Analysis of a Notched Four-Point Bending Sample Containing Various Residual Stresses

2009 ◽  
pp. 65-65-17
Author(s):  
JA Kapp ◽  
A Stacey
Keyword(s):  
Residual Stresses ◽  
Four Point Bending

scholarly journals Additive Manufactured 316L Stainless-Steel Samples: Microstructure, Residual Stress and Corrosion Characteristics after Post-Processing

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 182
Author(s):  
Suvi Santa-aho ◽  
Mika Kiviluoma ◽  
Tuomas Jokiaho ◽  
Tejas Gundgire ◽  
Mari Honkanen ◽  
...  
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Sample Surface ◽  
Post Processing ◽  
Magnesium Chloride Solution ◽  
Manufacturing Method ◽  
Four Point Bending ◽  
Traditional Manufacturing ◽  
Processing Steps ◽  
Compressive Residual Stresses

Additive manufacturing (AM) is a relatively new manufacturing method that can produce complex geometries and optimized shapes with less process steps. In addition to distinct microstructural features, residual stresses and their formation are also inherent to AM components. AM components require several post-processing steps before they are ready for use. To change the traditional manufacturing method to AM, comprehensive characterization is needed to verify the suitability of AM components. On very demanding corrosion atmospheres, the question is does AM lower or eliminate the risk of stress corrosion cracking (SCC) compared to welded 316L components? This work concentrates on post-processing and its influence on the microstructure and surface and subsurface residual stresses. The shot peening (SP) post-processing levelled out the residual stress differences, producing compressive residual stresses of more than −400 MPa in the AM samples and the effect exceeded an over 100 µm layer below the surface. Post-processing caused grain refinement and low-angle boundary formation on the sample surface layer and silicon carbide (SiC) residue adhesion, which should be taken into account when using the components. Immersion tests with four-point-bending in the heated 80 °C magnesium chloride solution for SCC showed no difference between AM and reference samples even after a 674 h immersion.

Characterization of Zirconia-Based Ceramics After Microgrinding

2019 ◽  
Vol 7 (2) ◽  
Author(s):  
Pablo Fook ◽  
Oltmann Riemer
Keyword(s):  
Surface Roughness ◽  
Flexural Strength ◽  
Residual Stresses ◽  
Machining Parameters ◽  
X Ray Diffraction ◽  
Four Point Bending ◽  
Ductile Mode ◽  
Recent Developments ◽  
Vibration Assistance ◽  
Diamond Grain

Despite the recent developments of ductile mode machining, microgrinding of bioceramics can cause an insufficient surface and subsurface integrity due to the inherent hardness and brittleness of such materials. This work aims to determine the influence of a two-step grinding operation on zirconia-based ceramics. In this regard, zirconia (ZrO2) and zirconia toughened alumina (ZTA) specimens are ground with ultrasonic vibration assistance within a variation of the machining parameters using two grinding steps and different diamond grain sizes of the tools in each of the machining procedure. White light interferometry, scanning electron microscope, X-ray diffraction (XRD), and four-point bending tests are performed to evaluate surface roughness, microstructure, residual stresses, and flexural strength, respectively. The strategy applied suggests that the finished parts are suitable for certain biomedical uses like dental implants due to their optimum surface roughness. Moreover, concerning the mechanical properties, an increase of the flexural strength and compressive residual stresses of ground ZrO2 and ZTA workpieces were observed in comparison to the as-received specimens. These results, as well as the methodology proposed to investigate the surface integrity of the ground workpieces, are helpful to understand the bioceramic materials response under microgrinding conditions and to set further machining investigations.

scholarly journals Numerical characterization of residual stresses in a four-point-bending experiment of textured duplex stainless steel

2021 ◽  
Author(s):  
S. F. Maassen ◽  
H. Erdle ◽  
S. Pulvermacher ◽  
D. Brands ◽  
T. Böhlke ◽  
...  
Keyword(s):  
Residual Stresses ◽  
Volume Fraction ◽  
Mean Field Theory ◽  
Mean Field ◽  
Three Dimensional ◽  
Bending Test ◽  
Element Analysis ◽  
Austenitic Phase ◽  
Four Point Bending ◽  
Taylor Approximation

