NASA SBIR abstracts of 1991 phase 1 projects

The objectives of 301 projects placed under contract by the Small Business Innovation Research (SBIR) program of the National Aeronautics and Space Administration (NASA) are described. These projects were selected competitively from among proposals submitted to NASA in response to the 1991 SBIR Program Solicitation. The basic document consists of edited, non-proprietary abstracts of the winning proposals submitted by small businesses. The abstracts are presented under the 15 technical topics within which Phase 1 proposals were solicited. Each project was assigned a sequential identifying number from 001 to 301, in order of its appearance in the body of the report. Appendixes to provide additional information about the SBIR program and permit cross-reference of the 1991 Phase 1 projects by company name, location by state, principal investigator, NASA Field Center responsible for management of each project, and NASA contract number are included

탄소/에폭시 수리를 위한 복합재 프린터

학위논문(박사)--서울대학교 대학원 :공과대학 기계항공공학부,2020. 2. 안성훈.Carbon-fiber composites are widely used in airplanes, and the development of electric vehicles has spurred demand as interest in light materials has increased concurrently. Thus, researchers have begun to study how users of these products repair them, but the properties of fiber composites make it difficult to measure the level of destruction in repaired areas. The repair process is usually based on hand-lay-up. The success of this method depends on the repairer's proficiency, and it takes much labor and time to cut carbon fibers according to the size and shape of the repair part. Furthermore, the post-curing process also takes a long time, regardless of the size of the repair area. This can lead to a large amount of waste when repairing small components, such as the surfaces of car parts. Another issue is how best to evaluate the repaired area. If monitoring the life cycle or deformation of the component is conducted, even after the repair has been carried it, the user can anticipate and prepare for repairs based on strain sensor data. Studies of large equipment, such as conventional airplanes, and the use of automated tape layering (ATL) to make large carbon composite materials have been actively underway since 2016. However, most previous research has been aimed at producing large carbon-fiber composite materials and reducing the ᅮ waste and labor required for repair processes. However, there are no automated processes for smallscale repairs. Various small devices, from vehicles to mobile phones, use composites and thus require appropriate repair processes. Studies focusing on these issues are still lacking. In this study, we developed a rapid curing carbon-fiber composite printer. This can achieve a uniform fiber composite by automating the fiber laying method. A rapid curing device using Joule heat is used for local repairs. The repair time is reduced by mounting the rapid curing device on the printer. The proposed printing system is validated by comparing the recovery rates of undamaged specimens and double-lap repaired specimens. These repaired samples achieve uniform quality following repeated repair, and are thus superior to conventional hand-lay-up repaired samples. The use of the rapid curing system improved the recovery rate by 93% or more in the double lap test. As mentioned previously, the variables used