Analysis procedures for optimizing the core of composite sandwich panels for blast resistance.

摘要

As highlighted by recent domestic and international events, blast threats from terrorist activity have the potential to lead to extensive economic and physical damage as well as loss of life. This leads to a need for more efficient structures to withstand these threats. Composite materials have much promise for use in this area, particularly in applications where lightweight materials are necessary. The objective of this thesis is to evaluate two modeling techniques aimed at use for the design of the core of composite panels to resist blast events. The first is a simple analytical approach, while the second is a finite element approach. With the successful development of such a model, extensive experimental testing can be minimized.;The scope of this work begins with a comprehensive literature review of experimental testing on a variety of different composite panels. From this review, it is shown that sandwich panels have the best potential to resist blast forces, and also lend themselves to the most customizable designs.;With this panel type selected, the first type of analysis is performed. This analysis consists of idealizing a composite sandwich panel as a beam on an elastic foundation. The top facesheet is transformed into a simple beam, while the stiffeners in the composite structure are transformed into springs. Through this analysis, loads and deflections in the stiffeners can be determined. Through this approach the strengths of three designs are normalized and compared to determine which is most efficient.;The finite element approach is then used, which allows for refining the model by considering dynamic loading and multiple failure modes. This is carried out using the commercially available finite element software Abaqus Explicit. To evaluate the accuracy of these models, a series of dynamic loading tests were performed using a Dynatup 9200 drop tower. Visual images of the failure of the panels were captured with a high speed camera, which were compared to the finite element output. With this working model, detailed analysis of blast events can be considered without the high cost of experimental testing.