Structural Design and Analysis of Sliding Composite Mono Leaf Spring

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.