• Journal of Aerospace System Engineering
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• v.1 no.2
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• pp.13-20
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• 2007

Structural qualification plan (SQP) for aerospace vehicle is based on material certification methodology, which must be approved by certification authority. It is internationally required to use of statistically based material allowables to design aerospace vehicles with aerospace materials. In order to comply with this regulation, it is necessary to establish relatively large amount of database, which increases test costs and time. Recently NASA/FAA develop the new methodology which results in cost, time, and risk reduction, and satisfies the regulation at the same time. This paper summarizes the certification methodology of materials system as a part of structural qualification plan (SQP) of aerospace vehicles and also thermal management of the vehicle system, like thermal protection materials system and thermally conductive material system. Materials design allowable was determined using this method for a carbon/epoxy composite material.

• International Journal of Aerospace System Engineering
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• v.10 no.1
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• pp.14-24
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• 2023

The materials applied to the aircraft fuselage, parts, and components must be verified by relative authorities in accordance with the procedures set by the airworthiness authority to achieve the aircraft type certification. There are no examples of domestic composite materials which were verified in order to be applied to aircraft structure. In this study, the composite material certification system of NCAMP, an American composite material standard certification organization, was reviewed and used as the fundamentals of the first aerospace composite material certification system in ROK(Fig 2,8). Also updated material certification documents were developed and confirmed by material certification engineers and inspectors. This aerospace composite material qualification system is intended to modernize the material certification system for AAM(Advanced Air Mobility) as well as aircraft and to enhance the understanding of related technicians and inspectors.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1479-1482
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• 2009

Compared with tilt transfer wet station, vertical etching system has a variety of advantages that are 50% space savings, higher throughput, fairly good etch uniformity over an entire glass for thin film transistor application. The aim of the present work is to study on a vertical etching system to improve the process factors. The computational fluid dynamics analysis is used to demonstrate the change of the etch uniformity as a function of tilt angle of the glass substrate.

• International Journal of Aeronautical and Space Sciences
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• v.16 no.1
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• pp.28-40
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• 2015

This paper aims to address the intelligent active vibration control problem of a flexible rectangular plate vibration involving parameter variation and external disturbance. An adaptive sliding mode (ASM) MIMO control strategy and smart piezoelectric materials are proposed as a solution, where the controller design can deal with problems of an external disturbance and parametric uncertainty in system. Compared with the current 'classical' control design, the proposed ASM MIMO control strategy design has two advantages. First, unlike existing classical control algorithms, where only low intelligence of the vibration control system is achieved, this paper shows that high intelligent of the vibration control system can be realized by the ASM MIMO control strategy and smart piezoelectric materials. Second, the system performance is improved due to two additional terms obtained in the active vibration control system. Detailed design principle and rigorous stability analysis are provided. Finally, experiments and simulations were used to verify the effectiveness of the proposed strategy using a hardware prototype based on NI instruments, a MATLAB/SIMULINK platform, and smart piezoelectric materials.

• Composites Research
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• v.28 no.6
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• pp.402-407
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• 2015

It is well known that the polymer matrix composite materials have good specific strength, making them appropriate for use in transport vehicle. Since the property of composite materials can be obtained only after manufacturing parts, the property depends on greatly on the fabrication process, which is different from metallic system. Therefore, in order to use composite materials for aircraft, the certifying agency requires a robust database with extensive tests and proof of the process unlike metals. Recently developed material qualification methodology by NCAMP (National Center for Advanced Materials Performance) has been accepted by FAA and EASA and can be applied to type certificate reducing time and cost of developing a composite materials database for aircraft application. This paper summarizes a study to establish the composite materials database to apply the NCAMP methodology to composite materials characterization for composite aircraft and to provide the effective materials database through Aerospace Composite Materials Data Center to be approved by Korea Civil Aviation Certification Agency.

