Development of a new combined heat source model for welding based on a polynomial curve fit of the experimental fusion line

• Published in: International journal of advanced manufacturing technology Vol. 87; no. 5-8; pp. 1985 - 1997
• Main Authors: Wang, Junqiang, Han, Jianmin, Domblesky, Joseph P., Yang, Zhiyong, Zhao, Yingxin, Zhang, Qiang
• Format: Journal Article
• Language: English
• Published: London Springer London 01.11.2016; Springer Nature B.V
• Subjects: Arc heating; Arc welding; CAE) and Design; Computer simulation; Computer-Aided Engineering (CAD; Cross-sections; Curvature; Density distribution; Electric power distribution; Engineering; Finite element method; Fusion welding; High strength alloys; High temperature effects; Industrial and Production Engineering; Matching; Mechanical Engineering; Media Management; Model accuracy; Normal distribution; Original Article; Polynomials; Power sources; Residual stress; Simulation; Finite element modeling; Gaussian heat source; GMA welding; Residual stress; Welding distortion
• ISSN: 0268-3768; 1433-3015
• DOI: 10.1007/s00170-016-8587-3

To improve the accuracy of finite element (FE) models used to simulate electric arc and beam-based fusion welding processes, a combined heat source model is proposed. The combined model, termed the polynomial heat source, is based on a Gaussian heat density distribution and employs a disc source to account for surface heating effects while a polynomial equation is used to define the volumetric heat power source. This provides an improved capability for matching the heat source power distribution to fusion zones having variable curvature and also results in a simplified process for defining heat source parameters as only three numerical values need to be determined. To validate the heat source model, fusion zone cross sections, thermal cycles, angular distortion, and residual stresses obtained using SYSWELD were compared to measurements taken from gas metal arc (GMA) welds made on 10-mm-thick high-strength low-alloy (HSLA) plates. Predictions obtained from SYSWELD using double ellipsoid and conical heat source models were also compared. An analysis of the FE predictions obtained from each of the three heat source models showed that the best agreement between simulated and experimental values was achieved using the polynomial model. This is attributed to the fact that heat power distribution can be adjusted at the top and bottom of the fusion zone and results in an improved level of bead cross section matching. It is expected that the proposed heat source model will be applicable for simulating both shallow and deep penetration welding processes where the fusion zone is symmetric about its centerline.