Research Of Structural Integritity For A Certain Solid Rocket Motor Grain

Structural integrity analysis of grain is a critical problem for the designers andmanufacturers of Solid Rocket Motor (SRM). For the requirement of high range andquick maneuver, finocyl grains are usually used in the new anti-aircraft missile becauseof its hith volumetric loading fraction, which will lead to poor structural intergrity dueto its high structural response. The structural integrity of SRM has become one of themost crucial problem for the new tactical missile motor.To solve the problem of explosion during the ignition exepriment at lowtemperature, numerical simulations and experiments on the structural integrity for theSRM grain are investigated.Structural integrity criterions of SRM are ascertained according to the differentmaterials of the SRM. Moreover, SRM structural integrity analysis method and generalprocesses using CAE software are summarized. The research work provides thefoundation for structural analysis and integrity assessment of SRM.The structural integrity analysis is completed for the original SRM grain using3Dviscoelastic finite element method(FEM). According to the geometric configuration ofthe original SRM, its FEM model is established. The parameters of the Burgers model isderived based on the data fitting of the relaxation modulus by the method of leastsquares. The stress and strain field of the grain in the processes of curing, lowtemperature experiment, and ignition experiment at hith, normal and low temperature,respectively. The maximum Von Mises strain criterions is employed to assess thestructural integrity of the grain. The results show that the structural integrity of theoriginal SRM grain in the ignition experiment at low temperature cannot meet therequirement.Grain shape improvement of the original SRM grain is completed based on thestructural integrity analysis. The effects of the crucial geometric parameter and thecuring temperature on the SRM grain in the ignition experiment at low temperature areanalyzed. Grain shape improvement method of the original SRM is proposed. Theresults show that Grain shape improvement of the original SRM decreases its maximumVon Mises strain, and increase its safety factor.Ignition experiment at low temperature of the SRM is performed, and the solutionmethod is proposed based on its failure reason analysis. According to the analysis of thefailure reason in depth, it is concluded that the latter curing of the propellant results inthe explosion of the improved SRM. In the end, the problem is solved by improving thecuring technology of the propellant.The achievements obtained in this dissertation make an important role on thefailure locating, theoretical analysis, failure capturing of SRM explosion during the ignition exepriment at low temperature. The failure of SRM ignition at low temperaturehas been solved successfully. The methods and conclusions would be available for thedesigners, manufacturers of other SRM.