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What is stiffness?

The ability of structures subjected to external forces to resist elastic deformation, called stiffness; Stiffness is often expressed by the force or moment required for unit deformation.

What is the significance of stiffness analysis?

The significance of stiffness analysis is to control structural deformation to prevent vibration, flutter or instability. Static stiffness is generally measured by how much the structure is deformed under static load, while dynamic stiffness is measured by how often the structure vibrates (in practice, the vibration frequency is different and the stiffness is different). If the dynamic force changes very slowly, i.e. the frequency of the dynamic force is much less than the natural frequency of the structure, it can be considered that the dynamic stiffness is basically the same as the static stiffness. Otherwise, the frequency of the dynamic force is much greater than the natural frequency of the structure, the structure deformation is relatively small, the dynamic stiffness is relatively large. However, when the frequency of the dynamic force is similar to the natural frequency of the structure, there is a possibility of resonance, at which point the structure is the most deformed and the stiffest. The dynamic stiffness of metal parts is basically the same as the static stiffness (since the frequency of external forces in general is much less than the inherent frequency of the structure). And rubber parts are generally different, its static stiffness is generally nonlinear. The dynamic stiffness of rubber parts varies with frequency, generally the higher the frequency, the greater the dynamic stiffness. In addition, the dynamic stiffness and the amplitude of the vibration is related to the same frequency, the greater the vibration amplitude and the less the dynamic stiffness.

In the design of suspension isolator, the stiffness is greater when low frequency is required; at high frequencies, the lower the stiffness, the better. Why is this?

First, to withstand the weight of the powertrain and the force from the engine torque, the suspension isolator must have sufficient stiffness. The impact of the road surface and the swing of the engine at startup act on the vibration isolator, these excitation frequency is relatively low. If the stiffness of the isolator is low, the powertrain generates large displacement that may collide with other structures and affect other components placed on the powertrain. Therefore, in the low frequency band, the stiffness of vibration isolator is required. With years of technical experience, Zhong Xiang rubber Co R&D team designed a number of suspension isolators for road and off-road vehicles, greatly improved the feeling of vehicle drivers, CN and EH series popular at road and off road vehicle manufacturers and got very good feedback. We will continue our efforts to provide more cost-effective shock absorption products and technical support to our customers.