Influence of Cooling Intensity on Residual Stress State of TIG Dressing Zone for T-Joint Welded Toe

2011 ◽  
Vol 148-149 ◽  
pp. 1289-1294 ◽  
Author(s):  
Kun Zhou ◽  
Chun Yuan Shi ◽  
Cheng Jin
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Stress State ◽  
Residual Stresses ◽  
Residual Stress Distribution ◽  
Residual Stress State ◽  
Cooling Intensity ◽  
Stress Layer ◽  
Spray Treatment

Using finite element method, the residual stress distribution of the TIG dressed welded toe followed by spray treatment with different cooling intensity was calculated. And the residual stresses of welded toe were also measured by using the blind-hole method. The results indicate that with the increase of cooling intensity, the longitudinal residual stresses in welded toe are gradually transited from tensile residual stresses to compressive ones, and there is no significant change for transverse residual stresses, and the depth of compressive stress layer increases at the welded toe region.

Influence of Initial Temperature of Chilling Treatment on Residual Stress State of TIG Dressing Zone for T-Joint Welded Toe

2012 ◽  
Vol 268-270 ◽  
pp. 529-533
Author(s):  
Chun Yuan Shi ◽  
Ping Zhu ◽  
Kun Zhou
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Aluminum Alloy ◽  
Residual Stresses ◽  
Initial Temperature ◽  
Residual Stress Distribution ◽  
Residual Stress State ◽  
Significant Change ◽  
Chilling Treatment

Using finite element method, the residual stress distribution of TIG dressed welded toe followed by chilling treatment with different temperature of steel and aluminum alloy T-joint was calculated. And the residual stresses of welded toe were also measured by using the blind-hole method. The results indicate that with the increase of initial temperature of chilling treatment, the longitudinal residual stresses in welded toe of steel joint are gradually transited from tensile residual stresses to compressive ones, and there is no significant change for transverse residual stresses; and the longitudinal residual stresses in welded toe of aluminum alloy joint are compressive stress and gradually increased, no significant change for transverse residual stresses.

Residual Stresses in Self-Curing Bone Cement During Hip Arthroplasty

2003 ◽  
Author(s):  
Chaodi Li ◽  
Ying Wang ◽  
James J. Mason
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Hip Arthroplasty ◽  
Experimental Tests ◽  
Cement Mantle ◽  
Joint Arthroplasty ◽  
Residual Stress Distribution ◽  
Bone Cements

Bone cements are widely used to fix prostheses into bones for joint arthroplasty. During cement curing in total hip arthroplasty, residual stresses are introduced in the cement mantle. A finite element method was developed to predict such residual stress built-up. The effects of curing history on the residual stress distribution were investigated. Results showed that the predictions of the residual stresses agreed with the experimental tests very well. The residual stress build-up was shown to depend on the curing history. By preheating the prosthesis stem prior to implantation, a desired low level residual stress at the critical interface was obtained.

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.

About Residual Stress State of Castings: The Case of HPDC Parts and Possible Advantages through Semi-Solid Processes

2022 ◽  
Vol 327 ◽  
pp. 272-278
Author(s):  
Elisa Fracchia ◽  
Federico Simone Gobber ◽  
Claudio Mus ◽  
Yuji Kobayashi ◽  
Mario Rosso
Keyword(s):  
Residual Stress ◽  
Stress State ◽  
Residual Stresses ◽  
Casting Process ◽  
Ray Method ◽  
Premature Failure ◽  
Thin Walls ◽  
Residual Stress State ◽  
Semi Solid ◽  
Pressure Die Casting

Nowadays, one of the most crucial focus in the aluminium-foundry sector is the production of high-quality castings. Mainly, High-Pressure Die Casting (HPDC) is broadly adopted, since by this process is possible to realize aluminium castings with thin walls and high specific mechanical properties. On the other hand, this casting process may cause tensile states into the castings, namely residual stresses. Residual stresses may strongly affect the life of the product causing premature failure of the casting. Various methods can assess these tensile states, but the non-destructive X-Ray method is the most commonly adopted. Namely, in this work, the residual stress analysis has been performed through Sinto-Pulstec μ-X360s. Detailed measurements have been done on powertrain components realized in aluminium alloy EN AC 46000 through HPDC processes to understand and prevent dangerous residual stress state into the aluminium castings. Furthermore, a comparison with stresses induced by Rheocasting processes is underway. In fact, it is well known that Semi-Solid metal forming combines the advantages of casting and forging, solving safety and environmental problems and possibly even the residual stress state can be positively affected.

