Finite Element Analysis for Restraint Intensity and Welding Residual Stress of the Lehigh Specimen Made of Ti80 Alloy

Ti80 alloy is one of the most commonly used marine titanium alloys but faces cold cracking risks in thick plate welding. Understanding the relationship between restraint intensity and welding residual stress is critical for industrial applications. This study employs finite element methods to quantify the restraint intensity of Lehigh specimens and establish its quantitative link with welding residual stress in Ti80 alloy. Simulations reveal that restraint intensity increases linearly with plate thickness and decreases linearly with slot depth. A binary linear regression model accurately predicts restraint intensity with relative error of less than 6%. Furthermore, welding simulations demonstrate that residual stress on the weld bead’s upper surface increases exponentially with restraint intensity, while the lower surface shows a linear increase. Exponential and linear fits were applied to predict residual stress on the upper and lower surface, respectively. Validation confirms prediction errors for residual stress are below 9%. This work provides a methodology to assess cracking susceptibility and residual stress in actual Ti80 components by matching restraint conditions with Lehigh specimens.