Dynamic Modeling And Simulisionanalysys Of Iternally Carried Air-launched

Internally carried air-launch of the heavy rocket was selected instead of ground launch for the following reasons:(1) capability to carry heavy payload mass,(2) fewer restrictions and improved safety of air launch by avoiding flight over occupied land,(3) reduced cost of ground launch support operations achieved through decreased infrastructure. Therefore, this technology has many advantages in civil aspect and military aspect. In this paper, an air-launch project will be introduced and air drop analysis will be studied.First,the air-launch system was introduced in system composition and the types of air launch methods. Three stages of air drop methods were studied during this system. Equations of motion and the restraint relations of this progress was studied. The rocket coordinate system was defined. The atmospheric model for air-launch simulation was described. Aerodynamic force composition and various Euler angles relations were studied. These studies provide the theory instruction for the following model refinement.Second, the models of the air-launch system, like parachute model, the transporter with tires for cushion, aerodynamics model and so on, were all studied and were built. The parachute model was build based on Kirchhoff equation. The characteristics of many types parachutes were conceded. The series of parameters were used to characterize the parachute dynamics model. The tire model in the transporter was characterized with stiffness and damping parameters. Computational fluid dynamics(CFD) was completed to evaluate the aerodynamic characteristics during the drop. The data from the aerodynamic analysis was used in the air launch simulation discussed above.The 3D air-launch system model was established for the simulation of the air drop with the restraint module and the expansion module using ADAMS software. In this model, restraint relations were defined for every model who contact with others. The restraint relations and revolving relations of tires were studied. The contact restraint relations of the transporter were characterized. the launch vehicle aerodynamic force and the chute model aerodynamic force base on Kirchhoff equation was realized using three dimensional strength model and the three dimensional moment of force model in ADAMS software.Finally, the dynamics characteristics of the rocket, the chute and the tire were studied using air-launch system dynamic simulation model. Many tests were conducted with different diameter ring slot parachute to determine the ideal state of the launch vehicle. The position of launch vehicle and the trajectories for the key points on the launch vehicle were studied. The Behavior and the force of the parachute and thread were simulated. And the force of the tires in the transporter studied.The 3D air-launch system model shows that Gravity Air Launch method works as intended. This analysis method promises to contribute to improving the simplicity, safety, cost, and reliability air launching project. The analysis program met the technology objectives successfully.