| Compared with the traditional metal spring,the composites suspension spring has the advantages of light weight,corrosion resistance and fatigue performance,and it has great application prospect in the current trend of automobile lightening.In this paper,the composites suspension spring was studied by finite element method and experimental method.The main contents and conclusions of this paper were shown as following:(1)The elastic mechanics of the composites was analyzed,and the elastic constants calculation formulas of the unidirectional composites and the orthogonal fabric composites was given.Calculation formula of the composites suspension spring stiffness was also given.Established the geometric model and finite element model of the composites suspension spring who had fiber fabric reinforcement and TPU core.(2)Analyzed section shear stress,interlaminar shear stress and layer stress of the composites suspension spring,and judged the possible failure position of the spring by the finite element method.Proposed the finite element analysis method for stiffness and strength of composite suspension spring.(3)Made simulation analysis of the composites suspension springs with different fiber volume fractions,different TPU core diameters,different ply angles,different fiber types and hybrid fibers.The results shown: 1.The stiffness of spring increased linearly with the increase of fiber volume fraction.As the fiber volume fraction increased,the spring stiffness to weight ratio(p/m)increased,so the spring got a higher utilization of composites material.2.Maintaining the spring wire diameter of 9.3mm,the composites suspension spring with or without TPU core has same spring stiffness,but spring with TPU core had higher strength than spring without TPU core.When the diameter of TPU core changed in the range of1mm-3mm,the stiffness and strength of the spring had no significant change.When the TPU core diameter increased to 5mm,the stiffness and strength of the spring was obviously decreased.The spring with TPU core diameter of 4mm had the largest stiffness weight ratio(p/m).3.As the ply angle increased from 0° to 45°,the stiffness and strength of spring increased.4.With the same ply angle of 45°,the spring stiffness of T300 carbon fiber spring was much larger than basalt fiber spring and S2 glass fiber spring,but T300 carbon fiber spring occured compression instability.Reducing the ply angle to 32°,the compression instability of T300 carbon fiber spring disappeared.Compared with T300 carbon fiber spring and S2 glass fiber spring,basalt fiber spring had the best comprehensive performance.5.T300 carbon fiber-Basalt fiber hybrid spring combined the advantages of T300 carbon fiber spring and basalt fiber spring was the ideal form of the composites suspension spring.(4)Fabricated the composites suspension springs reinforced by continuous basalt fiber cloth and TPU core.Springs compression test showing: 1.The compressive load and displacement of the the composites suspension spring was approximately linearly related.Compared with the simulation calculation value,the experimental value of spring stiffness was bigger with an error less than 10%.2.The spring with fiber volume fraction of 40% had a greater stiffness than the spring with fiber volume fraction of 30%,and the stiffness of spring with ply angle of 45° was much greater than spring with ply angle of 0°.3.Consistent with the simulation results,the spring samples did not exhibit failure when compressed from free state to solid state.4.After the first and second compression,the spring free height and spring stiffness decreased in different degrees,but with the increase of the compression number,the spring free height and stiffness tended to be stable. |
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