Dynamic Simulation of Stress Field During Surfacing Process Based on ANSYS Finite Element Analysis

Literature Overview

This 2010 publication by Li Yilei, Bai Qinghua, and Ma Yuejin from Hebei Agricultural University, appearing in Welding Technology (Vol. 39, Issue 8, pp. 13-15), presents a three-dimensional real-time dynamic finite element simulation of the stress and strain field evolution during a plate surfacing welding process. The study was supported by the Hebei Provincial Natural Science Foundation (Project E2006000528). The work employs ANSYS finite element analysis software with contact element technology to model the progressive deposition of surfacing layers and the associated thermal-mechanical interactions. This research contributes to the growing body of computational welding mechanics literature that seeks to predict and control residual stress and deformation in surfacing applications.

Numerical Simulation Methodology

The simulation approach involves a sequential layer-by-layer deposition model, where each surfacing pass is added to the model as a new set of elements that are activated during the welding cycle. The contact element technology is used to model the interface between the newly deposited layer and the previously solidified material, accounting for the complex contact conditions that evolve during heating, melting, and solidification. The thermal analysis provides the temperature field history, which is then mapped to the mechanical analysis to compute the stress and strain state at each time step.

The key results indicate that during the welding process, the material in the welding zone undergoes plastic thermal compression due to the thermal expansion of the molten and hot metal. Upon cooling, the welding region is left in a state of tensile residual stress, while the surrounding base material experiences compressive residual stress. This stress distribution pattern is consistent with the well-established thermal contraction theory of welding residual stress.

Residual Stress Analysis and Crack Prevention

The paper emphasizes that the dynamic stress-strain process during welding and the subsequent residual stress field are primary factors contributing to welding cracking and degradation of joint strength and performance. The authors highlight the effectiveness of peening (hammering) treatment as a post-weld process for reducing residual stress and preventing crack formation. Peening introduces compressive residual stress at the surface by plastically deforming the weld metal, which counteracts the tensile residual stress generated during welding.

From a quality assurance perspective, the ability to predict residual stress magnitude and distribution through finite element simulation enables proactive process optimization. Engineers can adjust welding parameters such as heat input, interpass temperature, and welding sequence to minimize peak tensile stress and reduce the risk of hot cracking and cold cracking. The simulation also provides insight into the effectiveness of stress relief measures such as peening and post-weld heat treatment, allowing for more informed selection of post-weld processes.

Study Insights and Practical Recommendations

This paper exemplifies the growing importance of computational methods in welding engineering, particularly for complex surfacing applications where experimental measurement of stress fields is difficult or impractical. The sequential deposition modeling approach used here is now a standard methodology in advanced welding simulation software. For practitioners in the pipe and fitting industry, the key takeaway is that residual stress management should be an integral part of surfacing procedure qualification, not merely a post-weld corrective measure. Incorporating finite element analysis into the procedure development phase can lead to more robust and reliable surfacing processes, particularly for critical applications involving high-strength steels, thick-section components, or service environments where stress corrosion cracking is a concern.