Structural Design On Non-linear Rubber Suspension For Heavy-duty Trucks

NVH control technology and lightening design technology is a development direction of modern automobile design technology. Rubber suspension and air suspension are important suspension products used for realizing such technical concept. Rubber suspension provides nonlinear load bearing and vibration isolation by a pair of rubber springs consisting of a shearing main rubber spring and a compression auxiliary rubber spring. Therefore capability and life of vibration isolation are key points of design technology of rubber suspension, including variable-stiffness, equifrequency and vibration isolation design, fatigue and reliability design of rubber suspension system.Basis material parameters are designed on the basis of hyperelastic large-strain behavior, dynamic behavior under time domain or frequency domain and creepage and fatigue behavior for characterizing rubber suspension material. A hyperelastic strain energy density surface 3D model diagragm is established, on the basis of basic data by uniaxial, biaxial and planar tension tests. Furthermore, a rubber-material full-life fatigue H diagram is created by taking FCG(Fatigue Crack Growth)as basic tests and by taking Thomas model and Mars-Fatemi model as crack extension models.By using a hyperelastic model and a lag model, certain a rubber suspension is simulated to gain nonlinear load-displacement curve. The practical equifrequency area of the rubber suspension is gained by contrasting ideal equifrequency curve, and transverse stability behavior fitting to test is predicted by hyperelastic and Mullins model. The rubber suspension in the research has excellent transverse bearing capability and stability and equifrequency area not changing with load, and has the weight successful lightened by 600 kg compared with flat spring suspension.A vibration-isolation characteristic equation of rubber suspension of paraellel hydraulic damper is established, furthermore a rubber suspension vibration-isolation model illustrating temperature effect is built by temperature scanning test data of rubber material, thus gaining the transfer characteristic curve for characterizing vibration isolation capablity of rubber suspensino. Meanwhile, vibration isolation characterization comparison tests under empty load and full load of rubber suspension are carried out, and key test data characterizing vibration isolation capability of rubber suspension is gained so as to validate the feasiblity of design.Equivalent fatigue analysis and test validation of rubber suspension product are done on the basis of 200 thousand kilometers, and a fatigue design diagram is established on the basis of allowable maximum overload capacity. Meanwhile, road test of rubber suspension is carried out so as to gain design information such as dynamic creepage amount, stiffness loss rate and change rate of vibration isolation performance, etc. The practical fatigue performance of product is validated by data analysis.The design technology of rubber suspension in the research can be used as reference for research and design of rubber suspension.