Experimental and numerical study of hammering process on stress concentration factor for different hole shapes

The stress concentration factor (Kt) in (holes, notch, streamed, etc.) regions of mechanical parts is regarded as a significant and frequent issue that needs to be addressed since raising it in response to large strains and deformations in mechanical elements may fail. The current study examines stress concentration, its factor influence, and various hole shape types using mild steel plates with various hole shapes (circle, triangle, square, and elliptical). A theoretical equation can be used to calculate in (Kt) and all results are practical to kt. The mechanical characteristics and applied tensile stress on a mechanical element. The Auto Desk Inventor program is used to recreate the earlier states, and all of the results follow the same trend, with the triangle hole possessing the highest value (Kt). The Auto desk inventor program is used to simulate the previous states and all results refer to the same trend, where the maximum (Kt) is for a triangle hole (4.8, 7.9), while the minimum is for an ellipse hole whose major axis is perpendicular on longitudinal axis plate (2.26, 1.79, 2.1). The reduction of stress concentration and its factor by using the hammering process on hole edges produces residual stress due to strain hardening in a metal plate. The (Kt) results reduce because of bearing in a circle hole, while compression force on the internal surface of holes (triangle, square, and ellipse). The result in the direction of the hammering process succeeds in producing resist force against the tensile process during the operation of the mechanical element. The stress concentration is increased in a circle hole, the greater the stress concentration to prevent fatigue, avoid abnormalities, and use rounder fillets whenever possible. Surface modification: Because machining leaves behind scratches and grooves, polishing a machined surface will lengthen its fatigue life. Compressive residual stress can be added to the surface layer to extend fatigue life.