摘要
本文讨论平方阻尼(以参数a表征)在图(1)所示的缓冲系统中的作用,结果表明:平方阻尼对于降低相对位移峰值d_m总有良好的效果,但不一定降低加速度峰值a_m。在一定速度冲击V下,系统的平方阻尼有两种最佳值,使a_m最小的a_(am)和使缓冲效率γ最高的a_(cm),而平方阻尼最佳条件依赖于系统的缓冲弹簧的刚度变化类型: (1)线性弹簧情况:a_(am)=a_(cm),最佳条件为系统在首程中均匀减速; (2)渐硬弹簧情况:a_(am)=a_(cm),最佳条件为系统在首程中初始和终末加速度相等即; aV^2=ω_0~2q(dm) (3)渐软弹簧情况:a_(cm)>a_(am)。 本文的基础是所谓“首程显峰”,假定即系统在速度冲击V下的响应峰值d_m和a_m出现在第一行程中。当平方阻尼值不太小,缓冲弹簧刚度特性接近反对称时,该假定成立。
In this paper we discuss the role of quadratic damping (QD) in the shock-isolation system as shown in Fig. 1. It is shown that QD always causes a decrease in peak value dm of the relative displacement, but not in that of acceleration. For a given shock, there exist two kinds of optimal QD: the damping αam that minimizes the peak value am of acceleration and the damping αam that maximizes the shock isolation efficiency γ. The optimal conditions for αam and αcm depend on the type of the spring in the system.(1) QDLSS (a system with linear spring). αam=αem Their optimal conditions are the uniformity of acceleration in the first stroke of the system motion.(2) QDHSS (a system with hardened Spring).αam =αem Their optimal conditions are the equality of the initial and final accelerations in the first stroke. (3) QDSSS (asystem with softened spring). αam<αam, Throughout this paper,we assume that the peak values of response occur on the first stroke of the system motion. On the basis of this hypothesis, the following relations:can be derived, whereThis hypothesis simplifies the analysis of the problem considerably It holds when the property of the spring in the system is nearly skew symmetrical and QD is not too small.
关键词
缓冲系统
非线性
平方阻尼
隔冲击
shock insulation, non-linear damping, non-linear vibration, quadratic damping, peak values of response, shock-isolation efficiency
