TIG焊接下AISI 4130车架钢管有限元分析与多尺度疲劳寿命评估

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Abstract： This study systematically investigates the mechanical properties and fatigue characteristics of AISI 4130 chassis stee tubes under TIG welding processs，focusing on the U2O rollcage welding right-angle butt joint specimens from the China SAE Baja Competition.A thermomechanical coupled finite element model based on the Goldak double elipsoid heat source wasconstructed to dynamically simulate the welding temperature field and residual stress field using ANsYs Workbench.A multiaxial fatigue life evaluation system integrating the mean stress-corrected Morrow model and the E-Ncurve method was established via nCode Design Life. Innovatively adopting response surface methodology to optimize welding parameters，a three-factor three-level orthogonal experiment revealed thatoptimalweld qualityisachieved at weldingspeed of 3mm/s ，weldingdurationof2Os，and power density of 40W/mm2 .Under these conditions，the weld penetration reached 3.2mm ，with an 18% improvement inweld width uniformity，a residual stresspeak reduction to 285MPa ，andamaximumdeformation of 0.08mm representing a 23% enhancement in forming quality compared to conventional parameters.Microstructural analysis indicated refined grain sizes （12～15μm） in the weld zone and a 37% reduction in hardness gradient within the heat-affected zone.Multibody dynamics-based load spectrum analysis demonstrated spatially graded fatigue life distributions： the minimum fatigue life of 7.37×107 cycles occurred at 15mm from the loading point，while the maximum fatigue life of 7.31×108 cycles was recorded at 30mm from the loading point， compliant with SAE J1099 standards. Experimental validation confirmed a prediction error of less than 9.2% for the finite element model. The study establishes a quantitative mappng relationship among welding parameters， microstructural properties，and fatigue life， providing a damage tolerance design-based framework for selecting process windows in high-strength steel racingchassisoptimization.

Keywords： AISI 413o; TIG welding;finite element analysis; fatigue life; frame steel tubing

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在当代工程领域，尤其是在汽车运动领域，如中国汽车工程学会巴哈大赛等竞技场合，AISI4130车架钢管的重要性不容小。（剩余5524字）