Electromagnetic Shielding by Advanced Composite Materials.
Abstract
The transmission of electromagnetic waves through planar sheets and cylindrical shells of advanced composite laminates is considered in both the frequency and time domains. Attention is concentrated on the frequency range characteristic of the nuclear electromagnetic pulse. The composite laminates are modeled for the purposes of this study by isotropic dielectric or conducting materials. A new 'boundary connection operator' is developed to describe the connection between the tangential electric and magnetic fields on either side of a general multilayer shield. An equivalent sheet impedance operator is developed to describe the bonded wire-mesh screen which is often incorporated in boron-epoxy composite laminates to improve their shielding effectiveness. These analyses are used to study the transmission of EMP signals through planar composite sheets and into cylindrical composite shells in the frequency and time domains. Both graphite-epoxy and 'screened' boron-epoxy laminates are considered. Numerical results are presented to illustrate the analytical formulas which are derived. It is found that the shielding effect of a screened boron-epoxy composite laminate is essentially that of the screen itself. The laminate only has an effect on the equivalent sheet impedance of the screen for parallel-polarized fields, and this effect is relatively minor over the EMP frequency spectrum.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1978
- Accession Number
- ADA058808
Entities
People
- K. F. Casey
Organizations
- Kansas State University