Overall Technical Research On Forest Fire Extinguishing Bombs Applied To Unmanned Aerial Vehicle

Forest fire protection work is a disaster relief nature,related to ecological safety and people's lives and property.After the forest fires occur,the people's safety and fire remote control are still a worldwide problem.As a remote fire extinguishing tool,fire extinguishing bombs play a pivotal role in forest fire prevention.As a carrier platform,UAV has a widely application in military and civilian fields.Based on the characteristic of UAV,Forest Fire Extinguishing Bombs Applied to UAV can take advantage of the features of UAV platform and improve the security of extinguishing without the limitation of place.The subject studies overall technical of forest fire extinguishing bombs applied to UAV,including the overall plan of forest fire extinguishing bombs,projectile structure,balance device,emission characteristics,internal-external ballistic characteristics and dispersion characteristics of extinguishing agents.The dynamics and kinematics simulation results provide foundation for research and engineering application of forest fire extinguishing bombs applied to UAV.The main research contents are as follows:(1)Combining the application status at home and abroad of forest fire extinguishing bombs and the working characteristics of UAV,the overall structural scheme of forest fire extinguishing bombs applied to UAV that adopts balanced emission structural technology is proposed.The preliminary analysis and design of projectile structure and balance device are also carried out.(2)Analyzing and calculating the emission intensity of balance device and complete the structure design.At the same time,transient dynamics of the projectile simulation is conducted by Workbench software,and the stress and strain curves of the projectile are obtained.The simulation results show that projectile emission intensity meets demand.(3)Using Simulink software to simulate the launching process of the forest fire-fighting projectile,and the motion law of the projectile and balance device was obtained.Analysising the internal motion of the forest fire extinguisher for drones,and established the pressure distribution model of the launching of the raft.Combined with the test results,the performance of the UAV carrier platform can be required to ensure that the carrier platform meets the needs of balanced launch.(4)Simulating the external ballistic of projectiles with Matlab software,the curve of projectile displacement with time and the centroid velocity of the projectile with time,the results show that the fly displacement of projectiles meets the fire safety distance.(5)Using TrueGrid software to establish the finite element model and the nonlinear explicit dynamics software LS-DYNA to calculate the numerical solution,which was used to simulate the explosion and scatters process of the projectile under different dynamite filling modes,and select the central column filling bomb structure.Then,simulating the explosion process of the projectile under different specific dose conditions,and analyzing the fire-extinguishing agent's movement state according to the motion state of the fire-extinguishing agent particles and the corresponding empirical formula.The results showed that the shell of the forest fire extinguishing projectile was evenly split when the specific dose was 3.21 percent,and the fire extinguishing agent is evenly dispersed,and the effective fire extinguishing area is 9 square meters which was consistent with the test results.