A Hybrid Actuation System (HYBAS) and Aerospace Applications

2005 ◽  
Vol 888 ◽  
Author(s):  
Ji Su ◽  
Tian-Bing Xu ◽  
Shujun Zhang ◽  
Thomas R. Shrout ◽  
Qiming Zhang
Keyword(s):  
Single Crystal ◽  
High Performance ◽  
Theoretical Modeling ◽  
Synthetic Jet ◽  
Aerospace Applications ◽  
Actuation System ◽  
Electromechanical Responses ◽  
Control Technologies ◽  
Langley Research Center ◽  
Hybrid Actuation

ABSTRACTAn electroactive polymer-ceramic hybrid actuation system (HYBAS) has been developed at NASA Langley Research Center. The system demonstrates significantly-enhanced electromechanical performance by cooperatively utilizing advantages of a combination of electromechanical responses of an electroative polymer (EAP), and an electroactive ceramic single crystal, PZN-PT single crystal. The electroactive elements are driven by a single power source. Recently, a modification of HYBAS has been made to increase the capability of air driving for synthetic jet devices (SJ) used in aerodynamic control technologies. The dependence of the air driving capability of the modified HYBAS on the configuration of the actuating device has been investigated. For this particular application, the modified HYBAS demonstrated a 50% increase in the volume change in the synthetic jet air chamber, as compared with that of the HYBAS without the modification. The theoretical modeling of the performances of the HYBAS is in good agreement with experimental observation. The consistence between the theoretical modeling and experimental test make the design concept an effective route for the development of high performance actuating devices for many applications. The theoretical modeling, fabrication of the HYBAS and the initial experimental results will be presented and discussed.

Theoretical Modeling for Electroactive Polymer-Ceramic Hybrid Actuation Systems

Aerospace ◽  
2004 ◽  
Author(s):  
Tian-Bing Xu ◽  
Ji Su
Keyword(s):  
Performance Optimization ◽  
High Performance ◽  
Electroactive Polymer ◽  
Actuation System ◽  
Electromechanical Responses ◽  
Electromechanical Performance ◽  
New Type ◽  
Hybrid Actuation ◽  
Actuation Systems ◽  
Further Development

An electroactive polymer-ceramic hybrid actuation system (HYBAS) was recently developed. The HYBAS demonstrates significantly-enhanced electromechanical performance by utilizing advantages of cooperative contributions of the electromechanical responses of an electrostrictive copolymer and an electroactive single crystal. The hybrid actuation system provides not only a new type of device but also a concept to utilize different electroactive materials in a cooperative and efficient method for optimized electromechanical performance. In order to develop an effective procedure to optimize the performance of a hybrid actuation system (HYBAS), a theoretical model has been developed, based on the elastic and electromechanical properties of the materials utilized in the system and on the configuration of the device. The model also evaluates performance optimization as a function of geometric parameters, including the length of the HYBAS and the thickness ratios of the constituent components. The comparison between the model and the experimental results shows a good agreement and validates the model as an effective method for the further development of high performance actuating devices or systems for various applications.

Adhesive and composite properties of LARCTM-8515 polyimide

1995 ◽  
Vol 7 (1) ◽  
pp. 11-21 ◽  
Author(s):  
B J Jensen ◽  
T H Hou ◽  
S P Wilkinson
Keyword(s):  
Composite Laminates ◽  
High Performance ◽  
Molar Ratio ◽  
Aromatic Polyimide ◽  
Aerospace Applications ◽  
Short Beam ◽  
Beam Shear ◽  
Open Hole ◽  
Biphenyltetracarboxylic Dianhydride ◽  
Langley Research Center

LARCTM-8515 (Langley Research Center-8515) is an aromatic polyimide based on 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) and an 85:15 molar ratio of 3,4'-oxydianiline (3,4'-ODA) and 1,3-bis(3-amnophenoxy)benzene (APB). This material is currently under evaluation as an adhesive and composite matrix resin for use in high-performance aerospace applications. The synthesis and development of the copolymer as well as studies of the effect of molecular weight on properties will be discussed. LARCTM-8515 has been evaluated as an adhesive, and titanium to titanium tensile shear strengths will be presented. Unidirectional prepreg was' made utilizing the Langley multipurpose tape machine. and the thermal and rheological properties and the solvent/volatile depletion rates of the poly(amide acid)/NMP resin system were determined. This information was used to successfully design a moulding cycle for composite preparation. Composite laminates were moulded under 200 psi, which consistently yielded good consolidation quality as measured by C-scan, acid digestion and optical photomicrography. Composite mechanical properties measured included short-beam shear strength and flexural strength and modulus at RT, 93, 150 and 177C. and compression strength (ITRI) and open hole compression (OHC) strength at RT and 177 C (wet).