AbstractThe resulting shapes in production processes of metal components are strongly influenced by deformation induced residual stresses. Dual-phase steels are commonly used for industrial application of, e.g., forged or deep-drawn structural parts. This is due to their ability to handle high plastic deformations, while retaining desired stiffness for the products. In order to influence the resulting shape as well as component characteristics positively it is important to predict the distribution of phase-specific residual stresses which occur on the microscale of the material. In this contribution a comparative study is presented, where two approaches for the numerical simulation of residual stresses are applied. On the one hand a numerically efficient mean field theory is used to estimate on the grain level the total strain, the plastic strains and the eigenstrains based on macroscopic stress, strain and stiffness data. An alternative ansatz relies on a Taylor approximation for the grain level strains. Both approaches are applied to the corrosion-resistant duplex steel X2CrNiMoN22-5-3 (1.4462), which consists of a ferritic and an austenitic phase with the same volume fraction. Mean field and Taylor approximation strategies are implemented for usage in three dimensional solid finite element analysis and a geometrically exact Euler–Bernoulli beam for the simulation of a four-point-bending test. The predicted residual stresses are compared to experimental data from bending experiments for the phase-specific residual stresses/strains which have been determined by neutron diffraction over the bending height of the specimen.

Neutron diffraction analysis of the residual stress distribution in a bent bar

2000 ◽  
Vol 35 (4) ◽  
pp. 235-246 ◽  
Author(s):  
A. N Ezeilo ◽  
G. A Webster
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Neutron Diffraction ◽  
Residual Stresses ◽  
Residual Stress Distribution ◽  
Four Point Bending ◽  
Refinement Method ◽  
Nickel Based Alloy ◽  
Neutron Diffraction Technique ◽  
Profile Refinement

A well-characterized residual stress distribution resulting from four-point bending has been analysed using the neutron diffraction technique. Residual stresses were obtained from the strains measured at discrete positions through the bent bar on the (111) and (311) crystal planes of a nickel-based alloy using the appropriate diffraction elastic constants. In addition a profile refinement method was used to determine the residual stresses from average strains from all the diffraction peaks in the spectrum. The measured residual stress profiles have also been compared with strain gauge data and with analytical and finite element predictions. It has been established that the profile refinement approach gives stresses which most closely match those obtained by the non-diffraction techniques.

ADIMEW Test: Assessment of a Cracked Dissimilar Metal Weld Assembly

2004 ◽  
Author(s):  
John B. Wintle ◽  
Bridget Hayes ◽  
Martin R. Goldthorpe
Keyword(s):  
Residual Stresses ◽  
Material Properties ◽  
Nuclear Power ◽  
Large Scale ◽  
Research Programme ◽  
Element Analysis ◽  
Dissimilar Metal ◽  
Four Point Bending ◽  
Dissimilar Metal Weld ◽  
Metal Weld

ADIMEW (Assessment of Aged Piping Dissimilar Metal Weld Integrity) was a three-year collaborative research programme carried out under the EC 5th Framework Programme. The objective of the study was to advance the understanding of the behaviour and safety assessment of defects in dissimilar metal welds between pipes representative of those found in nuclear power plant. ADIMEW studied and compared different methods for predicting the behaviour of defects located near the fusion boundaries of dissimilar metal welds typically used to join sections of austentic and ferritic piping operating at high temperature. Assessment of such defects is complicated by issues that include: severe mis-match of yield strength of the constituent parent and weld metals, strong gradients of material properties, the presence of welding residual stresses and mixed mode loading of the defect. The study includes the measurement of material properties and residual stresses, predictive engineering analysis and validation by means of a large-scale test. The particular component studies was a 453mm diameter pipe that joins a section of type A508 Class 3 ferritic pipe to a section of type 316L austentic pipe by means of a type 308 austentic weld with type 308/309L buttering laid on the ferritic pipe. A circumferential, surface-breaking defect was cut using electro discharge machining into the 308L/309L weld buttering layer parallel to the fusion line. The test pipe was subjected to four-point bending to promote ductile tearing of the defect. This paper presents the results of TWI contributions to ADIMEW including: fracture toughness testing, residual stress measurements and assessments of the ADIMEW test using elastic-plastic, cracked body, finite element analysis.

Method to evaluate residual stresses in the laser cutting process

2002 ◽  
Vol 12 (1) ◽  
pp. 27-41 ◽  
Author(s):  
Y. Zamachtchikov ◽  
F. Breaban ◽  
P. Vantomme ◽  
A. Deffontaine
Keyword(s):  
Residual Stresses ◽  
Laser Cutting ◽  
Cutting Process
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