to describe the repair performance, which may vary depending on the technician's proficiency, are stabilized under our system. The rapid curing is also optimized by mounting a feedback system between the temperature and electric power. This achieves uniform recovery rates, regardless of user proficiency. Non-destructive testing is also possible if we attach highly sensitive nanoparticle sensors to the device. The quality of the repair is assessed based on the life cycle and deformation of adhesive repair patches, which are evaluated using the proposed sensors. In this study, we propose the use of a rapid curing carbon composite printer and nanoparticle sensors. We expect that the composite printer developed in our research can be used to support the development of carbon composite applications in industries such as electric vehicles and airplanes.탄소 섬유 복합재의 수요는 비행기 산업 및 풍력 발전 산업 등에서 많이 사용되어 왔으며, 전기차의 발전으로 인해 경량소재에 대한 관심 또한 증가하면서 더욱 많은 수요가 발생하였다. 이에 따라 이 제품들을 사용하는 사용자들의 수리방법에 대한 연구가 진행되어왔으며, 섬유 복합재의 특성상 수리된 부위의 파괴수준을 측정하기 어렵고, 이를 확인한 후에도 수리과정이 작업자의 손을 이용한 작업이 주된 방법이다. 이 방법은 수리자의 숙련도에 크게 수리의 성능이 좌우되는 방법이며, 수리부위의 크기와 형태에 따라 탄소 섬유를 재단하는데 큰 노동과 시간이 들어간다. 또한 복합재의 다른 특성인 후경화 과정은 수리과정에서 긴 시간을 요구하며, 이는 수리 부위의 크기와 상관없이 긴 시간이 걸리기 때문에 자동차 부분 파손 혹은 휴대폰 외관 수리와 같은 작은 파트를 수리하는 부분에 있어 큰 낭비가 될 수 있다. 수리를 완료한 이후에도 이 수리부의 수명이나 변형을 측정함으로써, 사용자가 파손을 예측하고 대비하고 정도에 따라 수리과정을 준비할 방법 또한 필요하다. 본 연구에서는 위와 같은 문제들에 대하여 사람의 손으로 진행해야 하는 부분을 자동화함으로써 변수를 통합 및 안정화하고, 긴 시간을 차지하는 후경화를 국지적 주울열을 통한 급속 경화 장치를 추가함으로써 급속 경화 탄소 섬유 복합재 프린터를 개발하였다. 기존의 비행기나 대형 탄소복합재를 만들기 위한 Automated tape laying (ATL) 과 같은 대형 장비들에 대한 연구들이 2016 부터 활발히 진행되었으나, 기존 연구의 대부분은 대형 탄소 섬유 복합재를 제작하는 것을 목적으로 진행하고 있어, 후경화의 단축에 대한 연구수행과 소규모성의 수리를 위한 자동화 공정에 대한 연구는 여전히 부족한 실정이다. 또한 본 연구의 국지적 수리에 적합한 주울열을 통한 급속 경화 장치가 적용된 사례는 없다. 이와 같이 본 연구에서 제안된 프린팅 시스템을 이용하여 양면 접착 방식의 수리 시편을 만들어 기존 미파괴 시편과의 파단강도에 따른 비율을 회복률이라고 정의하였다. 또한 실험을 통해 회복률을 확인하였고, 프린팅을 통한 수리 시편은 인장강도 기준으로 80% 이상 수준을 달성하였고 급속 경화 시스템을 추가한 시편의 경우는 짧은 구간에서 더 높은 접착력을 보이면서 93%이상 회복률로 향상되었다. 또한 앞서 제시한 바와 같이 수리자의 숙련도에 따라 변경될 수 있는 수리 성능에 대한 변수를 규격화 하였으며, 온도와 전력량 간의 피드백 시스템을 형성하여 급속 경화 또한 최적화함으로써 사용자의 숙련도와 상관없이 균일한 회복률을 얻을 수 있는 효과를 얻었고 이에 접착 수리 패치의 수명과 대변형과 같은 수리파손 예방을 위한 나노입자 센서를 부착하고 무선통신 시스템을 적용함으로써 비파괴 검사 또한 진행할 수 있도록 하였다. 본 연구에서 제안된 급속 경화 탄소 복합재 프린터와 이를 검사할 수 있는 시스템의 원리를 응용한 기술은 발전될 탄소 섬유를 이용한 전기차 혹은 휴대기기 시장 등 산업적 응용 분야 확장에 기여할 것으로 기대된다.1 CHAPTER 1. INTRODUCTION 1 1.1 OVERVIEW 1 1.2 CARBON FIBER REINFORCED PLASTIC (CFRP) 5 1.3 CFRP REPAIR 5 1.4 THE GOAL OF THIS RESEARCH 7 1.5 OUTLINE OF DISSERTATION 9 2 CHAPTER 2. BACKGROUND 11 2.1 DEMAND FOR CFRP 11 2.2 BONDED PATCH REPAIR 13 2.3 STRUCTURAL HEALTH MONITORING (SHM) 19 3 CHAPTER 3. DESIGN AND FABRICATION 21 3.1 DIRECT CARBON PRINTING SYSTEM 21 3.1.1 Overview of printing system 21 3.1.2 Fiber feeding component 26 3.1.3 Epoxy feeding component 30 3.2 RAPID CURING SYSTEM 32 3.2.1 Overview of rapid curing process 32 3.2.2 Modeling for rapid curing 33 3.2.3 Joule heating module 39 3.2.4 Electric-Thermal feedback module 44 3.3 HIGHLY SENSITIVE SENSOR PATCH FOR SHM 48 3.3.1 Aerodynamically focused nanoparticle (AFN) printing 48 3.3.2 Highly sensitive strain sensor 53 3.3.3 Design of sensor patch and communication system 57 4 CHAPTER 4. EVALUATION 64 4.1 EVALUATION OF PRINTED SAMPLE 64 4.2 EVALUATION OF DEGREE OF CURING VIA RAPID CURING 77 4.3 EVALUATION OF SHM VIA COMMUNICATION SYSTEM 84 5 CHAPTER 5. CONCLUSION 89 BIBLIOGRAPHY 91 요약 (국문초록) 99Docto

