New Method for Estimating Residual Stresses in Pipe Made by Surfacing Weld

1995 ◽  
Vol 117 (3) ◽  
pp. 365-371 ◽  
Author(s):  
T. Terasaki ◽  
T. Akiyama ◽  
T. Ishimura
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
New Method ◽  
Composite Pipe ◽  
Inherent Strain ◽  
Inherent Strain Method ◽  
Strain Method

A new method is presented for estimating residual stresses produced in a pipe made by surfacing weld. By focusing on the concept and the feature of inherent strain causing the residual stress, the proposed method has both the convenience of the Sachs method and the accuracy of the inherent strain method. The experiment for residual stress of a steel with brass cladding was done by both the Sachs and proposed method. The equation of the Sachs method for composite pipe was derived. The equation for the new method was obtained on the basis of the theory of inherent strain. It is found that the proposed method is useful for estimating residual stresses of pipe with cladding.

Research on Deformation Prediction Method of Laser Melting Deposited Large-Sized Parts Based on Inherent Strain Method

2021 ◽  
Vol 871 ◽  
pp. 65-72
Author(s):  
Cheng Hong Duan ◽  
Xian Kun Cao ◽  
Ming Huang Zhao ◽  
Xiang Peng Luo
Keyword(s):  
Residual Stress ◽  
Laser Energy ◽  
Layer By Layer ◽  
Laser Melting ◽  
Forming Process ◽  
Deformation Prediction ◽  
Metal Parts ◽  
Inherent Strain ◽  
Inherent Strain Method ◽  
Strain Method

In the process of metal parts fabricated by Laser Melting Deposition (LMD), a high temperature gradient will generate due to the instantaneous high laser energy input, which will cause residual stress in the formed part of metal parts, the residual stress will result in defects like warping deformation or even cracking. In this paper, a finite element method based on inherent strain method is proposed to predict the deformation of metal parts fabricated by LMD. Firstly, combing with the birth and death element technology, a local model is established to simulate the layer-by-layer deposition in the LMD forming process, and the values of inherent strain is obtained. Secondly, the obtained inherent strain values is applied to large-sized part layer by layer, and the final deformation of large-sized part is calculated. Based on the proposed method, the efficiency of deformation prediction of large-sized metal parts fabricated by LMD could be effectively improved.

scholarly journals An inverse approach for constructing the residual stress field induced by welding

2002 ◽  
Vol 37 (4) ◽  
pp. 345-359 ◽  
Author(s):  
Y P Cao ◽  
N Hu ◽  
J Lu ◽  
H Fukunaga ◽  
Z. H Yao
Keyword(s):  
Experimental Data ◽  
Residual Stress ◽  
Stress Field ◽  
Residual Stresses ◽  
Strain Field ◽  
Basis Functions ◽  
Residual Stress Field ◽  
Inverse Approach ◽  
Inherent Strain ◽  
Inherent Strain Method

In this paper, an inverse approach based on the inherent strain method has been proposed for constructing the residual stress field induced by welding. Firstly, some smooth basis functions in the form of polynomials have been employed to approximate inherent strains. To select the basis functions properly, previous valuable knowledge about distributions of residual stresses for some typical welding structures should be considered. Furthermore, singular modes in the assumed inherent strain that do not cause residual stresses should be excluded. In this way, a stable profile of the inherent strain field can be assumed. Secondly, by employing the finite element method (FEM) and the least-squares technique, the inherent strain field can be identified from the experimental data at some key points. The proper selection of positions of experimental points has also been considered. Finally, the distribution of residual stresses can be constructed efficiently by using the obtained inherent strain field. Compared with the traditional inherent strain method, in the present work the sensitivity matrix for predicting inherent strains can be evaluated more effectively and experimental data needed in the identification procedure can be reduced significantly. Some typical examples have been presented to demonstrate the effectiveness of the present method.

Inherent Strain Method for Residual Stress Measurement and Welding Distortion Prediction

2016 ◽  
Author(s):  
Ninshu Ma ◽  
Keiji Nakacho ◽  
Takahiko Ohta ◽  
Naoki Ogawa ◽  
Akira Maekawa ◽  
...  
Keyword(s):  
Residual Stresses ◽  
Welded Joints ◽  
Stress Measurement ◽  
Three Dimensional ◽  
Diffraction Method ◽  
Welding Distortion ◽  
Fast Prediction ◽  
Inherent Strain ◽  
Inherent Strain Method ◽  
Strain Method

Inherent strain method was employed to measure the distribution of three dimensional welding residual stresses in several multi-pass welded joints of thick pipes and thick cladded plates. Since a function expression approach to the distribution of inherent strains was developed, the measuring efficiency for three dimensional internal welding residual stresses in complicated welded joints was improved a lot. The residual stresses measured by inherent strain method were compared with the high cost stress release method and neutron diffraction method. Furthermore, inherent deformation parameters, which are defined by integrated values of inherent strains on transverse sections, were used for the fast prediction of welding distortion in assembling structures. Based the predicted welding distortion, its mitigation methods such as tack welding and jig constraint were discussed.

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