Study on the Relationship Between Hardness and Stiffness of Damping Rubber Material

Abstract Damping rubber materials have high elasticity, significant deformation capacity, and excellent damping performance. As the core material of rubber vibration damping products, they are widely used in applications where there is severe vibration and shock. However, during use, these materials are prone to aging reactions, leading to performance degradation and loss of value. Currently, most companies use stiffness as an indicator for evaluating the performance of rubber vibration damping products. However, the measurement process of stiffness is complex and may affect the service life of vibration damping products. Hardness is a key mechanical parameter for rubber materials and is more suitable for evaluating the aging degree of damping rubber materials. This paper selects two materials, NR and NBR, and subdivides them into six samples based on hardness. Under accelerated aging conditions, this paper conducted a 90-day aging experiment. The relationship curves of four parameters with aging time were discovered, including hardness, hardness change rate, stiffness, and stiffness change rate. The study found that the trend of the hardness curve and stiffness curve of the same material with aging time remained consistent. The rate of change in stiffness and hardness gradually decreased within 75 days, and then sharply decreased. At the same time, an equation that describes the relationship between hardness and stiffness is obtained, This provides experimental support for the method of evaluating the aging degree of damping rubber materials based on hardness parameters.