scholarly journals Residual Stress Evaluation of Carburized Transmission Steel Gear Using Neutron and Synchrotron X-Ray Diffraction and Finite Element Methods

2010 ◽  
Vol 652 ◽  
pp. 31-36 ◽  
Author(s):  
Yoshihisa Sakaida ◽  
Takanori Serizawa ◽  
M. Kawauchi ◽  
M. Manzanka
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Neutron Diffraction ◽  
Carbon Content ◽  
Residual Strain ◽  
Stress Fields ◽  
X Ray ◽  
Residual Strains ◽  
Transmission Gear

A motorcycle transmission gear of chromium-molybdenum steel with 0.2%C was carburized in carrier gas. Carburizing process including heating, carburizing, diffusing and quenching was simulated using elastoplastic finite element method. The carbon content, hardness, residual strain and residual stress fields of gear were analyzed. The unstressed lattice plane spacing and residual strains of the interior near the internal spline of gear were experimentally measured by synchrotron x-ray and neutron diffraction methods. As a result, the analyzed carbon content and hardness gradients of gear accorded with the experimental results. The radial, hoop and axial directions of cylindrical gear were found to be not always principal axes of residual stress field. On the other hand, the analyzed residual strains in the radial, hoop and axial directions of gear slightly discorded with the experimental results. Although correlation between the measured three strains was similar to that of the weighted average of analyzed strains, residual strain and stress fields of motorcycle transmission gear could not be accurately predicted at the present finite element analysis. It was concluded that carbon diffusion phenomenon and resultant hardening could be analyzed by the finite element method, and the actual interior residual strain and stress fields should be nondestructively measured by neutron diffraction method.

Design Optimisation of a Ferritic Ring Weld Specimen Using FE Modelling

2009 ◽  
Author(s):  
Christopher M. Gill ◽  
Paul Hurrell ◽  
John Francis ◽  
Mark Turski
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Finite Element ◽  
Neutron Diffraction ◽  
Stress Field ◽  
Finite Element Modelling ◽  
Post Weld Heat Treatment ◽  
Stress Fields ◽  
Element Modelling ◽  
Weld Heat

This paper describes the design optimisation of an SA508 ferritic steel ring weld specimen using FE modelling techniques. The aim was to experimentally and analytically study the effect of post weld heat treatment upon a triaxial residual stress field. Welding highly constrained geometries, such as those found in some pressure vessel joints, can lead to the formation of highly triaxial stress fields. It is thought that application of post weld heat treatments will not fully relax hydrostatic stress fields. Therefore a ferritic multi-pass ring weld specimen was designed and optimised, using 2D finite element modelling, to generate a high magnitude triaxial stress field. The specimen thickness and weld-prep geometry was optimised to produce a large hydrostatic stress field and still allow efficient use of neutron diffraction to measure the residual stress. This paper reports the development of the test specimen geometry and compares the results of welding FE analysis and neutron diffraction measurements. Welding residual stresses were experimentally determined using neutron diffraction; both before post weld heat treatment. Three dimensional moving heat source weld finite element modelling has been used to predict the residual stresses generated by the welding process used. Finite element modelling examined the effect of phase transformation upon the residual stress field produced by welding. The relaxation of welding stresses by creep during post weld heat treatment has also been modelled. Comparisons between the modelled and measured as-welded residual stress profiles are presented. This work allows discussion of the effect of post weld heat treatment of triaxial stress fields and determines if finite element modelling is capable of correctly predicting the stress relaxation.

Residual Stress Measurements in Continuous Fiber Titanium Matrix Composites

1992 ◽  
Vol 36 ◽  
pp. 481-488 ◽  
Author(s):  
M. R. James ◽  
M. A. Bourke ◽  
J. A. Goldstone ◽  
A. C. Lawson
Keyword(s):  
Residual Stress ◽  
Neutron Diffraction ◽  
Thin Sheet ◽  
Matrix Composites ◽  
X Ray ◽  
Residual Stress State ◽  
Longitudinal Residual Stress ◽  
The Matrix ◽  
Reinforcement Fiber ◽  
Residual Strains

AbstractMetal matrix composites develop residual strains after consolidation due to the thermal expansion mismatch between the reinforcement fiber and the matrix. X-ray and neutron diffraction measured values for the longitudinal residual stress in the matrix of three titanium MMCs are reported. For thick composites (> 6 plies) the surface stress measured by x-ray diffraction matches that determined by neutron diffraction and therefore represents the stress in the bulk region consisting of the fibers and matrix. For thin sheet composites, the surface values are lower than in the interior and increase as the outer rows of fibers are approached. While a rationale for this behavior has yet to be developed, accounting for composite thickness is important when using x-ray measured values to validate analytic and finite element calculations of the residual stress state.

