Composite self-healing system

Abstract

An advanced reflexive structure system is disclosed. The reflexive system mimics the pain withdrawal reflex on which the human body relies. The reflexive system incorporates a continuous health and performance monitoring system via an embedded dielectric film, an adaptive composite structure based on shape memory composite material, and an intelligence system which will be interfaced with both the health / performance sensors and the adaptive structure. When activated shape memory polymer will recover its structural integrity via shape recovery and a reptation healing process. These features enable the use of SMP as an adaptive structure in the proposed reflexive system. The development of a reflexive system for structures will enable increased safety and security and demonstrate a better understanding of integrated performance systems. This reflexive technology could find immediate implementation on all current and future systems and future implementation on platforms such as the International Space Station, Lunar, and Martian habitats.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application claims priority from U.S. Provisional Application Ser. No. 60 / 911,673 filed Apr. 13, 2007, U.S. Provisional Application Ser. No. 60 / 911,682 filed Apr. 13, 2007, and U.S. Provisional Application Ser. No. 60 / 911,665 filed Apr. 13, 2007.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH[0002]This invention was made with U.S. Government support under Contract No. NNL05AA97C awarded by National Aeronautics and Space Administration and Contract No. NNL06AA07C awarded by the National Aeronautics and Space Administration to Cornerstone Research Group Inc. The U.S. Government has certain rights in the invention.BACKGROUND OF THE INVENTION[0003]1. Field of the Invention[0004]This application relates to the self-repair of polymer and polymer composite structures. The disclosed method of achieving this is to design and incorporate smart, intelligent, and adaptive systems into the structures composed of adaptive materials such as dynami...

AI Technical Summary

Benefits of technology

[0027]An advanced sense and respond technology comprised of multiple technologies to enhance survivability of future systems constructed of lightweight resins or composites is disclosed. The system is designed to react to detected damage with health monitoring by locally activating shape recovery and healing mechanisms of the adaptive polymer matrix or adaptive polymer matrix composite structure through the use of proven health monitoring technology to sense the location and significance of the damage and new healable dynamic elastic polymers and dynamic elastic polymers composites, an intelligent control system that integrates the system of technologies seamlessly and characterize the overall effectiveness.

[0030]Replacing traditional metallic structures with composites offers the end user increased functionality including higher specific mechanical properties, customizable ply schedules for tailored properties, and low coefficient of thermal expansion. Introduction of composite materials into structural applications does however result in specific design considerations including failure mechanisms. The failure mechanism for composites, as compared to traditional structural materials including concrete and steel, are more difficult to predict and monitor for. This change in failure mechanism results in the necessity for expensive, and time consuming, non destructive evaluation (NDE) to monitor structural health. This requirement for NDE drives up the cost of composite integration therefore increasing the barrier to entry.

[0032]One method of achieving this is to design and incorporate smart, intelligent, and adaptive systems. Such systems will allow for continuous health and performance monitoring, fast and decisive information processing to ensure that the system is “highly aware” of its current health status and unparalleled in its adaptability to detect and repair damage. Currently, most state-of-the-art health monitoring technologies can only deliver the indication of damage to the human operator via visual display. An integrated system consisting of smart, adaptive, and intelligent components will enable an advanced mission system to sense and immediately recover from physical damage on-the-fly while informing the operator of the situation but not requiring a response. Currently there is no method of recovering from physical damage due to an unforeseen event.

[0035]A better approach to composite repair is modular structural design that if a failure occurs in the structure, a modular section can be removed and replaced with a new section that can be fabricated at a separate location. This approach eliminates the necessity for costly in place curing equipment as well as the potential elimination of having an engineer evaluate the structure since it will be replaced with the exact material that was damaged. This process still does require the structure to be monitored by a human operator to determine if a failure has occurred as well as taking the necessary actions required to complete the structural repair. This approach also requires additional design time to ensure that each aspect of the design is modular and has the ability to be replaced section by section if required.

[0036]The reflexive system disclosed enables real time health monitoring of in use composite structures as well as the ability to repair damage thus restoring cold mechanical properties to the structure. The integration of this system eliminates the need for a dedicated user, or team of users, to monitor the results of the integrated health monitoring system as well as offers an in place repair capability. Having the repair mechanism in place greatly reduces the amount of time for repair through the elimination of needing to schedule a repair crew. Time is also saved through the way that a repair is conducted. Rather than having to either cure a composite in place or remove a section and mechanically fasten a new section into place, repairs can be completed simply through the application of heat to the structure. It is for these reasons that both time and money are saved through this technology as well as a minimization of structural down time.

Problems solved by technology

Introduction of composite materials into structural applications does however result in specific design considerations including failure mechanisms.

The failure mechanism for composites, as compared to traditional structural materials including concrete and steel, are more difficult to predict and monitor for.

This change in failure mechanism results in the necessity for expensive, and time consuming, non destructive evaluation (NDE) to monitor structural health.

This requirement for NDE drives up the cost of composite integration therefore increasing the barrier to entry.

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