Load Identification And Transient Response Analysis Research On Thrust Termination Structure

Spacecraft have to subject harsh dynamics environment in launch phase. The thrustmutation caused by rocket engine ignition and shutdown in the process of the spacecraft willlead to an impact, the impact is difficult to directly measure during launch, besides, stringentweight restrictions and other constraints make impulse response can’t be fully obtained bymeasurement. An important technical means to solve these problems is through a litternumber of measuring points to reverse dynamic loads, as a basis for calculating the forwarddynamics, and ultimately predict the impact response of the entire spacecraft structure.Therefore, this dissertation focuses on the transient response analysis and load identificationof Star-Arrow coupling structure at the time of thrust termination.By analyzing the free running multi-degree system dynamic behavior at the stage ofthrust termination, to observe the relationship among vibration acceleration response andthrust termination time and the system’s natural frequency.The result show that the thrusttermination process shorter or lower frequency of the system, the respone more stronger.With the assume of a linear time invariant, The Green function method is uses to reversedynamic loads of the overall freedom structure. Two response indicate methods of Star-Arrowcoupling structure are built, one of identification methods is based on force load, and the otheridentification methods is based on acceleration load. The convolution relationship betweenabsolute motion acceleration is established, and using a variety of regularization methods tosolve the problem of deconvolution.Combined the ground simulation experiments of thrust termination, the equivalent forceload and equivalent acceleration load are reapplied on the structural model, respectively, andfrom the time domain and shock response spectra to compare the experimental results andresponse predicts results. The result show that the method mentioned in text is validity andaccuracy of response indication. Besides, dynamic load dimension, position of measuringpoints and local stiffness have influence on the accuracy of the analysis.Using MATLAB GUI design featurs develop visualization interface for engineeringapplication. This interface include data preparation module, the response read module,thekernel read module, regularization method module, load identification module, and help filesmodules.it also integrate related software of transient response field analysis.