Aeronautical engineering: A continuing bibliography with indexes (supplement 231)

This bibliography lists 469 reports, articles, and other documents introduced into the NASA scientific and technical information system in September, 1988

NASA scientific and technical publications: A catalog of special publications, reference publications, conference publications, and technical papers, 1991-1992

This catalog lists 458 citations of all NASA Special Publications, NASA Reference Publications, NASA Conference Publications, and NASA Technical Papers that were entered into the NASA Scientific and Technical Information database during accession year 1991 through 1992. The entries are grouped by subject category. Indexes of subject terms, personal authors, and NASA report numbers are provided

NASA/USRA University Advanced Design Program Fourth Annual Summer Conference

The study topics cover a broad range of potential space and aeronautics projects which could be undertaken during a 20-30 year period beginning with the Space Station Initial Operating Configuration scheduled for the mid 1990's. Both manned and unmanned endeavors are embraced, and the systems approach to the design problem is emphasized. The student teams pursue the chosen problem during their senior year in a one or two semester capstone design course and submit a comprehensive written report at the conclusion of the project. Finally, student representatives from each of the universities summarize their work in oral presentations at the annual Summer Conference, held at one of the NASA centers and attended by the university faculty, NASA and USRA personnel, and aerospace industry representatives

Aeronautical Engineering: A continuing bibliography with indexes (supplement 188)

This bibliography lists 477 reports, articles and other documents introduced into the NASA scientific and technical information system in May 1985. The coverage includes documents on the engineering and theoretical aspects of design, construction, evaluation, testing, operation, and performance of aircraft (including aircraft engines) and associated components, equipment and systems

Fabricate 2020

Fabricate 2020 is the fourth title in the FABRICATE series on the theme of digital fabrication and published in conjunction with a triennial conference (London, April 2020). The book features cutting-edge built projects and work-in-progress from both academia and practice. It brings together pioneers in design and making from across the fields of architecture, construction, engineering, manufacturing, materials technology and computation. Fabricate 2020 includes 32 illustrated articles punctuated by four conversations between world-leading experts from design to engineering, discussing themes such as drawing-to-production, behavioural composites, robotic assembly, and digital craft

The 1992 Research/Technology report

The 1992 Research & Technology report is organized so that a broad cross section of the community can readily use it. A short introductory paragraph begins each article and will prove to be an invaluable reference tool for the layperson. The approximately 200 articles summarize the progress made during the year in various technical areas and portray the technical and administrative support associated with Lewis technology programs

Adaptive Robotic Chassis (ARC)

The ARC is a width adjusting agricultural robot and accommodates auxiliary functions for supporting crop production and maintenance. Easily interchangeable payloads and components provide a modular solution to perform focused crop surveying functions with the potential for herbicide distribution, weeding, and harvesting while driving through varying crop rows. The potential auxiliary functions will be implemented by future teams with this year\u27s effort being put toward finishing the physical chassis. The final product was successfully designed to weigh approximately 600 pounds targeting rolling speeds of0.90 fps to 2.30 fps with proof of concept shown in testing consisting of chain drive attached to wheels to show speeds are attainable as well as bench tests to show differential control capabilities

Proceedings of the Seventh Annual Summer Conference. NASA/USRA: University Advanced Design Program

The Advanced Design Program (ADP) is a unique program that brings together students and faculty from U.S. engineering schools with engineers from the NASA centers through integration of current and future NASA space and aeronautics projects into university engineering design curriculum. The Advanced Space Design Program study topics cover a broad range of projects that could be undertaken during a 20-30 year period beginning with the deployment of the Space Station Freedom. The Advanced Aeronautics Design Program study topics typically focus on nearer-term projects of interest to NASA, covering from small, slow-speed vehicles through large, supersonic passenger transports and on through hypersonic research vehicles. Student work accomplished during the 1990-91 academic year and reported at the 7th Annual Summer Conference is presented