Predictions of Residual Stresses in the Mechanical Roll Expansion of HX Tubes Into TEMA Grooves

2003 ◽  
Author(s):  
Dennis K. Williams
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Stainless Steel ◽  
Tube Wall ◽  
Initial Study ◽  
Stress Fields ◽  
The Finite Element Method ◽  
Residual Stress Field ◽  
Steel Tubes

The mechanical roll expansion of heat exchanger tubes into tubesheets containing TEMA grooves, which are thought to aid in the mechanical integrity of the tube-to-tubesheet (TTT)joint, has for many years provided an acceptable means of completing a TTT joint. Inherent with the intentional roll expansion of the tube is the creation of a tensile residual stress field within the tube that is greatest in the transition region between the expanded and unexpanded zones of the tube. An additional complicating factor in the tube-to-tubesheet joint design is the choice of utilizing a seal weld or a “full strength” weld at the tube end in conjunction with a level of roll expansion quantified by the degree of tube wall reduction. This paper presents the results of an initial study of the mechanical roll expansion of 1 inch diameter tubes into a typical TEMA-R designed tubesheet, utilizing two grooves in the tubesheet hole. Two combinations of tube and tubesheet materials are studied that include duplex stainless steel tubes and tubesheet, while the second combination includes type 321 tubes roll expanded into a 2-1/4 Cr-1 Mo tubesheet, clad with 321 SS overlay. The predicted residual stress fields are calculated by the finite element method and employ a simplified two dimension nonlinear axisymmetric model.

scholarly journals Characterization of the Microstructure, Local Macro-Texture and Residual Stress Field of Commercially Pure Titanium Grade 2 Prepared by CONFORM ECAP

Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1000 ◽  
Author(s):  
Gergely Németh ◽  
Klaudia Horváth ◽  
Charles Hervoches ◽  
Petr Cejpek ◽  
Jan Palán ◽  
...  
Keyword(s):  
Residual Stress ◽  
Neutron Diffraction ◽  
Grain Refinement ◽  
Residual Strain ◽  
Pure Titanium ◽  
Asymmetric Distribution ◽  
Commercially Pure Titanium ◽  
X Ray ◽  
Commercially Pure ◽  
Titanium Grade

The paper investigated the residual strain and stress distribution, microstructure, and macro-texture along the transverse direction of commercially pure titanium grade 2 samples prepared by the CONFORM ECAP technique. This method belongs to the severe plastic deformation methods; hence, it could be assumed that residual stress fields would be present in the work-pieces. Residual stresses cannot be directly measured; thus, neutron diffraction measurements, Electron back-scatter diffraction (EBSD) investigations, and local X-ray macro-texture measurements were performed in different regions of the sample to determine the data for the residual stress calculation. The calculation was based on the modified Kröner model. Neutron diffraction strain scans and residual stress calculations revealed that symmetrical residual strain and stress gradients with compression character were present in the axial and hoop direction after one and two passes. Asymmetric distribution of the residual strains and stresses remained after the third pass of the CONFORM ECAP. EBSD investigations showed that after the first pass, significant grain refinement occurred; however, further passes did not cause any dramatic grain refinement. X-ray texture measurements revealed that local macro-texture was dependent on the number of passes of the CONFORM ECAP and on the investigated area in the samples.

Residual Stresses in Butt Welding of Two Circular Pipes: An Experimental and Numerical Investigation

2014 ◽  
Author(s):  
Gurinder Singh Brar
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Finite Element Model ◽  
Welding Process ◽  
Diffraction Method ◽  
Element Model ◽  
X Ray Diffraction ◽  
X Ray

Welding is a reliable and efficient joining process in which the coalescence of metals is achieved by fusion. Welding is carried out with a very complex thermal cycle which results in irreversible elastic-plastic deformation and residual stresses in and around fusion zone and heat affected zone (HAZ). A residual stress due to welding arises from the differential heating of the plates due to the weld heat source. Residual stresses may be an advantage or disadvantage in structural components depending on their nature and magnitude. The beneficial effect of these compressive stresses have been widely used in industry as these are believed to increase fatigue strength of the component and reduce stress corrosion cracking and brittle fracture. But due to the presence of residual stresses in and around the weld zone the strength and life of the component is also reduced. To understand the behavior of residual stresses, two 10 mm thick Fe410WC mild steel plates are butt welded using the Metal Active Gas (MAG) process. An experimental method (X-ray diffraction) and numerical analysis (finite element analysis) were then carried out to calculate the residual stress values in the welded plates. Three types of V-butt weld joint — two-pass, three-pass and four-pass were considered in this study. In multi-pass welding operation the residual stress pattern developed in the material changes with each weld pass. In X-ray diffraction method, the residual stresses were derived from the elastic strain measurements using a Young’s modulus value of 210 GPa and Poisson’s ratio of 0.3. Finite element method based, SolidWorks software was used to develop coupled thermal-mechanical three dimension finite element model. The finite element model was evaluated for the transient temperatures and residual stresses during welding. Also variations of the physical and mechanical properties of material with the temperature were taken into account. The numerical results for peak transverse residual stresses attained in the welded plates for two-pass, three-pass and four-pass welded joint were 67.7 N/mm2, 58.6 N/mm2, and 48.1 N/mm2 respectively. The peak temperature attained during welding process comes out to be 970°C for two-pass weld, 820.8°C for three-pass weld and 651.9°C for four-pass weld. It can be concluded that due to increase in the number of passes during welding process or deposition weld beads, the residual stresses and temperature distribution decrease. Also, the results obtained by finite element method agree well with those from experimental X-ray diffraction method.

