A study of impact damage in composite laminates
Damage produced by low velocity impact in a graphite fiber composite plate is analyzed. The distribution of damage produced by impact in each plate layer was calculated by employing Di Sciuva's composite laminate theory with Hashin's failure criterion for fiber reinforced composites. The principle of virtual work was applied in the formulation of the problem. The material was regarded as damaged when its designed strength was reduced by the failure of its constituents. The constituent failures consisted of matrix crackings, fiber breakages, and delamination between layers. According to the damage modes, the moduli of materials in the damaged zone were reduced according to the failure criteria. Structure integrity was assumed to be unaffected by the local damage, although the structure stiffness was reduced. Only damage produced by low velocity impact was analyzed. Low velocity impact was defined as when the contact time duration between the impactor and the target plate was long in comparison with the natural period of the target plate so that the effect of wave motions in the plate could be neglected. Dynamic deformation of the target plate was represented by the lower vibrational modes of the plate. Plate deformation and the corresponding three dimensional stress field in all layers were calculated by employing Di Sciuva's composite laminate plate theory. Interaction between layers and its role in damage propagation was studied. With a low velocity projectile, most of the damage in the plate was caused by matrix crackings and delamination. Damage caused by fiber breakage was confined to the area under and near the contact area between the impactor and the target plate. Fiber orientation played a major role in damage containment. Fibers in the consecutive layers must be at an angle with respect to each other to achieve an effective containment of the impact induced damage.
- Research Organization:
- Texas Univ., Austin, TX (USA)
- OSTI ID:
- 6946786
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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