Analysis of Highly Coupled Thermal-Structural Responses in Morphing Radiative Bodies

Bertagne, Christopher L.; Hartl, Darren J.; Cognata, Thomas

doi:10.2514/6.2015-1510

Cited by 9 publications

(4 citation statements)

References 14 publications

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“…More advanced methods are capable of achieving second-order time accuracy at the expense of additional complexity [41], however, this work has only considered the sequential staggered procedure described above. This method has been verified for the engineering problem considered in prior work [44].…”

Section: Analysis Approachmentioning

confidence: 94%

“…Although there is no fundamental requirement that the meshes be identical between the partitions, doing so simplifies the implementation, as there is no need to interpolate or extrapolate between dissimilar meshes during the two-way exchange of field data. After a rigorous convergence study similar to that described in prior work, a step time of 5 min (2% of the total simulation time) is used [44]. Appendix provides additional details regarding the implementation of the partitioned analysis procedure.…”

Section: Finite Thermomechanically Coupled Finite Element Modelmentioning

confidence: 99%

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Coupled behavior of shape memory alloy-based morphing spacecraft radiators: experimental assessment and analysis

Bertagne

Walgren

Erickson

et al. 2018

Smart Mater. Struct.

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Thermal control is an important aspect of spacecraft design, particularly in the case of crewed vehicles, which must maintain a precise internal temperature at all times in spite of significant variations in the external thermal environment and internal heat loads. Future missions beyond low Earth orbit will require radiator systems with high turndown ratios, defined as the ratio between the maximum and minimum heat rejection rates achievable by the radiator system. Current radiators are only able to achieve turndown ratios of 3:1, far less than the 12:1 turndown ratio requirement expected for future missions. An innovative morphing radiator concept uses the temperature-induced phase transformation of shape memory alloy (SMA) materials to achieve turndown ratios that are predicted to exceed 12:1 via substantial geometric reconfiguration. Developing mathematical and computational models of these morphing radiators is challenging due to the strong two-way thermomechanical coupling not present in traditional fixed-geometry radiators and not widely considered in the literature. Although existing simulation tools are capable of analyzing the behavior of some thermomechanically coupled structures, general problems involving radiation and deformation cannot be modeled using publicly available codes due to the complexity of modeling spatially evolving boundary fields. This paper provides important insight into the operational response of SMA-based morphing radiators by employing computational tools developed to overcome previous shortcomings. Several example problems are used to demonstrate the novel radiator concept. Additionally, a prototype morphing radiator was designed, fabricated, and tested in a thermal environment compatible with mission operations. An associated finite element model of the prototype was developed and executed. Model predictions of radiator performance generally agree with the experimental data, giving confidence that the tools developed are able to accurately represent the thermomechanical coupling present in morphing radiators and that such tools will be useful in future designs.

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Section: Analysis Approachmentioning

confidence: 94%

Section: Finite Thermomechanically Coupled Finite Element Modelmentioning

confidence: 99%

Coupled behavior of shape memory alloy-based morphing spacecraft radiators: experimental assessment and analysis

Bertagne

Walgren

Erickson

et al. 2018

Smart Mater. Struct.

View full text Add to dashboard Cite

show abstract

“…This behavior is known as the two-way SME. To provide an alternative to traditional wire-based SMA actuation solutions, recent developments have shown SMA torsional actuators, commonly torque tubes, that can be trained and implemented in large-scale aerospace actuation applications such as wing twisting (Hartl and Lagoudas, 2007; Herrington et al, 2015; Sanders et al, 2004; Saunders et al, 2014), rotor blade twisting (Kennedy et al, 2004; Prahlad and Chopra, 2001), and space-based radiator morphing (Bertagne et al, 2015a). Reliable methods to accurately characterize and model the behavior of these torsional actuators under a variety of thermal and mechanical loading conditions have been studied by many authors (Keefe and Carman, 2000; Mabe et al, 2004, 2013; Mirzaeifar et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

A simplified model for high-rate actuation of shape memory alloy torque tubes using induction heating

Saunders

Boyd

Hartl

et al. 2017

Journal of Intelligent Material Systems and Structures

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Shape memory alloy actuators deliver high forces while being compact and reliable, making them ideal for consideration in aerospace applications. Induction heating of shape memory alloy actuators, specifically tubes that twist about the longitudinal axis, has recently been studied experimentally and computationally using finite element analysis. Reduced-order models for the torsional behavior of shape memory alloy tubes and induction heating of general metallic tubes exist, and thus, it is possible for these thermal and mechanical models to be combined and numerically solved. This work develops and implements an engineering model for inductively heated shape memory alloy tubes based on the reduction of the governing partial differential equations in space and time to an ordinary differential equation in time. An example solution is compared to finite element analysis results and agrees well. Finally, the ordinary differential equation is linearized and solved analytically. The linearized model agrees well with the nonlinear ordinary differential equation and finite element model.

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“…SMA torsional actuators, commonly torque tubes, can be used for large-scale applications. SMA torque tubes are particularly useful for actuation in aerospace applications such as wing twisting [5][6][7], rotor blade twisting [8,9], and space based radiator morphing [10,11]. Since the primary mode of operation in SMA tubes is not tensile, the methods traditionally used to train and characterize SMA wires are not applicable.…”

Section: Introductionmentioning

confidence: 99%

A validated model for induction heating of shape memory alloy actuators

Saunders

Boyd

Hartl

et al. 2016

Smart Mater. Struct.

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Shape memory alloy (SMA) actuators deliver high forces while being compact and reliable, making them ideal for consideration in aerospace applications. One disadvantage of these thermally driven actuators is their slow cyclic time response compared to conventional actuators. Induction heating has recently been proposed to quickly heat SMA components. However efforts to date have been purely empirical. The present work approachs this problem in a computational manner by developing a finite element model of induction heating in which the time-harmonic electromagnetic equations are solved for the Joule heat power field, the energy equation is solved for the temperature field, and the linear momentum equations are solved to find the stress, displacement, and internal state variable fields. The combined model was implemented in Abaqus using a Python script approach and applied to SMA torque tube and beam actuators. The model has also been used to examine magnetic flux concentrators to improve the induction systems performance. Induction heating experiments were performed using the SMA torque tube, and the model agreed well with the experiments.

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Analysis of Highly Coupled Thermal-Structural Responses in Morphing Radiative Bodies

Cited by 9 publications

References 14 publications

Coupled behavior of shape memory alloy-based morphing spacecraft radiators: experimental assessment and analysis

Coupled behavior of shape memory alloy-based morphing spacecraft radiators: experimental assessment and analysis

A simplified model for high-rate actuation of shape memory alloy torque tubes using induction heating

A validated model for induction heating of shape memory alloy actuators

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