The effect of scaling on the performance of elastomer composite actuators

Peel, Larry D.; Baur, Jeff; Phillips, David M.; McClung, Amber J. W.

doi:10.1117/12.848678

Cited by 4 publications

(18 citation statements)

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“…Recent scientific approaches have demonstrated interesting concepts by implementing fiber-reinforced elastomers with distinct hyper-elasticity as so-called smart materials. The concept of these soft matter applications can be found in the field of aerospace or automotive industries as aeroelastic wings [11,12] with the ability to serve multiple functions for optimized aerodynamic performances. Another aspect for the usage of morphing structures are in soft robotic applications such as exoskeletons [13] or artificial fingers [14], where sufficient strength combined with significant large deformations have to be ensured.…”

Section: Introductionmentioning

confidence: 99%

The Tension-Twist Coupling Mechanism in Flexible Composites: A Systematic Study Based on Tailored Laminate Structures Using a Novel Test Device

et al. 2020

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The focus of this research is to quantify the effect of load-coupling mechanisms in anisotropic composites with distinct flexibility. In this context, the study aims to realize a novel testing device to investigate tension-twist coupling effects. This test setup includes a modified gripping system to handle composites with stiff fibers but hyperelastic elastomeric matrices. The verification was done with a special test plan considering a glass textile as reinforcing with different lay-ups to analyze the number of layers and the influence of various fiber orientations onto the load-coupled properties. The results demonstrated that the tension-twist coupling effect strongly depends on both the fiber orientation and the considered reinforcing structure. This enables twisting angles up to 25° with corresponding torque of about 82.3 Nmm, which is even achievable for small lay-ups with 30°/60° oriented composites with distinct asymmetric deformation. For lay-ups with ±45° oriented composites revealing a symmetric deformation lead, as expected, no tension-twist coupling effect was seen. Overall, these findings reveal that the described novel test device provides the basis for an adequate and reliable determination of the load-coupled material properties between stiff fibers and hyperelastic matrices.

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Section: Introductionmentioning

confidence: 99%

The Tension-Twist Coupling Mechanism in Flexible Composites: A Systematic Study Based on Tailored Laminate Structures Using a Novel Test Device

et al. 2020

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“…The primary advantage of these flexible composites is the ability to tailor physical properties such as deformation, stiffness, and non-linearity over a much wider range than conventional fiber-reinforced rubbers [ 10 , 14 ]. These concepts can be found in some recent developments, such as artificial muscles [ 15 ], exoskeletons, or artificial fingers [ 16 ], as well as aeroelastic wings [ 17 , 18 ] with significantly large deformations. Generally, it is evident that these applications of fiber-reinforced elastomers are mostly subjected to cyclic loading.…”

Section: Introductionmentioning

confidence: 99%

Viscoelastic Behavior of Glass-Fiber-Reinforced Silicone Composites Exposed to Cyclic Loading

et al. 2020

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The aim of this work was to analyze the influence of fibers on the mechanical behavior of fiber-reinforced elastomers under cyclic loading. Thus, the focus was on the characterization of structure–property interactions, in particular the dynamic mechanical and viscoelastic behavior. Endless twill-woven glass fibers were chosen as the reinforcement, along with silicone as the matrix material. For the characterization of the flexible composites, a novel testing device was developed. Apart from the conventional dynamic mechanical analysis, in which the effect of the fiber orientation was also considered, modified step cycle tests were conducted under tensile loading. The material viscoelastic behavior was studied, evaluating both the stress relaxation response and the capability of the material to dissipate energy under straining. The effects of the displacement rate of the strain level, the amplitude of the strain applied in the loading–unloading step cycle test, and the number of the applied cycles were evaluated. The results revealed that an optimized fiber orientation leads to 30-fold enhanced stiffness, along with 10 times higher bearable stress. The findings demonstrated that tailored reinforced elastomers with endless fibers have a strong influence on the mechanical performance, affecting the structural properties significantly.

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“…However, morphing aircraft systems may need to combine all three (actuator, Figure 1. Unpressurized, pressurized RMA sketches with dimensioned cross-section, and fabricated example [5].…”

Section: Introductionmentioning

confidence: 99%

“…An elastomeric bladder is used to prevent leakage. Figure 1 shows sketches with dimensions, braid angle and a pressurized RMA [5].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Characterization and application of shape-changing panels with embedded rubber muscle actuators

Peel¹,

Molina²,

Baur³

et al. 2013

Smart Mater. Struct.

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Cylindrical soft actuators efficiently convert fluid pressure into mechanical energy and thus offer excellent force-to-weight ratios while behaving similar to biological muscle. McKibben-like rubber muscle actuators (RMAs) were embedded into neat elastomer and act as shape-changing panels. The effect of actuator spacing and modeling methods on the performance of these panels was investigated. Simulations from nonlinear finite element models were compared with results from test panels containing four RMAs that were spaced 0, 1/2, 1, and 1.3 RMA diameters apart. Nonlinear ‘laminated plate’ and ‘rod & plate’ finite element (FE) models of individual (non-embedded) RMAs and panels with embedded RMAs were developed. Due to model complexity and resource limitations, several simplified 2D and 3D FE model types, including a 3D ‘Unit Cell’ were created. After subtracting the ‘activation pressure’ needed to initiate contraction, all the models for the individual actuators produced forces consistent with experimental values, but only the more resource-intensive rod & plate models replicated fiber/braid re-orientation and produced more realistic values for actuator contraction. For panel models, the Full 3D rod & plate model appeared to be the most accurate for panel contraction and force, but was not completed for all configurations due to resource limitations. Most embedded panel FE models produced maximum panel actuator force and maximum contraction when the embedded actuators are spaced between 1/2 and 1 diameter apart. Seven panels with embedded RMAs were experimentally fabricated and tested. Panel tests confirmed that maximum or optimal performance occurs when the RMAs are spaced between 1/2 and 1 diameter apart. The tested actuator force was fairly constant in this range, suggesting that minor design or manufacturing differences may not significantly affect panel performance. However, the amount of axial force and contraction decreases significantly at greater than optimal spacing. This multi-faceted work provides useful design, simulation fabrication, and test characteristics for shape-adaptive panels. Bending panels were demonstrated but not modeled. Developers of future shape-adaptive air vehicles have been provided with additional simulation and design tools.

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The effect of scaling on the performance of elastomer composite actuators

Cited by 4 publications

References 0 publications

The Tension-Twist Coupling Mechanism in Flexible Composites: A Systematic Study Based on Tailored Laminate Structures Using a Novel Test Device

The Tension-Twist Coupling Mechanism in Flexible Composites: A Systematic Study Based on Tailored Laminate Structures Using a Novel Test Device

Viscoelastic Behavior of Glass-Fiber-Reinforced Silicone Composites Exposed to Cyclic Loading

Characterization and application of shape-changing panels with embedded rubber muscle actuators

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