Wave Propagation in Periodic Truss Structures.
Abstract
Wave propagation in periodic truss-work beams was analytically investigated. Transfer matrix methods were applied to the analysis of two truss beams. The results of a truss with members modelled as pinned rods agree well with results obtained from equivalent continuum models of the same structure. Use of beam models for the truss members shows that the pinned rod truss model loses fidelity at the first resonant frequency of the lateral motion of the truss members. The pinned beam truss exhibits complicated mechanical filtering properties. Each travelling wave mode experiences alternating stop, pass, and complex mode bands as a function of frequency. It was shown that complex modes cannot exist alone and must form in groups of four. Net power flow in right/left-going complex mode pairs is found to be zero. Scattering matrices were determined for fixed and free boundary conditions. The phase closure principle was then used to determine natural frequencies of the truss. It was found that closely spaced resonant frequencies were not identified by this method. Computed results show subtle erroneous characteristics which are attributed to numerical effects. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 1987
- Accession Number
- ADA176548
Entities
People
- Joel Signorelli
Organizations
- Air Force Institute of Technology