运输包装随机振动的加速度响应谱分析

Acceleration spectrum analysis for transport packaging under random vibration

正切型运输包装系统的加速度随机振动响应谱理论尚未进行系统研究,然而产品加速度响应是评价产品包装有效性的关键指标,而且很大一部分包装材料在一定变形范围内符合正切型的力-位移关系。将考虑关键部件的运输包装随机振动模型化为两自由度正切型包装系统,建立了系统的加速度响应谱求解方法,讨论了所提方法的适用范围,并采用数值模拟验证了所提方法的有效性。在此基础上,进一步探究了加速度响应谱对于外激强度和系统参数的敏感性,分析了正切型系统的硬弹簧非线性效应。随着激励水平提高,由于正切型刚度“硬弹簧”非线性作用,从而使产品主体的一阶响应峰值点频率及关键件一阶、二阶响应峰值点频率向右偏移逐渐增大;存在一个最佳的系统非线性特征参数β*,使关键件的一阶响应峰值或响应总体能量最小;系统的阻尼比、频率比、关键部件与产品的质量比对响应起着十分明显的“多阶调频调节带宽”作用。所提方法不仅能够有效地预测产品主体和关键件的响应,也为包装优化设计提供理论依据。

It has not been systematically studied on the theory for acceleration response spectrum of tangential transport packaging systems under random vibration,but acceleration response is a key index to evaluate the effectiveness of product packaging.In addition,a large proportion of packaging materials conform to tangent type of force-displacement relationships within a certain deformation range.Thus,the transport package considering critical component under random vibration was modeled as two degrees of freedom tangential packaging system,and the approximate solution method of the acceleration response spectrum was established.Meanwhile,the application scope of the proposed method was pointed out.Numerical simulation was carried out to validate the method.On this basis,the sensitivity of the acceleration response spectrum to external excitation intensity and system parameters was explored further,and the nonlinear effect of tangential hard spring was also analyzed.Due to the effect of the“hard spring”of tangent system stiffness,the frequency at the first-order resonance peak point of the product body and the first-order and second-order resonance peak points of the critical component acceleration responses were increasing to the right.There exists an optimal nonlinear characteristic parameterβ,which can minimize the first-order response peak or the overall response energy of the critical component.System damping ratio,frequency ratio,critical component and product quality ratio play a very obvious“multiple order frequency modulation to adjust bandwidth”role on the response.The proposed method can not only effectively predict the response of product body and critical part,but also provide a theoretical basis for the packaging optimal design.