Air Vehicle Integration and Technology Research (AVIATR). Task Order 0003: Condition-Based Maintenance Plus Structural Integrity (CBM+SI) Demonstration (September 2011 to March 2012)

In order to solve the problem of complicated electronic equipment structure, inadequate fault information, hard to predict the fault and the existing failure prediction method cannot predict the state of the electronic equipment and other issues directly, we propose a combination failure prediction methods of least squares support vector machine (LSSVM) and hidden Markov model (HMM) based on Condition Based Maintenance (CBM). First, according to sensitivity analysis to determine the circuit elements to be changed to set the circuit by changing the parameters of the different components degraded state; secondly, create a combination failure prediction model; Finally, the circuit state prediction. The results show that the proposed method can directly predict the different states of the circuit, so as to realize the fault state prediction of the electronic equipment directly, the prediction accuracy can reach 93.3%.

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Corrosion Sensor Development for Condition-Based Maintenance of Aircraft

International Journal of Aerospace Engineering ◽

10.1155/2012/684024 ◽

2012 ◽

Vol 2012 ◽

pp. 1-11 ◽

Cited By ~ 2

Author(s):

Gino Rinaldi ◽

Trisha Huber ◽

Heather McIntosh ◽

Les Lebrun ◽

Heping Ding ◽

...

Keyword(s):

Structural Integrity ◽

Chloride Ion ◽

Hydrogen Gas ◽

Condition Based Maintenance ◽

Ion Concentration ◽

Sensor Data ◽

Polymer Sensors ◽

Corrosion Sensor ◽

Commercial Off The Shelf ◽

Maintenance Schedules

Aircraft routinely operate in atmospheric environments that, over time, will impact their structural integrity. Material protection and selection schemes notwithstanding, recurrent exposure to chlorides, pollution, temperature gradients, and moisture provide the necessary electrochemical conditions for the development and profusion of corrosion in aircraft structures. For aircraft operators, this becomes an important safety matter as corrosion found in a given aircraft must be assumed to be present in all of that type of aircraft. This safety protocol and its associated unscheduled maintenance requirement drive up the operational costs of the fleet and limit the availability of the aircraft. Hence, there is an opportunity at present for developing novel sensing technologies and schemes to aid in shifting time-based maintenance schedules towards condition-based maintenance procedures. In this work, part of the ongoing development of a multiparameter integrated corrosion sensor is presented. It consists of carbon nanotube/polyaniline polymer sensors and commercial-off-the-shelf sensors. It is being developed primarily for monitoring environmental and material factors for the purpose of providing a means to more accurately assess the structural integrity of aerospace aluminium alloys through fusion of multiparameter sensor data. Preliminary experimental test results are presented for chloride ion concentration, hydrogen gas evolution, humidity variations, and material degradation.

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Structural integrity aspects of a lightweight civil unmanned air vehicle

International Journal of Structural Integrity ◽

10.1108/ijsi-11-2015-0055 ◽

2016 ◽

Vol 7 (6) ◽

pp. 773-787 ◽

Cited By ~ 1

Author(s):

Efstratios Giannakis ◽

George Savaidis

Keyword(s):

