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A B S T R A C T The paper deals with the fatigue and failure analysis of serial shot-peened leaf springs of heavy trucks emphasizing on the influence of thermal treatment and shot peening on fatigue life. Experimental stress-life curves are determined by investigating smooth specimens subjected to fully reversed rotating bending conditions. These test results are compared to corresponding ones determined from cyclic three-point bend tests on shotpeened serial leaf springs in order to reveal the influence of the applied thermal treatment and shot peening process on the fatigue life of the high-strength steel used for leaf spring manufacturing, dependent on the load level. Microstructure, macro-and micro-hardness analyses are performed to support the analyses and explain the effects resulting from the certain shot peening process on the surface properties of the high-strength spring steel under investigation. The assessment of the fatigue results reveals nearly no life improvement due to the manufacturing, emphasizing the necessity for mutual adjustment of shot peening and thermal treatment parameters to take account for life improvement. D = diameter E = Young's modulus f 1 , f 2 = fatigue endurance strength correction factors K = slope of the stress-life curve HB = Brinell hardness M σ = mean stress sensitivity factor N f = number of cycles till specimen rupture R = stress ratio R = radius R m = ultimate tensile strength R z = mean roughness depth σ a = stress amplitude σ E,a = endurance stress amplitude σ m = mean stress I N T R O D U C T I O NHigh-strength steels are used in various technological fields, particularly in the industry of spring manufacturing. Especially in the automotive industry, leaf springs constitute the most effective suspension way of commerCorrespondence: G. Savaidis.

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PurposeThe purpose of this paper is to develop a FE based modeling procedure for describing the mechanical behavior of high‐performance leaf springs made of high‐strength steels under damaging driving manoeuvres.Design/methodology/approachThe type and number of finite elements over the thickness of leaves, as well as the definition of contact, friction and clamping conditions, have been investigated to describe the mechanical behavior in an accurate and time‐effective manner. The proposed modeling procedure is applied on a multi‐leaf spring providing complex geometry and kinematics during operation. The calculation accuracy is verified based on experimental stress results.FindingsA FE based modeling procedure is developed to describe the kinematics and mechanical behavior of high‐performance leaf springs subjected till up to extreme driving loads. Comparison of numerically determined stress distributions with corresponding experimental results for a serial front axle multi‐leaf spring providing complex geometry and subjected to vertical and braking loads confirms high calculation accuracy.Research limitations/implicationsThe proposed FE based model is restricted to linear elastic material behavior, which is, however, reasonable for the high‐strength steels used for leaf spring applications.Practical implicationsThe proposed FE procedure can be applied for the design and optimization of automotive leaf springs, especially for trucks.Originality/valueThe proposed procedure is simple and can be applied in a very early design stage. It is able to describe accurately the leaf behavior, especially the stiffness and stress response under the most significant driving events. It goes far beyond today's practice for leaf spring design, which is based on analytical methods not covering complex axle and steering kinematics, large deformations and non‐linearities.

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