Strength calculation of air spring

The air spring produced by Songxia shock absorber is an excellent vibration isolation element. It has the advantages of low natural frequency, good damping performance, high vibration and sound insulation, and is widely used in vibration and noise reduction of power machinery. The pressure in the air spring bag is generally large, because its load is large, and the gauge pressure can reach more than 1 MPa. Generally, air curtain capsules are made of multi-layer curtain rubber laid at a certain angle. The curtain rubber is based on rubber, and the curtain is a reinforced composite material, which can bear a large load. When the air pressure is high, the multi-layer curtain rubber can be laid symmetrically to meet the strength requirements. The strength of air curtain film is analyzed by finite element method, and its stress state is calculated, and then the strength theory is used to judge whether it has reached the stress limit, so as to analyze its strength.

when establishing the curtain rubber coordinate axis, it is assumed that the stress component in the normal direction is smaller than that in the LT plane, which can be ignored. The analysis of single-layer cord rubber is simplified as a two-dimensional generalized plane stress problem, and the stress-strain relationship of single-layer cord rubber is obtained. Under the plane stress state, it has five basic strengths: longitudinal tensile strength FLt, longitudinal tensile strength FLc, transverse tensile strength FTt and longitudinal shear strength FLT. For curtain rubber material, the theory of judging its failure strength is more suitable for specification, which extends the yield condition of isotropic material to orthotropic body, making it suitable for different tensile and compressive strengths and conforming to the characteristics of curtain rubber.

The gas bomb is an anisotropic shell, and it is difficult to analyze it with the classical bomb theory because of the complex boundary conditions. Therefore, it is a simple and feasible method to analyze the capsule by finite element method. In addition, most finite element software also provides laminated material elements. Taking the gas cartridge case as an orthotropic shell, the shell element is used to analyze it, and the shell element is used to calculate the stress of each layer, so as to calculate the stress of each layer and the strength. The simulation and nonlinear factors of rubber materials are analyzed, mainly considering two aspects. Harpingtsai equation is often used to calculate the principal engineering constants of composites. However, when using this equation to calculate the shear modulus and Poisson's ratio, it is necessary to know the shear modulus and Poisson's ratio of matrix phase and reinforcement material. These two parameters of cord material are difficult to be obtained through experiments, and the cord is combined with rubber in the form of addition, which makes the calculation method of its mechanical parameters more complicated.

The material properties of composite materials are specially modeled by using the finite element analysis software i-deas. Methods: According to the above results, the properties of orthotropic single-layer materials are generated, and then the single-layer materials are paved according to a certain angle and paving rules to form layered materials, and then they are applied to the finite element model.