P.J. Prause Durotec GmbH

S-Ply® leaf springs consist of layered UD (Unidirectional) prepreg plies pressed together. By orienting individual prepreg plies relative to each other, the mechanical properties of an S-Ply® leaf spring can be adapted to the relevant customer requirements and applications during manufacture. S-Ply® leaf springs offer superior properties compared to steel leaf springs in many applications

Material properties

Unidirectional fibers

The reinforcing fibers present in the leaf springs consist of strictly parallel-oriented glass or carbon fibers that are not interwoven. The fibers are not prestretched or kinked.

to metallic materials with an isotropic structure, they are directionally oriented and can therefore be aligned to form a material-specific design

Epoxy resin matrix

Epoxy resin systems serve as binders. Their special coordination ensures very good adhesion to the glass surface, resulting in optimum dynamic and electrical properties. The ratio of matrix resin and reinforcing fibers is selected in such a way that all the advantages of the selected raw materials are optimally utilized as a composite material.

The matrix performs a number of important tasks. It fixes the fibers in the desired arrangement and supports them against buckling under compressive stress. In addition, it has a force-bearing function and thus transmits the forces that occur to the fibers.

this way, the polymer matrix exerts a decisive influence on the toughness and damage tolerance of the composites

Tested long-term strength

The long-term strength of S-Ply leaf springs was tested by IMA Materialforschung und Anwendungstechnik in Dresden in a Wöhler test. The resulting Wöhler curve indicates, as a function of the deflection voltage, the number of load cycles that can be tolerated until the expected fatigue failure. From a load cycle of 108 oscillation cycles, fatigue strength is assumed.

• Balanced spring behavior, significantly greater specific spring effect, higher internal damping, 6 times greater elastic energy storage capacity compared with spring steel.

• The mechanical strength of the component, especially against torsion, can be precisely controlled. Ideal adaptation of leaf spring geometry and material to the load.

• Enables mechanically and dynamically highly stressable designs

S-Ply®: Scotchply, thought through further

Scotchply™ fiber composite, developed and patented by 3M in 1954, has been processed into high-performance leaf springs by Prause Durotec since 1974. Today, leaf springs made of the optimized fiber composite material are produced and sold worldwide by Prause Durotec under the trademarked product name S-Ply®.