High Strain Composites

Murphey, Thomas W.; Francis, William; Davis, Bruce; Mejia-Ariza, Juan M.

doi:10.2514/6.2015-0942

Cited by 54 publications

(12 citation statements)

References 66 publications

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“…The HSC field has grown significantly since the early 2000s and is well defined in the seminal paper by Murphey et al 13 One recent flight success involving HSC materials was the Air Force Research Laboratory Roll-Out Solar Array that flew on the International Space Station in 2017. 14 The use of HSC materials for precision hinges was originally shown in the literature by Domber et al 12 As indicated in Table 1, their work found submicron-level axial and transverse deployment precision for one HSC hinge design and higher precision error for two other hinges made from different composite layups.…”

Section: High-strain Composite Hingesmentioning

confidence: 99%

Recent Developments in Precision High Strain Composite Hinges for Deployable Space Telescopes

Echter

Silver

D'Elia

et al. 2018

2018 AIAA Spacecraft Structures Conference

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Future large space-based telescopes will require precision mechanisms for deployment or alignment after they reach orbit. This research effort seeks to develop deployable primary-mirror telescope technologies that leverage recent advances in mirror phasing, actuation and deployable structure technologies. One way to obtain a precise deployed position of the optical components is with structures incorporating precision High-Strain Composite (HSC) hinges. This paper focuses on characterizing the deployment precision of individual HSC hinges and of a support frame utilizing multiple HSC hinges. Measurements of certain individual HSC hinges demonstrate position precision as low as 0.6 µm and angular precision as low as 6 µrad. A deployable frame concept produced axial precision of 0.2 µm, piston precision of 2.3 µm and angular precision of 6.3 µrad. A few modifications to the frame test setup are proposed that may improve the piston precision results.

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Section: High-strain Composite Hingesmentioning

confidence: 99%

Recent Developments in Precision High Strain Composite Hinges for Deployable Space Telescopes

Echter

Silver

D'Elia

et al. 2018

2018 AIAA Spacecraft Structures Conference

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“…Equation (8) states that the relaxation modulus at temperature T and time t is the same as that at the reference temperature T 0 and reduced time t 0 . Hence, it follows that a master curve can be constructed at any arbitrarily chosen reference temperature by shifting to the reference temperature the relaxation moduli at any other temperatures.…”

Section: Review Of Linear Viscoelasticitymentioning

confidence: 99%

“…T HE release of strain energy stored in thin-shell deployable structures provides a very effective and widely used deployment actuation mechanism, which traditionally has been implemented in the form of open-section, cylindrical thin shells with uniform radius of curvature (tape springs), made of metals such as spring steel or beryllium copper alloys [1][2][3][4]. Recently, the higher modulus-to-mass ratio of advanced composite materials and the wider range of shapes that can be made at low cost have motivated research in ultrathin composite deployable structures [5][6][7][8], and structures of this kind are increasingly being considered for flight missions. Notable examples of composite deployable structures include the 6.8-m-diam Springback reflector antennas on the Mobile Satellite System [9] and the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) antennas on the Mars Express Spacecraft [10,11].…”

mentioning

confidence: 99%

Micromechanics Models for Viscoelastic Plain-Weave Composite Tape Springs

Kwok

Pellegrino

2017

AIAA Journal

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The viscoelastic behavior of polymer composites decreases the deployment force and the postdeployment shape accuracy of composite deployable space structures. This paper presents a viscoelastic model for single-ply cylindrical shells (tape springs) that are deployed after being held folded for a given period of time. The model is derived from a representative unit cell of the composite material, based on the microstructure geometry. Key ingredients are the fiber volume density in the composite tows and the constitutive behavior of the fibers (assumed to be linear elastic and transversely isotropic) and of the matrix (assumed to be linear viscoelastic). Finite-element-based homogenizations at two scales are conducted to obtain the Prony series that characterize the orthotropic behavior of the composite tow, using the measured relaxation modulus of the matrix as an input. A further homogenization leads to the lamina relaxation ABD matrix. The accuracy of the proposed model is verified against the experimentally measured timedependent compliance of single lamina in either pure tension or pure bending. Finite element simulations of single-ply tape springs based on the proposed model are compared to experimental measurements that were also obtained during this study.

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“…Specifically, the focus is on reducing torsional stiffness within composite tape springs and evaluating x , in the longitudinal direction, and an 'opening-out' moment, M th y , in the hoop direction the feasibility of zero torsional stiffness prestressed composite shell structures. Such compliant mechanisms have potential for applications in medical exoskeletons [22], deployable spacecraft structures [23], and morphing aerostructures [18]. The paper is structured as follows.…”

Section: Introductionmentioning

confidence: 99%

Thermal Prestress in Composite Compliant Shell Mechanisms

Stacey

O’Donnell

Schenk

2019

Journal of Mechanisms and Robotics

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This paper explores the ability to tailor the mechanical properties of composite compliant shell mechanisms, by exploiting the thermal prestress introduced during the composite laminate cure. An extension of an analytical tape spring model with composite thermal analysis is presented, and the effect of the thermal prestress is studied by means of energy landscapes for the cylindrical composite shells. Tape springs that would otherwise be monostable structures become bistable and exhibit greater ranges of low-energy twisting with thermally induced prestress. Predicted shell geometries are compared with finite element (FE) results and manufactured samples, showing good agreement between all approaches. Wider challenges around the manufacture of prestressed composite compliant mechanisms are discussed.

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High Strain Composites

Cited by 54 publications

References 66 publications

Recent Developments in Precision High Strain Composite Hinges for Deployable Space Telescopes

Recent Developments in Precision High Strain Composite Hinges for Deployable Space Telescopes

Micromechanics Models for Viscoelastic Plain-Weave Composite Tape Springs

Thermal Prestress in Composite Compliant Shell Mechanisms

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