effect of residual stresses on the loaded configuration of the aorta mimicking in vivo conditions.

Analytical evaluation of thermally induced residual stresses in ground components

2003 ◽  
Vol 217 (5) ◽  
pp. 471-482 ◽  
Author(s):  
D G Walsh ◽  
A A Torrance ◽  
J Tiberg
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Critical Temperature ◽  
Yield Strength ◽  
Residual Stresses ◽  
Material Properties ◽  
Analytical Evaluation ◽  
Simple Method ◽  
Thermally Induced

Although thermally induced tensile residual stresses have been known to occur in ground components, it has not been possible to predict the critical temperature at which these stresses begin to manifest themselves in the workpiece. In this paper, a model of the formation of thermally induced tensile residual stresses is proposed and a simple method of calculating the critical temperature above which tensile residual stresses occur is developed. The analysis makes use of dimensional methods to characterize the critical temperature. In addition, a formula characterizing the yield strength as a function of temperature was developed. The model was then validated using finite element techniques and some experimental data. The analysis reveals that it is possible to determine the critical temperature above which tensile residual stresses will be manifested based on readily available material properties. A case study illustrates the application of the technique.

Simulation of Surface Crack Initiation Induced by Slip Localization and Point Defect Kinetics

2014 ◽  
Vol 891-892 ◽  
pp. 542-548 ◽  
Author(s):  
Maxime Sauzay ◽  
Jia Liu
Keyword(s):  
Experimental Data ◽  
Crack Initiation ◽  
Surface Crack ◽  
Strong Relationship ◽  
Recent Experimental Data ◽  
Slip Bands ◽  
Persistent Slip Bands ◽  
Microcrack Initiation ◽  
Physically Based ◽  
Surface Crack Initiation

Crack initiation along surface persistent slip bands (PSBs) has been widely observed and modelled. Nevertheless, from our knowledge, no physically-based fracture modelling has been proposed and validated with respect to the numerous recent experimental data showing the strong relationship between extrusion and microcrack initiation.

scholarly journals The method of reconstruction of residual stresses and plastic deformations in thin-walled pipelines in the delivery state and after bilateral vibro-shock surface hardening with a shot

2020 ◽  
pp. 123-133
Author(s):  
V. P Radchenko ◽  
V. Ph Pavlov ◽  
T. I Berbasova ◽  
M. N Saushkin
Keyword(s):  
Experimental Data ◽  
Plastic Deformation ◽  
Residual Stresses ◽  
Strain Tensor ◽  
Anisotropy Parameter ◽  
Surface Plastic ◽  
Phenomenological Method ◽  
Stress Strain ◽  
Plastic Deformations ◽  
Thin Walled

We suggest the phenomenological method of reconstructing the fields of residual stresses and plastic deformations in thin-walled cylindrical tubes made of Х18N10Т steel in the delivery state and after a simultaneous bilateral surface plastic hardening by the vibration-shot blasting of the surface with beads on a special vibrating stand. A cylindrical container filled with three-millimeter beads was attached to it. The tubes were 50 % filled with one-millimeter beads, and they were placed inside the container. The axis of the tube and the container coincided. The space between the tube and the container was 80 % filled with beads. The vibrational frequency of the stand was 18.5 KHz, the hardening time was 20 minutes. The tube in the container was rotated to ensure uniform hardening. We determined the experimental values of residual stresses σθ and σ z in the surface layers using the method of rings and strips with the procedure of the layer-by-layer electrochemical picking of the hardened layers. For this purpose, the experimentally measured values of the beam-strip deflection and the angular opening of the cut ring (changing the diameter) were used. The hardening anisotropy parameter which relates the axial and circumferential components of plastic deformation was introduced into the mathematical model. In solving the stated problems the hypotheses of plastic incompressibility of the material, the absence of secondary plastic deformations of the material in the compression region of the surface layer, as well as the hypothesis of flat sections and straight radii were used. We described the method aimed at solving this type of boundary value problems of reconstructing stress-strain states, which makes it possible to determine the missing component σ r and all the components of the tensor of residual plastic deformations (off-diagonal components of the tensors of stresses and deformations were not considered). The method of reconstructing the stress-strain state is universal, because it has shown its operability both in determining the technological fields of residual stresses, as well as the irreversible strains in the samples in the delivered state after mechanical operations, and after bilateral surface plastic deformation. The adequacy of the calculated data was verified, which was obtained using the phenomenological method of reconstructing the stress and strain fields of the experimental data for the samples in the delivery state and after hardening. The correspondence of the calculated and experimental data was matched. The numerical values are given for the anisotropy parameter connecting the circumferential and axial irreversible strains, for samples, in the delivery state, its numerical value is 0.1, and, for the hardened samples, it is 4.2. This indicates a significant anisotropy of the distribution of the axial and circumferential components of the residual strain tensor. It has been established that the compressive residual stresses are observed in the delivery state in the region adjacent to the inner surface, and the tensile stresses are observed in the layer on the outer surface. Only compressive stresses are observed in both regions after hardening, which significantly exceed in module similar stresses for the samples in the delivery state. The main results are illustrated by the tabular data and the corresponding diagrams of the distribution of residual stresses along the depth of the hardened layer.

Residual stresses during surface cleaning with elastic abrasive wheels

2020 ◽  
pp. 54-61
Author(s):  
YU.V. Dimov ◽  
D.B. Podashev
Keyword(s):  
Experimental Data ◽  
Residual Stresses ◽  
Cutting Force ◽  
Temperature Effects ◽  
Cutting Speed ◽  
Surface Cleaning ◽  
Abrasive Wheel ◽  
Decisive Influence ◽  
Definition Of

An analytical definition of residual stresses during processing with elastic abrasive wheels (EAW) is proposed. It is established, that the rigidity of the EAW determines the decisive influence of force or temperature effects on residual stresses. The adequacy of the analytical definition is confirmed by experimental data. Keywords elastic abrasive wheel, residual stresses, cutting speed, deformation, cutting force, temperature. [email protected]

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