LOW VELOCITY IMPACT BEHAVIOR OF VARTM MANUFACTUREDAFFORDABLE WOVEN ROVING COMPOSITES

摘要

Woven Roving composites have good properties in mutually orthogonal directions; morernbalanced properties than unidirectional laminates and have better impact resistance. These wovenrnroving composites are being considered for naval structural applications in place of conventionalrnmetals. They are being manufactured by using a new process known as Vacuum Assisted ResinrnTransfer Molding (VARTM). This new process is low cost, affordable and suitable for high volumernmanufacturing environment. One of the popular sandwich woven roving composites is fabricatedrnusing woven roving glass fibers and 510 A-40 Derakane vinyl ester resin system in conjunction withrnbalsa and PVC core material by using the VARTM process. Before this new generation of compositernmaterials can be used for naval structural applications, it is essential to study the survivability ofrnaffordable composites under low velocity impact loadings. This study will address the effects of lowrnvelocity impact on VARTM manufactured woven roving fiberglass composite panels. In thernexperimental program 6 ply VARTM manufactured woven roving composite panels were subjected tornlow velocity impact loads. The laminates were held in a special fixture, which was designed tornsimulate clamped boundaries. Impact experiments were conducted using a Dynatup low velocityrnimpact-testing machine where a drop-weight system was used to strike each panel at 90rn900 incidencesrnunder controlled conditions of impact velocity. The impactor used was of a constant weight and tiprndiameter. The impact height and hence the velocity and energy were used as variables in the study.rnPreliminary impact tests were performed to establish the incipient damage (lower bound) andrnpenetration energy (upper bound) for woven roving fiberglass laminates. Several energy levels werernselected to study the progressive deformation and damage mechanics