Structural Analysis Of Solid Rocket Motor Test Frame And Its Realization By

Test frame is the main equipment for Solid Rocket Motor(SRM) ground ignition test, it is directly involved in the thrust, attitude control, transient thrust and negative thrust measurement. The test frame carries the full weight of the SRM and its accessories, which gives the SRM necessary limit or positioning and transfers engine thrust in the ignition test. Its structure has direct influence on the safety and reliability of SRM performance and the accuracy of thrust measurement. Therefore, the performance analysis of the test frame is an important part of SRM test research.In this paper, taking a test frame structure as the research object, using the method of numerical analysis establishes the finite element model and its dynamic analysis model for the main components of test frame. Through the model simplified, the statics analysis, stability analysis and modal analysis is given respectively. The main content includes:Firstly, establishing the finite element model of three kinds of structure forms plate spring, transition and flexible parts and writing the MATLAB-m finite element calculation program, which gives the unified way for calculating the elastic resistance of the single plate spring to multiple paragraphs and designing the algorithm to calculate the relationship between the axial force and displacement for transition. The results are all analytical expressions which contains the geometric parameter variables. With the analytical expression, the analysis of the trend of objective function with a parameter change, the optimal working point selection and structure optimization, etc. Compared to the application software, which can only output specific numerical results for the built structure model of inputting specific parameter values, it has higher accuracy. The results of analytical expressions can be more accurate for structure optimization design. Flexible parts are unfavorable use programming calculation because of its complex structure. Thispaper uses the SolidWorks Simulation on the finite element analysis, getting the axial displacement distribution cloud. The designed algorithm, train of thought and the results will prepare for structure optimization, the buckling analysis, the modal analysis, etc.Structure stability problem is another key factor influencing the performances of structure. The structural characteristics and stress distribution of plate spring in test frame determine it is the most easily buckling parts. This article establish the plate spring buckling analysis model according to the practical constraints and stress distribution and write the general procedures(MATLAB-m file) to calculate the buckling force, which calculate the buckling force for single, double and three sections of plate spring respectively. To the double plate spring widely used in the test frame, by changing the geometric parameters of the plate spring(length of functional section, rigid length, etc.) on the numerical analysis, the study analysis the stability influenced by changing the plate spring size using fitting polynomial method(Matlab – polyfit function). Research results show that the buckling force have different sensitivity and trends with different geometric parameters, calculation results provide a theoretical reference for subsequent spring design.Dynamic performance of test frame is the main source of dynamic measurement error. This paper get the simplified dynamic model with flexible parts, transition, plate spring and SRM-frame combination(four parts) and calculate the natural frequency of the simplified test frame, validating test frame’s natural frequency oscillation frequency away from the thrust frequency. Finally analyzing the method to improve natural frequency of the test frame, getting certain regularity, the analysis results provide a theoretical reference for subsequent test frame design.This article applies the MATLAB powerful numerical analysis and the finite element method in the SRM ground test technology research, which provides a new approach for the future research in design and optimization of the test frame. The designed algorithm has great generality, which can calculate accurately and rapidly only need to change theinitial parameters. The train of thought and the results in this article can forecast and judgment before design, which can provide a certain theoretical basis for designing a high quality test frame.