Study of the Residual Stresses Variation into the Sandwich Structure Subjected to Thermomechanical Loading

2018 ◽  
Vol 279 ◽  
pp. 113-118
Author(s):  
Khalid Messaoudi ◽  
Farida Bouafia ◽  
Fethi Benkhenafou ◽  
Lyes Douadji ◽  
Wei Wei Du
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stress State ◽  
Residual Stresses ◽  
Mechanical Loading ◽  
Sandwich Structure ◽  
Thermomechanical Loading ◽  
Metal Interface ◽  
Risk Of Rupture ◽  
Different Types

The assembly of different types of materials like metals and ceramics forms a structure called sandwich structure, which need advanced techniques to joint it together like the thermo compression. However, the rise of residual stress caused by the discontinuity of nature of this type of sandwich material, like incompatibility of the characteristics, which creates a risk of rupture of the structure and limited the using range of these types of materials. In this paper, we study the bonding of ceramic and metal and we will focus on the role played by the ceramic element in the stress state of ceramic/ metal interface and the stresses evaluation by Finite Element when the structure is subjected to thermo-Mechanical loading.

Determination of the Residual Stress State of High-Pressure Nozzles During Diamond Smoothing

2020 ◽  
pp. 3-11
Author(s):  
S.A. Zaides ◽  
A.N. Mashukov
Keyword(s):  
Finite Element ◽  
High Pressure ◽  
Stress State ◽  
Residual Stresses ◽  
Element Model ◽  
Depth Of Penetration ◽  
Residual Stress State ◽  
Hardening Treatment ◽  
Cylindrical Parts ◽  
Smoothing Process

The paper presents the results of a study that examines modelling of the polishing and hardening treatment of axisymmetric cylindrical parts such as high-pressure fittings with metal seals on the pipe and the rod. A finite element model of the diamond smoothing process was developed, which allowed one to determine the stress state in the deformation zone depending on the feed rate, tool deflection angle, pressing force, and depth of penetration into the material of the part. The analysis of the modelling results helped to identify a range of optimal modes for diamond smoothing. By using finite element modelling in ANSYS Workbench Mechanical it was possible to test those smoothing modes that were difficult to test experimentally. The study identified the most significant factors that influenced the formation of the maximum values of residual stresses in the surface layer of gate assemblies of high-pressure valves. The maximum values of compressive residual stresses, the value of which did not exceed the yield strength of the material were determined.

Modeling Residual Stresses in Superduplex Stainless Steel Welded Pipes Using the Finite Element Method

2013 ◽  
Vol 758 ◽  
pp. 1-10
Author(s):  
Fabiano Rezende ◽  
Luís Felipe Guimarães de Souza ◽  
Pedro Manuel Calas Lopes Pacheco
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Stainless Steel ◽  
Residual Stresses ◽  
Welding Process ◽  
Welding Parameters ◽  
Superduplex Stainless Steel ◽  
Mechanical Components ◽  
Element Method