• Journal of Aerospace System Engineering
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• v.7 no.4
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• pp.55-61
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• 2013

In recent years, NASA, FAA and the aerospace industry, through MIL-HDBK-17 and the NASA-conceived AGATE(Advanced General Aviation Transport Experiments) program, have worked together to reduce the qualification burden imposed on individual aircraft manufacturers. AGATE is one of the most successful public/private cost-haring partnerships ever conceived, bringing together academia, the FAA, other government agencies and industry to develop affordable new technologies and accompanying industry standards and certification methods. In 2005, NASA established NCAMP(National Center for Advanced Materials Performance) with the purpose of refining and enhancing the AGATE process to a self-sustaining level to serve the entire aerospace industry in partnership with CMH-17, FAA, and SAE. In this paper, I will introduce briefly NCAMP process and explain its organization structure and core NCAMP documents. This paper can provide some help in establishing our certification system for composite materials where the NCAMP process is expected to be the most good model.

• Journal of Aerospace System Engineering
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• v.9 no.3
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• pp.8-11
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• 2015

Since the late 1990's, FAA, NASA and the aerospace industry have worked together to develop the sharing system of the composite material qualification databases which were obtained through the standardized fabrication and testing procedures. The result was what is now known as the AGATE(Advanced General Aviation Transport Experiments) or NCAMP(National Center for Advanced Materials Performance) methodology, a more cost-effective concept that shifts the major responsibility for qualification and testing from the aircraft manufacturer to the material supplier. The properties of composite materials are largely dependent on the testing as well as the raw material properties and the manufacturing process including the process control parameters. Thus it is important in the composite material qualification to comply with the standardized testing procedures. In this paper, I will describe the standardized witness methodologies of certification engineers to reduce the effect of testing variability within the qualification data.

• Journal of Aerospace System Engineering
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• v.10 no.3
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• pp.63-69
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• 2016

The properties of composite materials, when compared to those of metallic materials, are highly variable due to many factors including the batch-to-batch variability of raw materials, the prepreg manufacturing process, material handling, part-fabrication techniques, ply-stacking sequences, environmental conditions, and test procedures. It is therefore necessary to apply reliable statistical-analysis techniques to obtain the design allowables of composite materials. A new composite-material qualification process has been developed by the Advanced General Aviation Transport Experiments (AGATE) consortium to yield the lamina-design allowables of composite materials according to standardized coupon-level tests and statistical techniques; moreover, the generated allowables database can be shared among multiple users without a repeating of the full qualification procedure by each user. In 2005, NASA established the National Center for Advanced Materials Performance (NCAMP) with the purpose of refining and enhancing the AGATE process to a self-sustaining level to serve the entire aerospace industry. In this paper, the statistical techniques and procedures for the generation of the allowables of aerospace composite materials will be discussed with a focus on the pooling-across-environments method.

• Journal of Positioning, Navigation, and Timing
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• v.2 no.1
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• pp.19-31
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• 2013

It is well known that the accident of vehicles carrying hazardous materials incurs huge losses economically and socially. To detect and respond rapidly against the accident of a vehicle carrying hazardous materials, it is essential to estimate the relative navigation information between the forward tractor module and the backward trailer module of the vehicle reliably and accurately. In this paper, a precise relative positioning system based on GPS is designed, implemented, and evaluated as a prerequisite to design an effective relative navigation system for the vehicle carrying hazardous materials. An experiment using field-collected 10 Hz real GPS measurements showed that the designed relative positioning system achieves 22 cm accuracy within 15 epochs by float solutions. Also, it was found that cm-level integer solutions can be generated reliably after the quick convergence of float solutions.

• International Journal of Aerospace System Engineering
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• v.3 no.1
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• pp.1-4
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• 2016

Functionally graded materials (FGMs) are becoming very popular in various industries due to their effectiveness of the utilization of their constituent elements. However, the modelling of these materials is difficult due to the complex nature of variation of material properties across the thickness. Many shear deformation theories have been developed and employed for the analysis of such functionally graded plates (FGPs). A recently developed inverse hyperbolic shear deformation theory has been successfully employed by Grover et al. [1] for the analysis of laminated composites and sandwich plates. The objective of the study is to obtain finite element solution for the structural analysis of functionally graded plates using inverse hyperbolic shear deformation theory. Finite element analysis facilitates the analysis of complex problems such as functionally graded plates with different boundary conditions and different loadings.