Numerical And Experimental Study On Weak Confinement Static Test Of Solid Rocket Motor

At present,in the development stage of solid rocket motor,everything is normal in ground test,but unstable combustion occurs when working at high altitude,which means that only by improving the existing test mode can it better meet the requirements of model development.The research content of this paper aimed at the above problems is as follows:1.This paper establishes missile and solid rocket motor models based on common engineering background.The model of long-range air defense missile with large aspect ratio and solid rocket motor is designed with reference to foreign models.The stress state of the missile engine when working at high altitude is calculated,and then the modal characteristics of the engine when working at high altitude are obtained.2.The numerical model of the ground test of the engine under various constraints is established,and the modal characteristics of each constraint mode are calculated,and the mode shape and frequency of the engine under high altitude are compared,and the ground weak constraint test mode closest to the high-altitude working state is obtained.3.The aerodynamic impact load on the engine of the missile carrier at different ballistic positions is calculated.By applying it to the ground test of the engine with different constraints,the influence of the constraint mode on the impact load response of the engine is obtained,and the mechanical characteristics of the engine under weak constraints are calculated,which proves its superiority over the traditional test bench.4.The ground cold flow shrinkage model of solid rocket motor was designed and fabricated,and the ground cold flow test stand with weak constraint was built.The vibration modal characteristics of engine shrinkage model are calculated and analyzed.On this basis,the constraint mode of cold flow test model is changed to carry out modal test and cold flow test.It is proved that the weaker the restraint mode is,the lower the frequency of the same mode shape of the engine will be.The tail spring suspension does not change the mode of the engine.The constraint mode of the head fixed tail spring suspension not only ensures the safety of the test but also retains the freedom of the engine tail.Cold flow test proves the safety and feasibility of engine static test with weak constraint.