建立了发泡聚乙烯缓冲包装系统的缓冲模型，运用四阶变步长Runge-Kutta方法，计算出了此非线性系统在半正弦脉冲冲击下的冲击响应谱，并讨论了参数λ-1,λ-2和λ-3对冲击谱的影响规律。

Cushioning model of two degrees of freedom for expanded polyethylene cushioning packaging system was established. The shock response spectrum of the nonlinear system under the action of half-sine pulse was calculated using Runge-Kutta method. The influencing rule of parameter λ-1,λ-2, and λ-3 on shock response spectrum was discussed.