In this paper，the vibration of the vehicle suspended with oil-pneumatic springs is investigated, simplified as a two-degree non-linear system subjected to a stationary random road excitation. The MSRs of the displacement，velocity and acceleration of the vehicle vibration are given. The approach of selecting oil-pneumatic spring parameters is proposed.
This paper discusses a similarity method in the perforation of the projectile into a target. First of all, various physical quantities and similarity parameters which determine the process of the perforation are analysed. Then on the basis of the analysis geometrical similarity law is discussed and verified for both of blunt-nose-projectile and long-rod-projectile.
The solubilities of concentrate solution system composed of No. 3 nitrocellulose (NC) with dietyl phthalate (DEP)，dibutyl phthalate (DBP) and glycerin triacetate(TA)have been studied in this paper. From the results of these experiments it is concluded that the order of their solubility is NC-DEP＞NC-TA＞NC-DBP. The solubilities of concentrate solution system of NC-DEP increase with the increase of its solvent ratio. The solubility of NC-mixed solvent system is better than that of NC-mono-sol- vent system. These results have some reference for designing and processing powders。
Based on the stability concept of the non-linear theory of elasticity, this paper derived the formula of critical load for the buckling of rectangular plates simply supported on all four sides under the action of unequal uniform loading in two mutually perpendicular directions. The special case of the formula under the action of uniform loading only in one direction is emphatically investigated， and the relevant approximate formula convenient for applying to engineering practice is obtained. Moreover， the comparison with the corresponding solution in the classical theory of thin plates and the analysis for several numerical value calculated are also discussed.
In this paper, non-linear motion of finned projectile with small damp and weak non-linear static moment has been studied. Using the stable limit cycle，it has been explained that some finned projectiles probably produce self—oscillation. Using the unstable limit cycle，the causes of the fortuitous fall of some finned projectiles have been discussed. In order to decrease the influence of the self-oscilation and eliminate the fortuitous fall of the finned projectile? the non-linear part of the damping moment and lift must be inc— reased，and the non-linear part of the drag must be decreased.
