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Chen A.-J.,Jiangnan University | Chen A.-J.,China National Control and Test Center for Packaging Quality
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2013

The variational iteration method was used to give an approximate solution to dropping shock problem of a cubic nonlinear packaging system. In order to raise the accuracy of the solution, a novel method combining the variational iteration method with the energy method was proposed. Using it, the maximum dropping shock response acceleration and displacement of the system were solved with the energy method, and the first-order iteration approximation solution was modified. The results show that the acceleration versus time and the displacement versus time curves obtained with this method are very similar to those using the elliptic integration method, and the accuracy of acceleration peak value and extended period of dropping shock obtained is satisfactory. The studying results provided a new method for dropping shock problem analysis of nonlinear packaging systems.


Duan N.,Jiangnan University | Hao M.,Jiangnan University | Chen A.,Jiangnan University | Chen A.,China National Control and Test Center for Packaging Quality
Mathematical Problems in Engineering | Year: 2015

Dimensionless nonlinear dynamical equations of a tilted support spring nonlinear packaging system with critical components were obtained under a rectangular pulse. To evaluate the damage characteristics of shocks to packaged products with critical components, a concept of the damage boundary surface was presented and applied to a titled support spring system, with the dimensionless critical acceleration of the system, the dimensionless critical velocity, and the frequency parameter ratio of the system taken as the three basic parameters. Based on the numerical results, the effects of the frequency parameter ratio, the mass ratio, the dimensionless peak pulse acceleration, the angle of the system, and the damping ratio on the damage boundary surface of critical components were discussed. It was demonstrated that with the increase of the frequency parameter ratio, the decrease of the angle, and/or the increase of the mass ratio, the safety zone of critical components can be broadened, and increasing the dimensionless peak pulse acceleration or the damping ratio may lead to a decrease of the damage zone for critical components. The results may lead to a thorough understanding of the design principles for the tilted support spring nonlinear system. © 2015 Ningning Duan et al.


Wang L.,Jiangnan University | Chen A.-J.,Jiangnan University | Chen A.-J.,China National Control and Test Center for Packaging Quality
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2012

The geometric nonlinear dimensionless dynamic equations of a suspension spring system were developed under action of a rectangular pulse, and the numerical analysis of its shock characteristics were conducted using Runge-Kutta method. A new concept of three-dimensional shock response spectra was presented, the ratio of the maximum shock response acceleration of the system to the peak pulse acceleration, the pulse duration and the suspension angle of the system were three basic variables of the three-dimensional shock response spectra. Based on the numerical results, the effects of the suspension angle and the damping ratio of the system on the shock spectra were discussed. It was shown that the effects of the suspension angle and the damping ratio of the system are particularly noticeable, increase in damping can obviously decrease the maximum shock response acceleration of the system. The proposed method provided a reference for design of a shock absorber with a suspension spring system.


Dong Z.-H.,Jiangnan University | Lu L.-X.,Jiangnan University | Lu L.-X.,China National Control and Test Center for Packaging Quality | Liu Z.-G.,Jiangnan University | Liu Z.-G.,China National Control and Test Center for Packaging Quality
Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis | Year: 2012

The direct determination method of heavy metals, Pb, Cd, Cr, Co, Ni, Zn, As and Sb in food packaging ceramics was studied by using inductive coupled plasma mass spectrometry (ICP-MS). Factors influencing the determination were also studied in detail. By choosing the optional operating parameters and appropriate isotopes of the element to be detected, the influence of mass spectrometry interference was conquered effectively. The detection limits were 0.023 μg·L-1 for Pb, 0.004 μg·L-1 for Cd, 0.030 μg·L-1 for Cr, 0.025 μg·L-1 for Ni, 0.012 μg·L-1 for Sb, 0.180 μg·L-1 for Zn, 0.017 μg·L-1 for As, and 0.002 μg·L-1 for Co. The recovery rates of the method were between 95.8% and 104.4%. The RSDs were between 1.1% and 3.3%. The method was simple, rapid, precise, convenient and suitable for daily inspection of import and export ceramic ware.


Duan N.,Jiangnan University | Song S.,Jiangnan University | Chen A.,Jiangnan University | Chen A.,China National Control and Test Center for Packaging Quality
Mathematical Problems in Engineering | Year: 2014

Dimensionless nonlinear dynamical equations of a tilted support spring nonlinear system with critical components were obtained under the action of a rectangular pulse, and the numerical results of the shock response were studied using Runge-Kutta method. To evaluate the dynamic characteristics of critical components, a new concept of three-dimensional shock response spectra was proposed, where the ratio of the maximum shock response acceleration of critical components to the peak pulse acceleration, the pulse duration, and the frequency ratio were three basic parameters of three-dimensional shock response spectra. Based on the numerical results, the effects of the angle, the peak pulse acceleration, the mass ratio, the frequency ratio, and the pulse duration on the shock response spectra were discussed. © 2014 Ningning Duan et al.


Chen A.-J.,Jiangnan University | Chen A.-J.,China National Control and Test Center for Packaging Quality
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2010

The nonlinear dynamical equations of a tilted support spring system were obtained under action of a rectangular pulse, and the numerical results of the shock response were studied using Runge-Kutta method. To evaluate the shock characteristics of the tilted support spring, a new concept of three-dimensional shock response spectra was proposed, the ratio of the maximum shock response acceleration of the system to the peak pulse acceleration, the pulse duration and the angle of the tilted support spring were three basic parameters of the three-dimensional shock response spectra. Based on the numerical results, the effects of the peak pulse acceleration and damping ratio on the shock response were discussed. It was shown that the effects of the peak pulse acceleration, the angle of the tilted support spring and the damping ratio of the system are particularly noticeable, the damping can obviously decrease the maximum shock response acceleration of the system. The proposed method provided an academic foundation for design of shock absorber with tilted support spring.

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