关键词: 钢板弹簧；承载比；高应力材料；应力集中

Abstract: To address the issue of fractures occurring during the reliability verification process of the composite front suspension leaf spring, this article proposes optimizations to the original design from four perspectives: firstly, enhances the material's ultimate stress by adopting the LQSP1300 material, which elevates the yield strength from 1 100 MPa to 1 300 MPa. Secondly, optimizes the local structure by extending the rear section of the second leaf by 20 mm, alleviating stress concentration when the first leaf is in operation. Thirdly, refines the arc height of the leaf spring, ensuring that under the calibrated height, the leaf spring reverses its load-bearing direction, resulting in a trend of first decreasing and then increasing working stress during the upward jump, thus improving fatigue life. Lastly, optimizes the shot peening process of the leaf spring by applying shot peening to both the upper and lower surfaces, creating a residual stress layer that offsets a portion of the stress during the upward and downward deformation of the leaf spring, further enhancing its fatigue life. Through these four optimizations, the new design has improved its bench fatigue test cycles by 45.4% and successfully passed a 12 000 km road reliability test.

Key words: Leaf spring; Load-bearing ratio; High-stress material; Stress concentration