System-Level Design of a Shape Memory Alloy Actuator for Active Clearance Control in the High-Pressure Turbine

DeCastro, Jonathan A.; Melcher, Kevin J.; Noebe, Ronald D.

doi:10.2514/6.2005-3988

Cited by 14 publications

(12 citation statements)

References 15 publications

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“…The Brinson model experiences discontinuities when the material is stressed between two critical limits and the temperature is reduced to soothe alloy transitions from a temperature-induced martensite state to a stress-induced martensite state, so we adopt the modified Brinson model (1993) as enunciated by DeCastro et al (2005DeCastro et al ( , 2006. In this modified state, the stress-temperature diagram is as shown in Figure 8.6.…”

Section: Non-linear Constitutive Relationshipsmentioning

confidence: 99%

Dynamics of Thermoelastic Media: Shape Memory Alloys

Vepa¹

2010

Dynamics of Smart Structures

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Layered elastic structures are usually subject to a variety of dynamic loads, including changes in temperature. Because the layers may possess varying thermo-mechanical properties, temperature changes would induce non-uniform stresses within the structure. Thus, the study of the thermoelasticity of such structures is of paramount importance. It is not enough to understand the influence of temperature changes on the state of stress in the structure, it is also essential to understand how the changes in the state of stress influence the temperature distributions within the structure. To be able to systematically model the constitutive relationships, it is essential to revisit the basic thermodynamic concepts (Vedantam, 2000) to establish the foundations of linear thermoelasticity. Basic Thermodynamic ConceptsThe first law of thermodynamics is essentially the statement of the principle of conservation of energy applied to thermodynamic systems. Thus, the variation in the internal energy of a thermodynamic system due to transformation of the state of the system U can be expressed in terms of the work W performed during the transformation and the amount of energy Q received by the system in forms other than work, as U = Q − W .The first law arose primarily to state the impossibility of constructing a machine that could create energy. It places no limitations on the possibility of transforming heat into work or work into heat, as they are different forms of energy. However, the second law explicitly places certain limitations on how much heat can be transformed to useful work. Thus, the second law of thermodynamics states that 'A transformation whose only final result is to transform into work, heat extracted from a source which is the same temperature throughout is impossible'. Alternatively, the second law may be stated as 'A transformation whose only final result is to transfer heat from a body at a given temperature to a body at a higher temperature is impossible'. This implies that only part of the heat that is absorbed by the system from the source at a higher temperature can be transformed to useful work and that the rest of the heat must be surrendered to the source at lower temperature. This leads naturally to the concept of entropy, and the second law could be stated as 'For any transformation occurring in an isolated system the entropy of the final state can never be less than that of the initial state'. Thus, if an isolated system is Dynamics of Smart StructuresRanjan Vepa

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Section: Non-linear Constitutive Relationshipsmentioning

confidence: 99%

Dynamics of Thermoelastic Media: Shape Memory Alloys

Vepa¹

2010

Dynamics of Smart Structures

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“…Additionally, if an engine component can "adapt" to changes in the environment, additional gains can be achieved. An example of this would be active turbine tip clearance control, where tip shrouds could be adjusted to compensate for increased turbine airfoil tip wear or rub [7]. Another example is active flow control.…”

Section: Nasa and Aeronauticsmentioning

confidence: 99%

NASA and Superalloys: A Customer, a Participant, and a Referee

Nathal¹

2008

Superalloys 2008 (Eleventh International Symposium)

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NASA has had a long history of research and development in the field of superalloys. These efforts have continued today, where the latest advancements in turbine disk and blade technologies are being developed Although NASA does support military flight systems, it's predominant role is in supporting civilian air transportation systems, and thus has goals for improving fuel efficiency, emissions, noise, and safety of today's aircraft. NASA has traditionally served several distinct but complimentary roles as participants in multi-disciplinary research teams, as customers who fund research and development efforts at industry and universities, and as referees who can address broad issues that affect the entire aeronautics community. Because of our longer range viewpoint, we can take on higher risk, higher reward research topics. NASA can also serve as an intermediary between the basic research performed primarily at universities and the development efforts emphasized by industry. By interacting with individual companies, NASA can identify areas of general interest and problems common to a large portion of the aeronautics community, and devise programs aimed at solving these problems. In space missions, NASA is a direct customer responsible for developing vehicles. In the case of the Space Shuttle, NASA has worked with various contractors to design and build numerous components out of superalloys. Another fascinating area for the use of superalloys is in power systems for long life applications in space. Potential missions include providing electric power for deep space missions, surface rovers, including lunar and Mars, and stationary power generators on the lunar surface.

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“…19). A constitutive model based on uniaxial tensile loads representative of alloy wires is therefore an appropriate choice.…”

Section: Brinson Quasi-static Constitutive Modelmentioning

confidence: 99%

Development of a numerical model for high-temperature shape memory alloys

DeCastro

Melcher

Noebe

et al. 2007

Smart Mater. Struct.

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A new thermomechanical hysteresis model for a high-temperature shape memory alloy (HTSMA) actuator material is presented. The proposed Brinson-Preisach model is capable of predicting the strain output of a tensile-loaded HTSMA when excited by arbitrary temperature-stress inputs for the purpose of actuator and control design. Quasistatic generalized Preisach hysteresis models available in the literature require large sets of experimental data for model identification at a particular operating point, and substantially more data for multiple operating points. The minor loop algorithm is an alternate approach to common Preisach methods that is better suited for research-stage alloys, such as recently developed HTSMAs, for which a complete identification database is not yet available. A detailed description of the minor loop hysteresis algorithm is presented in this paper and a methodology for determination of model parameters is introduced. The algorithm is assembled together with a modified form of the one-dimensional Brinson constitutive equation to provide a continuous thermomechanical response even within the characteristically wide detwinning region of the HTSMA. The computationally efficient algorithm is shown to demonstrate each of the unique characteristics of Preisach minor loop hysteresis over the usable actuation range in high-stress, high-temperature applications.

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System-Level Design of a Shape Memory Alloy Actuator for Active Clearance Control in the High-Pressure Turbine

Cited by 14 publications

References 15 publications

Dynamics of Thermoelastic Media: Shape Memory Alloys

Dynamics of Thermoelastic Media: Shape Memory Alloys

NASA and Superalloys: A Customer, a Participant, and a Referee

Development of a numerical model for high-temperature shape memory alloys

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