Fixture device suitable for fatigue test of welding head of T-shaped test piece and failure mode evaluation method

The invention discloses a fixture device suitable for a fatigue test of a T-shaped test piece welding head and a failure mode evaluation method, and relates to the technical field of the fatigue test of the T-shaped test piece welding head. The invention aims to solve the problems that in a traditional fatigue test, a T-shaped joint needs to be clamped and fixed by punching a test piece, and an existing clamp can only clamp T-shaped joints of the same size. A symmetrical simplified model is adopted to perform a simulated fatigue tensile test on a T-shaped test piece 4, stress distribution of all parts on the T-shaped test piece 4 is obtained through a stress nephogram simulated by a finite element, the position where failure easily occurs is obtained through structural mechanical analysis, and the position where the stress is large is the position where failure easily occurs; according to a structural stress method formula, the node force of the position where failure is prone to happening is calculated. The