Research Of The Six-component Mechanical Measurement System Of Full-size Ramjet

With the progress of the ramjet technology,the technical index of simulation test equipment on the ground is more and more advanced.In order to be able to carry out the full-size ramjet test on the ground,the six-component mechanical measurement system with large size and large load is developed.The development process is divided into four stages,the first stage is designing of overall technical scheme,the second stage is research of key technology and structural designing,the next is finite element analysis of system structure,the last one is system calibration and verification test.According to the theory of aerodynamic load of ramjet,through the force system transform to calculate the designing of mechanical load measurement system,with reference to the structure of the wind tunnel cassette balance layout,design the system for the orthogonal layout structure fabricated six weight balance.According to the principle of material mechanics knowledge and differential single axis is built the mathematical model of double circular flexure hinge and further deduced the tandem two-axis double circular corner stiffness of flexure hinge and tensile stiffness calculation formula of design provides a theoretical basis for flexible rod.Based on the designed flexible bar,other parts and integral structures of the mechanical measurement system are further designed.In order to check and verify that the system structure of the strength and stiffness,the flexible rod and system structure of the finite element analysis,through to the various key direction on the surface of the key features of quantitative and qualitative analysis,detailed elaborated the advantages and disadvantages of the system structure,and probes into the mutual interference between the components in the qualitative analysis.Calibration system is in order to get the system calibration formula,the precision of the inspection system,using the unit calibration data analyzed the linearity of various air volume and other component to this air volume,and then using the six groups of unit calibration data through linear regression and least squares fitting the calibration formula for the system,and get the measuring precision of each component.The system verification test was carried out after all the subsystems were installed in the test platform.The first is to measure the aerodynamic loads of the engine,and the other is to measure the aerodynamic load of the engine during the ignition process.Both experiments were carried out smoothly and successfully,the measurement data met the requirements of precision,and the measurement curve was consistent with the change rule of engine aerodynamics.