Residual Stress Evaluation of Railway Wheels by X-Ray Diffraction and Finite Element Method

2010 ◽  
Vol 89-91 ◽  
pp. 545-550
Author(s):  
Shunichi Takahashi ◽  
Takanori Kato ◽  
Hiroshi Suzuki ◽  
Toshihiko Sasaki
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Stress State ◽  
Fem Analysis ◽  
X Ray Diffraction ◽  
Stress Release ◽  
X Ray ◽  
Railway Wheels ◽  
Hoop Direction

X-ray stress measurement is useful for determining, in a non-destructive manner, the surface stresses of engineered parts.　However, the railway wheels cannot measure because this it is very large. So it should be measured using a scaled-down model. The problem is, however, how the stress release should be considered. In this analysis, the finite element method (FEM) was applied to estimate the initial stress state using stresses released after cutting a sample obtained by the X-ray method. Railway wheels were studied in this experiment. In the early 1990s, several railroads in the northeast of the U.S.A. experienced extensive cracking in the wheels of the commuter trains. Residual stresses in the hoop direction play an important role in mechanism fatigue damage. This paper will discuss about residual stress in the hoop direction in manufactured wheels. The results of FEM analysis and the X-ray diffraction method confirms that these methods can be used to evaluate the residual stress of the hoop direction. There is very good quantitative agreement between the simulated and measured stress distributions. It can be suggested that guessing guess stress release and the redistribution by the FEM analysis is possible. The residual hoop stress of the unused wheel presumed by this research has the residual stress of high compression in the wheel at the center of the rim up to 40mm depth.　It is very safe because the residual stress state is compressive even when a crack occurs, and obstructs the crack’s progress. If a crack occurs by any chance, the stress state can obstruct the crack’s progress.

scholarly journals Finite Element Simulation and X-Ray Microdiffraction Study of Strain Partitioning in a Layered Nanocomposite

2016 ◽  
Vol 2016 ◽  
pp. 1-11
Author(s):  
R. I. Barabash ◽  
V. Agarwal ◽  
S. Koric ◽  
I. Jasiuk ◽  
J. Z. Tischler
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Three Dimensional ◽  
Growth Direction ◽  
Strain Partitioning ◽  
X Ray ◽  
Element Simulation ◽  
Dependent Strain ◽  
Residual Strains ◽  
Three Dimensional Simulations

The depth-dependent strain partitioning across the interfaces in the growth direction of the NiAl/Cr(Mo) nanocomposite between the Cr and NiAl lamellae was directly measured experimentally and simulated using a finite element method (FEM). Depth-resolved X-ray microdiffraction demonstrated that in the as-grown state both Cr and NiAl lamellae grow along the 111 direction with the formation of as-grown distinct residual ~0.16% compressive strains for Cr lamellae and ~0.05% tensile strains for NiAl lamellae. Three-dimensional simulations were carried out using an implicit FEM. First simulation was designed to study residual strains in the composite due to cooling resulting in formation of crystals. Strains in the growth direction were computed and compared to those obtained from the microdiffraction experiments. Second simulation was conducted to understand the combined strains resulting from cooling and mechanical indentation of the composite. Numerical results in the growth direction of crystal were compared to experimental results confirming the experimentally observed trends.

Measurement of Residual Strain in Cold Spray Process Using X-Ray Diffraction and Finite Element Method

2011 ◽  
Vol 214 ◽  
pp. 245-249 ◽  
Author(s):  
Thanh Duoc Phan ◽  
Syed H. Masood ◽  
Saden H. Zahiri ◽  
Mahnaz Z. Jahedi
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Cold Spray ◽  
Residual Strain ◽  
Spray Coating ◽  
Industrial Applications ◽  
Element Analysis ◽  
X Ray ◽  
Peak Broadening ◽  
Element Method

Cold spray technology has the potential to be utilised in broader industrial applications especially for oxygen-sensitive materials such as titanium. In this paper, the effect of titanium cold spray coating on residual strain after deposition is evaluated. Ring-shaped sample of 16.5 mm diameter was directly fabricated from titanium powder by cold spray. Using an X-ray diffractometer (XRD) and finite element analysis (FEA), the coating surface was analysed and compared. The XRD measurements revealed that residual strain at the sample surface (εXRD) was around 0.140. There was also some X-ray peak broadening of steel, which may be related to presence of porosity in unpolished samples. In addition, a good correlation was found (εFEA ≈ 0.169) when the residual strain results obtained from FEA were compared with the conducting test outcomes. Therefore, finite element method can be considered as a cost effective tool in quantification of strain in cold spray titanium structure.

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