The present paper deals with a self-deployable graphite/epoxy composite structure using a partially flexible composite
(PFC) with shape memory alloy wires. The present paper introduces the fabrication processes of the PFC. Two different
matrices are used for the PFC: epoxy resin for the normal main part, and silicone rubber for the folding line. Since the
fibers are continuous in the structure, the PFC has the same tensile strength as a normal composite. We investigate
graphite fiber breakages during the folding process by considering changes in electrical resistance. An SMA wire is
embedded in the PFC to keep the folded configuration without loading and self-deployment is achieved using Joule
heating. The results confirm that a flexible part of adequate length enables foldable composite structures without causing
carbon fiber breakages. The embedded SMA wire realizes compactly folded composite panel structures without loading
and Joule heating of the SMA wires enables self-deployable composite structures.
For Unmanned aerial vehicles, a morphing wing is desired to improve the maneuverability and reduce the total weight
of structures. Our research group has developed a foldable composite structure for a morphing wing skin plate by using
Carbon Fiber Reinforced Plastics (CFRP). The material system is called Partially Flexible Composites (PFC). In the
present paper, PFC is introduced and a self-sensing system of the PFC is investigated. Since carbon fibers have
electrical conductivity, damages of the PFC can be detected by monitoring electrical resistance changes of the PFC.
This method is called Electrical Resistance Changes Method. An electrical resistance model of the PFC is built and a
relationship of ratio of fiber fractures and electrical resistance changes is obtained. Then, to investigate the
performance of the PFC, cyclic-bending tests are conducted. Damages of the PFC caused by cyclic-bending are
detected by using ERCM. As a result, the PFC with more than 10mm-long flexible part has almost no damage; the
stiffness of the structure remains unchanged. After that, a McKibben pneumatic artificial muscles actuator is made
and it is founded that this can be applied to the PFC as an actuator. This actuator consists of a silicon rubber and a
carbon fiber that are the same as the material of flexible part of the PFC. This enables us to make actuator-integrated
composite structures. In the present study, the applicability of the McKibben pneumatic artificial muscles actuator is
investigated.
Designs for future spacecraft have been conceived with very large lightweight apparatus and structures. New techniques
of packaging to be stowed into existing launch vehicles are desired. A kind of current deployment techniques is
mechanical hinge mechanisms and this results in an increase of weight in structures. In the present study, Partially-
Flexible CFRP with SMA embedded (PFC-S) is proposed to be appropriate for the deployable structures. The PFCS
consists of two kinds of matrices: high-stiffness resin matrix and low-stiffness rubber matrix, and the SMA are
embedded in low-stiffness rubber part. It can be deformed and folded for packaging and it can be deployed with over 80°C due to the SMA embedded. Since the width of PFCS influences the foldable shape, the relationship between width of
the PFCS and the curvature of foldable shape is investigated by using specimens with various width of flexible part. Also
the effect of SMA embedded and temperature change on bending stiffness in specimen is measured. As a result, it is
found that narrow PFCS specimen keeps appropriate shape with comfortable curvature, and SMA embedded and
elevated temperature increases bending modulus of the PFCS specimen.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.