平方阻尼在冲击隔离中的特性与作用研究

Effect of quadratic damping in a shock isolation system

传统的抗冲击设计认为阻尼对瞬时冲击的最大结构响应没有显著影响,因此在冲击隔离中,忽略阻尼效应,重点考虑选择合适的刚度。但实际应用研究表明,这类系统不能同时抑制相对位移幅值和绝对加速度幅值,无法满足船舶及其设备的抗冲击要求。针对这类问题,建立单自由度平方阻尼抗冲击系统模型,研究平方阻尼在冲击隔离系统中的特性和作用,结果表明:平方阻尼可以明显提升系统的冲击隔离效率,降低相对位移幅值;同等冲击条件下,含平方阻尼系统绝对加速度冲击响应幅值比线性阻尼系统响应幅值小;阶跃速度等效法不适宜计算平方阻尼冲击隔离系统的绝对加速度,但可以计算其相对位移。

It is considered that damping has not significant effect on structure’s maximum response when the structure is suffered from a short time shock in the conventional shock isolation design. Therefore, a traditional shock isolation system is often designed on the selection of appropriate stiffness and ignoring the damping effect, which could not restrain both the absolute acceleration maximum and the relative displacement amplitude at the same time. This shock isolation system could not meet the shock isolation requirements of ships. A single-degree-of freedom quadratic damping shock isolation system model is built here. Effect of quadratic damping in a shock isolation system is studied by numerical simulations. It is indicated that using quadratic damping can obviously improve its shock isolation performance and reduce the relative displacement amplitude. Quadratic damping shock isolation system can obtain smaller response amplitude than linear damping system under the identical shock conditions. Velocity step equivalent method is not suitable for the calculation of absolute acceleration shock isolation system, but it can calculate the relative displacement.