Robustness versus Performance Assessment for Different Gamma-TiAl Processing Routes

2011 ◽  
Vol 1295 ◽  
Author(s):  
Marc Thomas
Keyword(s):  
High Performance ◽  
Cost Effective ◽  
Processing Route ◽  
Transportation Industry ◽  
Tial Alloys ◽  
Alternative Processing ◽  
Aerospace Applications ◽  
Robust Processing ◽  
Processing Techniques ◽  
Robust Process

ABSTRACTOne of the main driving force for the development of advanced structural materials is weight saving especially in the transportation industry in order to reduce CO2 emission. The utilization of gamma aluminides, as good candidates for aerospace applications, is strongly related to the development of a cost-effective and robust processing route, as far as possible. It is well established that the processing route, i.e. cast, wrought or PM, has a dramatic effect on the microstructure and texture of gamma-TiAl alloys. Therefore, significant microstructural variations through post-heat treatments coupled with compositional modifications can only guarantee a proper balance of desired properties. However, a number of metallurgical factors during the processing steps can contribute to some scattering in properties. This review will highlight several critical process variables in terms of the resulting g-TiAl microstructures. Of primary importance is the as-cast texture which is difficult to control and may contribute to prefer some alternative processing routes to ensure a better repeatability in mechanical results. Some innovative processing techniques for controlling the structure will then be presented. The main point which will be discussed in this paper is whether an approach leading to a robust process would not be at the expense of the high performance of the structural material.

High-performance near-infrared photodetectors based on C3N quantum dots integrated with single-crystal graphene

2021 ◽  
Author(s):  
Yun Zhao ◽  
Xiaoqiang Feng ◽  
Menghan Zhao ◽  
Xiaohu Zheng ◽  
Zhiduo Liu ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Electric Field ◽  
Single Crystal ◽  
High Performance ◽  
Near Infrared ◽  
Fast Response ◽  
Local Electric Field ◽  
Infrared Photodetectors ◽  
Photocurrent Response

Employing C3N QD-integrated single-crystal graphene, photodetectors exhibited a distinct photocurrent response at 1550 nm. The photocurrent map revealed that the fast response derive from C3N QDs that enhanced the local electric field near graphene.

scholarly journals Intrinsic Self-Healing Epoxies in Polymer Matrix Composites (PMCs) for Aerospace Applications

Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 201
Author(s):  
Stefano Paolillo ◽  
Ranjita K. Bose ◽  
Marianella Hernández Santana ◽  
Antonio M. Grande
Keyword(s):  
High Performance ◽  
Polymer Matrix Composites ◽  
Critical Issue ◽  
General Description ◽  
Self Healing ◽  
Matrix Composites ◽  
Testing Procedures ◽  
Aerospace Applications ◽  
Polymer Properties ◽  
Healing Efficiency

This article reviews some of the intrinsic self-healing epoxy materials that have been investigated throughout the course of the last twenty years. Emphasis is placed on those formulations suitable for the design of high-performance composites to be employed in the aerospace field. A brief introduction is given on the advantages of intrinsic self-healing polymers over extrinsic counterparts and of epoxies over other thermosetting systems. After a general description of the testing procedures adopted for the evaluation of the healing efficiency and the required features for a smooth implementation of such materials in the industry, different self-healing mechanisms, arising from either physical or chemical interactions, are detailed. The presented formulations are critically reviewed, comparing major strengths and weaknesses of their healing mechanisms, underlining the inherent structural polymer properties that may affect the healing phenomena. As many self-healing chemistries already provide the fundamental aspects for recyclability and reprocessability of thermosets, which have been historically thought as a critical issue, perspective trends of a circular economy for self-healing polymers are discussed along with their possible advances and challenges. This may open up the opportunity for a totally reconfigured landscape in composite manufacturing, with the net benefits of overall cost reduction and less waste. Some general drawbacks are also laid out along with some potential countermeasures to overcome or limit their impact. Finally, present and future applications in the aviation and space fields are portrayed.

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