Welding is a complex process where localized and intensive heat is imposed to a piece promoting mechanical and metallurgical changes. Phenomenological aspects of welding process involve couplings among different physical processes and its description is unusually complex. Basically, three couplings are essential: thermal, phase transformation and mechanical phenomena. Welding processes can generate residual stress due to the thermal gradient imposed to the workpiece in association to geometric restrictions. The presence of tensile residual stresses can be especially dangerous to mechanical components submitted to fatigue loadings. The present work regards on study the residual stress in welded superduplex stainless steel pipes using experimental and a numerical analysis. A parametric nonlinear elastoplastic model based on finite element method is used for the evaluation of residual stress in superduplex steel welding. The developed model takes into account the coupling between mechanical and thermal fields and the temperature dependency of the thermomechanical properties. Thermocouples are used to measure the temperature evolution during welding stages. Instrumented hole drilling technique is used for the evaluation of the residual stress after welding process. Experimental data is used to calibrate the numerical model. The methodology is applied to evaluate the behavior of two-pass girth welding (TIG for root pass and SMAW for finishing) in 4 inch diameter seamless tubes of superduplex stainless steel UNS32750. The result shows a good agreement between numerical experimental results. The proposed methodology can be used in complex geometries as a powerful tool to study and adjust welding parameters to minimize the residual stresses on welded mechanical components.

On Axisymmetric Residual Stresses in Tubes With Longitudinally Nonuniform Stress Distribution

1993 ◽  
Vol 60 (2) ◽  
pp. 300-309 ◽  
Author(s):  
T. Nishimura
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stress Distribution ◽  
Residual Stresses ◽  
Diffraction Method ◽  
Residual Stress Distribution ◽  
New Method ◽  
Element Analysis ◽  
Simple Modification ◽  
X Ray

New equations for calculating residual stress distribution are derived from the theory of elasticity for tubes. The initial distribution of the stresses including the shearing stress is computed from longitudinal distributions of residual stresses measured by the X-ray methods at the surface after removal of successive concentric layers of material. For example, the residual stresses of a steel tube quenched in water were measured by the X-ray diffraction method. The new method was also applied to a short tube with hypothetical residual stress distribution. An alternative finite element analysis was made for a verification. The residual stresses computed by finite element modeling agreed well with the hypothetical residual stresses measured. This shows that good results can be expected from the new method. The equations can also be used for bars by simple modification.

scholarly journals MICRO-SCALE STUDY OF RESIDUAL STRESSES IN CR2O3 COATINGS SPRAYED BY APS

2020 ◽  
Vol 27 ◽  
pp. 42-47
Author(s):  
Franck Decroos ◽  
Cécile Langlade ◽  
Eric Bourillot ◽  
Geoffrey Darut ◽  
Manuel Francois
Keyword(s):  
Residual Stress ◽  
Stress State ◽  
Residual Stresses ◽  
Atmospheric Plasma ◽  
Forming Process ◽  
Characterization Methods ◽  
Residual Stress State ◽  
Microwave Microscopy ◽  
Early Failures ◽  
Material Forming

Whichever the application field, every material forming process generates residual stresses on the surface. While they are likely to enhance the aimed properties of the final mechanical part, these stresses may also drastically reduce them and result in early failures. Therefore, understanding the residual stress state remains a major challenge when coating complex parts, especially as most characterization methods at the microscopic scale involve specific sample preparation procedures which may affect the residual stresses field. This work investigates the residual stress state that exists in chromium oxide coatings deposited via Atmospheric Plasma Spray (APS), using two pioneering techniques featuring high spatial resolution: Scanning Microwave Microscopy and Raman Micro-Spectroscopy. The first technique combines the measurement of microwave electromagnetic capacities of a Vector Network Analyzer with the subnanometric resolution of an Atomic Force Microscope: it thus enables performing depth investigations at very accurately defined positions of the probe on the surface. The second technique relies on the principle of photons inelastic scattering and involves a laser beam aiming at the material sample: it allows a fine characterization of the microstructure as well as defects and stresses detection via molecular vibratory signatures. The investigation scale is limited here to a few cubic micrometers. Due to the highly localized scales of our investigations, which also depend on the device, the objective of our procedure required that the comparison should be made not on individual points but on definite mapped areas, every spot being analyzed and post-treated one after another, with optimum measuring parameters. Results have been correlated with XRD measurements to cross-check the average amount of stress observed over a wider area.

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