Using X-Ray Diffraction and Finite Element Method to Analyze Residual Stress of Tube-to-Tubesheet Welded Joints in a Shell and Tube Heat Exchanger

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
Yu Wan ◽  
Wenchun Jiang ◽  
Yun Luo
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Heat Exchanger ◽  
Residual Stresses ◽  
Heat Input ◽  
X Ray Diffraction ◽  
X Ray ◽  
Tube Heat Exchanger ◽  
Shell And Tube

A lot of failures have been generated in the tube-to-tubesheet joints of a shell and tube heat exchanger, which are greatly affected by the weld residual stresses. In order to ensure the structure integrity, it is very important to predict and decrease the residual stress in the joint between tube and tubesheet. In this paper, a combination of X-ray diffraction and finite element method (FEM) was used to analysis the residual stress distribution in the tube-to-tubesheet joints. The formation mechanism of residual stress before and after cosmetic welding was explicated. The effects of heat input and welding sequence on residual stresses were studied. The results show that the large tensile residual stresses which are in excess of yield strength, are generated in the tube-to-tubesheet joints. The residual stresses at the bottom surface and the edge of the tubesheet are relatively small even become compressive. The formation of the weld residual stress is mainly induced by the cosmetic welding rather than the back welding. The residual stresses increase as the heat input increases. The duplex welding method is recommended to decrease the residual stress.

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.

An Experimental and Numerical Investigation of Residual Stresses in Butt Welding of Two Mild Steel Plates

2011 ◽  
Author(s):  
Gurdeep Singh ◽  
Gurinder Singh Brar
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Mild Steel ◽  
Diffraction Method ◽  
Element Model ◽  
Steel Plates ◽  
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) are carried out to calculate the residual stress values in the welded plates. A three-pass V-butt weld joint is 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 Simulation software is used to develop a 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. It can also be concluded that when temperature distribution increases then the residual stress in the weldment also increase. 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 Effect of a Multiple Reduction Die on the Residual Stress of Drawn Materials

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1358
Author(s):  
Jeong-Hun Kim ◽  
Chang-Hyun Baek ◽  
Sang-Kon Lee ◽  
Jong-Hun Kang ◽  
Joon-Hong Park ◽  
...  
Keyword(s):  
Neural Network ◽  
Residual Stress ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Residual Stresses ◽  
Deep Neural Network ◽  
Drawing Process ◽  
X Ray Diffraction ◽  
Element Analysis ◽  
X Ray

Residual stress may influence the mechanical behavior and durability of drawn materials. Thus, this study develops a multiple reduction die (MRD) that can reduce residual stress during the drawing process. The MRD set consists of several die tips, die cases, and lubricating equipment. All the die tips of the MRD were disposed of simultaneously. Finite element analysis of the drawing process was performed according to the reduction ratio of each die tip, and the variables in drawing process with the MRD were optimized using a deep neural network to minimize the residual stress. Experiments on the drawing process with the conventional die and MRD were performed to evaluate the residual stress and verify the effectiveness of the MRD. The results of X-ray diffraction measurements indicated that the axial and hoop residual stresses on the surface were dramatically reduced.

Residual Stress Characterization of A7N01-T5 Welds for High Speed Train by X-Ray Diffraction and Verification

2011 ◽  
Vol 291-294 ◽  
pp. 896-900
Author(s):  
Hua Ji ◽  
Guo Qing Gou ◽  
Hui Chen ◽  
Da Li ◽  
Chuan Ping Ma ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Residual Stresses ◽  
High Speed ◽  
High Speed Train ◽  
X Ray Diffraction ◽  
Good Qualitative Agreement ◽  
X Ray ◽  
Method Show

Welding residual stresses have an effect on many aspects of the integrity of structures but are normally one of the largest unknown stresses. Residual stresses are difficult to measure and to estimate theoretically but are often significant when compared with the service stresses. In this paper, measurement of residual stresses by X-ray diffraction technique using two different fitting methods (Gaussian and PearsonⅦ) was compared with analysis of a sample geometry by theoretical finite-element methods. The square map RS characterization of A7N01-T5 welds was shown. The results indicate RS measured by XRD and simulated by finite-element method show good qualitative agreement.

Micro-slotting technique for reliable measurement of sub-surface residual stress in Ti-6Al-4V

2018 ◽  
Vol 53 (6) ◽  
pp. 389-399 ◽  
Author(s):  
Elizabeth Burns ◽  
Joseph Newkirk ◽  
James Castle
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Image Correlation ◽  
X Ray Diffraction ◽  
Surface Residual Stress ◽  
Near Surface ◽  
X Ray ◽  
Measurement Volume ◽  
Surface Residual Stresses

Micro-slotting, a relaxation residual stress measurement technique, has recently been shown to be an effective method for measuring local residual stresses in a variety of materials. The micro-slotting method relies on a scanning electron microscope–focused ion beam system for milling and imaging, digital image correlation software to track displacements due to residual stress relaxation after milling, and finite element analysis for displacement–stress correlation and calculation of the original stress state in the imaged region. The high spatial resolution of the micro-slotting method makes it a promising technique for obtaining near-surface residual stress data in Ti-6Al-4V components for input into fatigue life models and crack growth simulations. However, use of the micro-slotting method on this alloy has yet to be evaluated against more established measurement techniques. In this study, spatially resolved sub-surface residual stress measurements were obtained on shot peened and low-stress surface-machined Ti-6Al-4V planar coupons using the micro-slotting method and were compared to measurements obtained using the conventional X-ray diffraction depth profiling technique. The sub-surface measurements were in good agreement for the shot peened sample. Observed differences in the measured near-surface residual stresses on the surface-machined sample were attributed to the larger measurement volume of the X-ray diffraction method, suggesting that the micron-sized measurement volume of the micro-slotting method may be more suitable for capturing shallow stress profiles and steep stress gradients. Prior to performing the micro-slotting measurements, finite element modeled displacements were used to verify the measurement procedure and to address uncertainties in the milled slot geometries. The results of this study demonstrated the validity of the micro-slotting procedure and established the technique as a reliable method for measuring sub-surface residual stresses in Ti-6Al-4V.

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.

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