Material Properties ◽

Structural Integrity ◽

Aircraft Design ◽

International Standards ◽

Optimized Design ◽

Structural Elements ◽

Safety Factors ◽

Content Type ◽

Unmanned Air Vehicle ◽

Air Vehicle

Purpose The purpose of this paper is to focus on the finite element (FE) analyses undertaken for aerodynamically and structurally optimized design of a modern, lightweight civil unmanned air vehicle (UAV) made fully of composite materials. Design/methodology/approach The FE method has been applied to design and calculate the safety factors of all structural elements of the UAV. Fully parameterized design tools have been developed in the preliminary design phase, allowing automatic reshapes of the skin and the internal structural parts, wherever needed, to achieve optimal structural design, from the point of view of lightweight and structural integrity. Monotonic and fatigue tests have been performed on material specimens with various thicknesses and fibre textures, to verify the material properties used for the FE analyses. The load assumptions were in accordance with the valid international standards. Findings The material tests confirmed the validity of the material properties used within the FE calculations. The calculated safety factors were acceptable for all structural elements and components of the UAV. As a result, a lightweight, structurally optimized design has been achieved, considering the international, standardized specifications assumptions and fulfilling the safety requirements. Practical implications Design engineers may use the outcomes of this work as a guide to achieve optimal lightweight structures ensuring its operational strength using composite, lightweight materials. Originality/value A new, structurally optimized, lightweight aircraft design has been developed, able to accommodate heavy electronic payloads while being able to fly for over ten hours without refuelling. This medium altitude long endurance airplane can overview forests, seas and human trafficking autonomously and economically.

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Electron Beam Damage of Biomolecules Assessed by Energy Loss Spectroscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100069855 ◽

1978 ◽

Vol 36 (3) ◽

pp. 61-69

Author(s):

M. Isaacson ◽

M.L. Collins ◽

M. Listvan

Keyword(s):

Electron Microscopy ◽

Radiation Damage ◽

Structural Integrity ◽

Analytical Electron Microscopy ◽

High Dose ◽

Dose Rates ◽

Special Cases ◽

Analytical Electron ◽

Atom Migration ◽

Beam Damage

Over the past five years it has become evident that radiation damage provides the fundamental limit to the study of blomolecular structure by electron microscopy. In some special cases structural determinations at very low doses can be achieved through superposition techniques to study periodic (Unwin & Henderson, 1975) and nonperiodic (Saxton & Frank, 1977) specimens. In addition, protection methods such as glucose embedding (Unwin & Henderson, 1975) and maintenance of specimen hydration at low temperatures (Taylor & Glaeser, 1976) have also shown promise. Despite these successes, the basic nature of radiation damage in the electron microscope is far from clear. In general we cannot predict exactly how different structures will behave during electron Irradiation at high dose rates. Moreover, with the rapid rise of analytical electron microscopy over the last few years, nvicroscopists are becoming concerned with questions of compositional as well as structural integrity. It is important to measure changes in elemental composition arising from atom migration in or loss from the specimen as a result of electron bombardment.

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Structural integrity after cold storage of human epidermal model in hypothermosol: A correlative ultrastructural and fluorescent assay

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100169080 ◽

1994 ◽

Vol 52 ◽

pp. 270-271

Author(s):

Henry H. Eichelberger ◽

John G. Baust ◽

Robert G. Van Buskirk

Keyword(s):

Cold Storage ◽

Structural Integrity ◽

Culture Media ◽

Cell Structure ◽

Natural State ◽

Sodium Cacodylate ◽

Ruthenium Tetroxide ◽

Cacodylate Buffer ◽

Before And After

For research in cell differentiation and in vitro toxicology it is essential to provide a natural state of cell structure as a benchmark for interpreting results. Hypothermosol (Cryomedical Sciences, Rockville, MD) has proven useful in insuring the viability of synthetic human epidermis during cold-storage and in maintaining the epidermis’ ability to continue to differentiate following warming.Human epidermal equivalent, EpiDerm (MatTek Corporation, Ashland, MA) consisting of fully differentiated stratified human epidermal cells were grown on a microporous membrane. EpiDerm samples were fixed before and after cold-storage (4°C) for 5 days in Hypothermosol or skin culture media (MatTek Corporation) and allowed to recover for 7 days at 37°C. EpiDerm samples were fixed 1 hour in 2.5% glutaraldehyde in sodium cacodylate buffer (pH 7.2). A secondary fixation with 0.2% ruthenium tetroxide (Polysciences, Inc., Warrington, PA) in sodium cacodylate was carried out for 3 hours at 4°C. Other samples were similarly fixed, but with 1% Osmium tetroxide in place of ruthenium tetroxide. Samples were dehydrated through a graded acetone series, infiltrated with Spurrs resin (Polysciences Inc.) and polymerized at 70°C.

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