The lightweight structure of a semitrailer composite leaf spring is designed and
manufactured using glass fiber composite to replace the conventional steel leaf
spring. The sliding composite mono leaf spring was designed based on the
conventional parabolic spring design theory. The composites product design (CPD)
module of CATIA software is used to create the lamination of the composite leaf
spring. Using finite element analysis of the position and proportion of ±45°
biaxial layer by OptiStruct software, it is found that a certain proportion
(nearly 5%) of a ±45° biaxial layer can effectively reduce the shear stress
under the condition of keeping the total number of layers fixed. Then, the
natural frequency, stiffness, and strength of the composite leaf spring are
simulated by the finite element method. Finally, the stiffness, fatigue, and
matching of the designed spring are tested by experiments. The design weight of
the composite leaf spring is 18.5 kg, which is 55.4% lighter than the
conventional steel leaf spring. The composite mono leaf spring has good fatigue
performance; the vertical fatigue cycles are more than 300,000 times, 1.6 times
of the traditional steel leaf spring. The results of the system bench test show
that the movement state of the composite mono leaf spring is consistent with the
steel leaf spring. It can be preliminarily speculated that the composite leaf
spring structure can meet the requirement of vehicles. A proposed method
combining theoretical analysis, calculation, and finite element simulation can
be used to design and test composite products quickly. This method has a high
significance for the structural optimization of other laminated composite
products.
