Wave propagation in graphite/epoxy laminate due to impact
Abstract
Harmonic wave in a graphite/epoxy laminate was studied using a plate theory that includes transverse shear deformation. Propagation of stress wave front in the laminate was also investigated. The velocity with which the wave front propagates was discussed and the position of wave front as function of time was constructed using ray theory. Contact behavior between spherical steel indenters and graphite/epoxy laminates was determined by performing statical identification tests. Indentation was measured using a linear differential variable transformer which allowed more accurate estimations of permanent deformations in the laminate. Relation between permanent indentation and maximum indentation at unloading was found to be approximately linear from the test data. It was shown that the loading and reloading curves follow the power laws with n = 1.5 very well while the power index for the unloading curves exhibited wider scatter. The experimental contact laws were incorporated into a 9-node isoparametric plate finite element program for impact analysis. An impact experiment on graphite/epoxy laminated plate was conducted to verify the validity of the statically determined contact laws in the application of impact analysis.
- Publication:
-
Ph.D. Thesis
- Pub Date:
- 1982
- Bibcode:
- 1982PhDT........18T
- Keywords:
-
- Graphite-Epoxy Composites;
- Impact Loads;
- Laminates;
- Stress Waves;
- Wave Propagation;
- Deformation;
- Indentation;
- Isoparametric Finite Elements;
- Plates (Structural Members);
- Wave Fronts;
- Fluid Mechanics and Heat Transfer