welding is one of the most important assembling methods which are widely applied in different applications. in service conditions, some of the weld joints which meet defects must be repaired. the residual stresses impress the operation and efficiency of the repair weldment. in this study, the temperature and the residual stress fields were investigated by both the finite element simulation and ...

Ill EXECUTIVE SUMMARY IV

The present work evaluates the application of artificial neural networks for pattern recognition of ultrasonic signals using pulse-echo and TOFD (Time of Flight Diffraction) techniques in weld beads. In this study pattern classifiers are implemented by artificial neural network of backpropagation type using MATLAB. The ultrasonic signals acquired from pulse-echo and TOFD were introduced, separ...

Two different cases regarding the zinc coating at the lap joint faying surface are selected for studying the influence of zinc vapor on the keyhole dynamics of the weld pool and the final welding quality. One case has the zinc coating fully removed at the faying surface; while the other case retains the zinc coating on the faying surface. It is found that removal of the zinc coating at the fayi...

Ultrasonic inspection of dissimilar welds is still a challenge due to the different acoustic impedances across the interfaces between parent metals, welded, butter or cladded regions. Typically parent metals are fine grained carbon/ferritic/20MnMoNi55 steel, which show isotropic character. Whereas weld/butter/cladded metals are INCONEL/ austenitic steel, which exhibit anisotropic character, att...

A three-dimensional (3D) finite element (FE) model is applied to predict the temperature evolution in the laser welding of galvanized high-strength steels in a zero-gap lap joint configuration. A rotary Gaussian volumetric heat source model is introduced to simulate the laser energy input. The temperature data measured by thermocouples are used to verify the boundary conditions of the thermal m...

Partial differential equation (PDE)–based image processing has played a substantial role and become more popular in the recent years. In the application of weld defect detection, the PDE models can be applied for image smoothing and segmentation. In this study, anisotropic diffusion proposed by Perona Malik known as Perona Malik Anisotropic Diffusion (PMAD) model is used as a denoising process ...

Weldments are particularly susceptible to fracture due to defects, material property variations, and residual stresses created during the welding process. It is common in fracture assessments of welded structures to ignore these features; defects are often idealized to be crack-like, weld properties to be homogeneous, and residual stresses to be uniaxial and tensile or nonexistent. This paper p...