Method for Improving the Fatigue Life of a Tubular Stabilizer Bar

Author:  Michael P Binno, Troy, MI
Source:  US Patent 6,418,770 B1
Doc ID:  2002081
Year of Publication:  2002
Abstract:  
An autofrettage process employed on the inner surface of a tubular stabilizer bar. Road shock and other vibrations subject the stabilizer bar to tensile stresses. Tensile stresses cause fractures and decrease the fatigue life of the bar. In employing an autofrettage process, a pressurized fluid is introduced into the interior space of a sealed stabilizer bar, slightly increasing the inner diameter of the stabilizer bar. As the inner surface of the stabilizer bar is deformed, residual compressive stress forces are created which counteract and oppose the tensile stress forces. The residual compressive stress forces prevent the tensile stresses from fracturing the inner surface of the bar, increasing fatigue life. A shot peening process can be employed on the exterior surface of the bar to create residual compressive stress forces which counteract exterior tnesile forces.