Investigation of thermal residual stresses in layered composite using the finite element method and X-ray diffraction

1997 ◽  
Vol 28 (6) ◽  
pp. 969-978 ◽  
Author(s):  
S. Ho ◽  
E. J. Lavernia
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Residual Stresses ◽  
Layered Composite ◽  
The Finite Element Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thermal Residual Stresses ◽  
Element Method

Three-phase micromechanical analysis of residual stresses in reinforced fiber by carbon nanotubes

2016 ◽  
Vol 51 (12) ◽  
pp. 1783-1794 ◽  
Author(s):  
Ahmad Reza Ghasemi ◽  
Mohammad Mohammadi Fesharaki ◽  
Masood Mohandes
Keyword(s):  
Finite Element Method ◽  
Carbon Nanotubes ◽  
Finite Element ◽  
Carbon Fiber ◽  
Residual Stresses ◽  
Representative Volume Element ◽  
Volume Element ◽  
The Finite Element Method ◽  
Representative Volume ◽  
Element Method

In this study, circular disk model and cylinder theory for two dimension (2D) and three dimension (3D), respectively, have been used to determine residual stresses in three-phase representative volume element. The representative volume element is consisting of three phases: carbon fiber, carbon nanotubes, and polymer matrix, that carbon fiber is reinforced by carbon nanotube using electrophoresis method. Initially, the residual stresses analysis of two-phase representative volume element has been implemented. The two-phase representative volume element has been divided to carbon fiber and matrix phases with different volume fractions. In the three-phase representative volume element, although the volume fraction of carbon fiber is constant and equal to 60%, the volume fractions of carbon nanotubes for various cases are different as 0%, 1%, 2%, 3%, 4%, and 5%. Also, there are two different methods to reinforce the fiber according to different coefficients of thermal expansion of the carbon fiber and carbon nanotube in two longitudinal and transverse directions; carbon nanotubes are placed on carbon fiber either parallel or around it like a ring. Subsequently, finite element method and circular disk model have been used for analyzing micromechanic of the residual stresses for 2D and then the results of stress invariant obtained by the finite element method have been compared with the circular disk model. Moreover, for 3D model, the finite element method and cylinder theory have been utilized for micromechanical analysis of the residual stresses and the results of stress invariant obtained by them, have been compared with each other. Results of the finite element method and analytical model have good agreement in 2D and 3D models.

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.

Prediction of Residual Stresses in Butt Welded Plates Using Inherent Strains

1993 ◽  
Vol 115 (4) ◽  
pp. 417-423 ◽  
Author(s):  
Y. Ueda ◽  
M. G. Yuan
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
The Finite Element Method ◽  
Butt Weld ◽  
Butt Welds ◽  
Plastic Analysis ◽  
Inherent Strain ◽  
Element Method

The source of residual stresses in the vicinity of a weld may be expressed in terms of inherent strains. The characteristics of the inherent strain distributions in butt welds are investigated. It is found that the patterns vary little with changes in the welding conditions and sizes of the welded plates. With some assumptions, simple formulas are derived for the distribution and magnitude of inherent strain in a butt weld. A method of predicting the residual stress in a butt-welded plate using the characteristics of inherent strain distributions is presented. The validity of the method is confirmed by thermal elasto-plastic analysis using the finite element method (FEM).

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.

scholarly journals Modeling and Calculating of Residual Stress and Strain of Butt Welded Joint

2021 ◽  
Vol 31 (5) ◽  
pp. 58-67
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Welded Joint ◽  
The Finite Element Method ◽  
Force Method ◽  
Stress Components ◽  
Residual Stresses And Strains ◽  
Element Method

The non-uniform thermal expansion and contraction resulting from welding processes cause residual stresses and strains. Experimental studies on measuring welding residual stresses and strains of structure are costly and sometimes they are not possible. Previously, analytical methods with idealized models were developed to determine the welding residual stresses and strain. Recently, numerical methods are constructed to analyze the stresses and the strains in welded structures. This paper presents the calculation results of residual stress and welding strain in butt welded joint of S355J2G3 carbon steel of 5 mm thickness made by MAG welding process with a single pass. The calculation is performed by two methods: the imaginary force method and the finite element method. In the finite element method, the SYSWELD software is used to simulate and to determine residual stresses and strain of this welded joint. The results of finite element method are compared with those of imaginary force method to show the rationality and the advantages of finite element method. The study results have shown that in this welded joint, only the longitudinal and transverse stress components are important and the other stress components are negligible.

Sign in / Sign up

Export Citation Format

Share Document