The Shock Response Prediction of Spacecraft Structure Based on Hybrid FE-SEA Method

Abstract

An improved method based on the Hybrid Finite Element-Statistical Energy Analysis (FE-SEA) method and quasi-steady state theory is proposed to predict the response of spacecraft structure during the process of pyrotechnics separation. Firstly, the amplitude–frequency value of shock load is obtained by using time-frequency conversion technology. Then, according to the frequency response characteristics of each part of the spacecraft structure, a more accurate hybrid FE-SEA model is established. The piecewise loading method is used to predict the response of the hybrid model. Finally, the time domain response results are reconstructed, and the shock response spectrum (SRS) is calculated. Based on the test system of simulating pyroshock, the shock experiment of spacecraft structure is conducted. The high frequency and high velocity character of pyroshock could be effectively simulated, and an accurate shock force function could be obtained through the experiment. This indicates that the numerical results are in line with the ones of the experiment. The SRS obtained from experiments and calculations have similar trends and amplitudes. This conclusion verifies the rationality and sufficient accuracy of the novel method in this paper. The novel method presented in this paper greatly improves the computational efficiency. At the same time, it provides theoretical guidance for shock response prediction of spacecraft structure by steady-state methods.

Impact response analysis of vibration system with inerter

“…Where [M], [C], and [K] are the mass, damping and stiffness matrix, respectively. By inserting the mass, damping and stiffness matrix in equation (10) into equation (11), we get…”

“…The eigenvalues analysis is performed using the inertia and elastic force components in equation (10). In this condition, equation (10) can be written as :…”

“…Research on impact-induced vibration on aircraft during landing has been conducted by Son et al 8 and Sivaprakasam and Muneer. 9 Shock response prediction of spacecraft structure based on hybrid FE-SEA method during pyrotechnics separation process was studied by Wang et al 10 Fahem and Alshamma 11 analyzed the effect of impact loading on dynamic crack propagation in thin and isotropic thick plates. A study of dynamic impact load effects due to railroad wheel profile roughness was conducted by Ahlbeck.…”

Comparison of predictive techniques for spacecraft shock environment

“…The most common technique is the Statistical Energy Analysis (SEA): the main idea in SEA is that a complex structure (e.g., a spacecraft) is described as a network of subsystems where the stored and exchanged energies are analysed [3].When dealing with mid frequency there is no universally accepted method as the structure does show neither a deterministic nor a chaotic behaviour. Accordingly, [4] proposed an improved methodology based on the Hybrid Finite Element-Statistical Energy Analysis (FE-SEA) method. Since SEA is able to deal with high frequency problems, combining FEM and SEA it is possible to cover the entire frequency range with rationality and sufficient accuracy of the prediction results.…”