Abstract
In order to ensure the safety of the missile-canister system in silo during the earthquake, a modified transfer matrix method is provided to study the dynamic characteristics of the system. Firstly, a discrete viscoelastic connected double-beam model is developed taking account of the structural nonuniformity and the discrete distribution of the adapters. Secondly, the transfer matrix method of a single beam is modified to solve the problem of discrete connection between the two beams of the double-beam model. Then the natural circular frequencies and mode shapes are calculated by the proposed method, comparing with the finite element method (FEM). Finally, the influence of the stiffness of radial vibration isolators and adapters on the dynamic characteristics of the system is analysed. The comparison shows that the results of the proposed method are well consistent with the FEM calculations and the proposed method is validated. The variations of the first six natural circular frequencies with radial vibration isolator stiffness and adapter stiffness are obtained, which provides a basis for the seismic-relieving design.
Highlights
Once the missile-canister system erected in silo encounters an earthquake, it’s easy to occur such accidents as shaking, collision with the silo body, local structural instability and internal equipment becoming ineffective caused by resonance
A launch vehicle or missile is always equivalent to a beam when analysing the vibration characteristics by the finite element method (FEM) and the transfer matrix method, which the shaking of liquid propulsion and the swinging of branch structure are well considered [1,2]
It can be seen from Tab.2 that the relative errors of the first six natural circular frequencies between the transfer matrix method presented in this paper and the FEM are within 2.0%
Summary
Once the missile-canister system erected in silo encounters an earthquake, it’s easy to occur such accidents as shaking, collision with the silo body, local structural instability and internal equipment becoming ineffective caused by resonance. As considering the structural flexibility, Zhang et al [6] regarded the missile as an equivalent beam and the adapter and canister as elastic solids, a dynamic simulation of the launching process of the cold-launched missile in silo was carried out. A double-beam model has been established which taking account of the nonuniformity and discreteness in actual structure and simplified reasonably, in order to accurately analyse the dynamic characteristics of the missile-canister system in silo and appropriately optimize the seismic-relieving design. It is composed of multiple lumped masses, massless beams and several spring damping components. Damper c1, the k2 and c2 are substituted for the adapter
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