AFP mandrel development for composite aircraft fuselage skin

Deepak Kumar,Myung-Gyun Ko,Rene Roy,Jin-Hwe Kweon,Jin-Ho Choi,Soon-Kwan Jeong,Jin-Woo Jeon,Jun-Su Han 한국항공우주학회 2014 International Journal of Aeronautical and Space Sc Vol.15 No.1

Automatic fiber placement (AFP) has become a popular processing technique for composites in the aerospace industry, due to its ability to place prepregs or tapes precisely in the exact position when complex parts are being manufactured. This paper presents the design, analysis, and manufacture of an AFP mandrel for composite aircraft fuselage skin fabrication. According to the design requirements, an AFP mandrel was developed and a numerical study was performed through the finite element method. Linear static load analyses were performed considering the mandrel structure self-weight and a 2940 N load from the AFP machine head. Modal analysis was also performed to determine the mandrel’s natural frequencies. These analyses confirmed that the proposed mandrel meets the design requirements. A prototype mandrel was then manufactured and used to fabricate a composite fuselage skin. Material load tests were conducted on the AFP fuselage skin curved laminates, equivalent flat AFP, and hand layup laminates. The flat AFP and hand layup laminates showed almost identical strength results in tension and compression. Compared to hand layup, the flat AFP laminate modulus was 5.2% higher in tension and 12.6% lower in compression. The AFP curved laminates had an ultimate compressive strength of 1.6% to 8.7% higher than flat laminates. The FEM simulation predicted strengths were 4% higher in tension and 11% higher in compression than the flat laminate test results.

AFP mandrel development for composite aircraft fuselage skin

Kumar, Deepak,Ko, Myung-Gyun,Roy, Rene,Kweon, Jin-Hwe,Choi, Jin-Ho,Jeong, Soon-Kwan,Jeon, Jin-Woo,Han, Jun-Su The Korean Society for Aeronautical and Space Scie 2014 International Journal of Aeronautical and Space Sc Vol.15 No.1

Automatic fiber placement (AFP) has become a popular processing technique for composites in the aerospace industry, due to its ability to place prepregs or tapes precisely in the exact position when complex parts are being manufactured. This paper presents the design, analysis, and manufacture of an AFP mandrel for composite aircraft fuselage skin fabrication. According to the design requirements, an AFP mandrel was developed and a numerical study was performed through the finite element method. Linear static load analyses were performed considering the mandrel structure self-weight and a 2940 N load from the AFP machine head. Modal analysis was also performed to determine the mandrel's natural frequencies. These analyses confirmed that the proposed mandrel meets the design requirements. A prototype mandrel was then manufactured and used to fabricate a composite fuselage skin. Material load tests were conducted on the AFP fuselage skin curved laminates, equivalent flat AFP, and hand layup laminates. The flat AFP and hand layup laminates showed almost identical strength results in tension and compression. Compared to hand layup, the flat AFP laminate modulus was 5.2% higher in tension and 12.6% lower in compression. The AFP curved laminates had an ultimate compressive strength of 1.6% to 8.7% higher than flat laminates. The FEM simulation predicted strengths were 4% higher in tension and 11% higher in compression than the flat laminate test results.

Development of a robot OLP system for the continuous motion control of a mandrel in the radial braiding process

Jeongho Han,Jinwon Lee,Jeongsam Yang 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.6

The quality of a braid preform generated by the braiding process is affected by the movement path and speed. Previous studies have obtained an optimal movement path and an efficient speed profile of the mandrel, but no studies have considered robot kinematics for the mandrel’s motion, thereby causing errors occur during the braiding process. This study developed an off-line programming system that generates an optimal mandrel movement path to produce a high-quality preform based on the 3D curvature shape of the mandrel. This movement path is then converted into a robot command. The via-points for the robot path generation were extracted from the mandrel surface geometry. Afterwards, the process of generating a continuous motion and rearranging the via-points for radial braiding was performed. Continuous motion was created by separating the straight and curved paths, and the via-point rearrangement was applied depending on the change in speed.

복합재 분리형 맨드릴을 이용한 라이너 없는 복합재 추진제 탱크에 대한 시험 평가

이승윤 ( Seung Yun Rhee ),김광수 ( Kwangsoo Kim ),윤영하 ( Young-ha Yoon ),이무근 ( Moo-keun Yi ),김희철 ( Hee Chul Kim ) 한국복합재료학회 2023 Composites research Vol.36 No.2

추진제 탱크의 경량화를 위해 비강도가 우수한 탄소섬유 강화 복합재를 이용하여 라이너 없이 복합재 추진제 탱크를 제작하기 위한 연구를 수행하였다. 본 연구에서는 MEOP 1.7 MPa의 내압을 지탱할 수 있는 직경 800 mm의 복합재 추진제 탱크 축소형 시제를 설계하였고, 보스 또한 동일한 복합소재로 제작하여 무게를 줄였다. 라이너 없이 탱크를 제작하기 위해 분리형 맨드릴을 이용하였고, 맨드릴의 무게도 줄이고 경화 과정에서 맨드릴의 팽창을 줄여 치수안정성을 도모하기 위해 복합재로 맨드릴을 제작하였다. 맨드릴 상에 탄소섬유 직물 소재를 핸드레이업 공정으로 적층한 후 오토클레이브 경화 과정을 거쳐 시제품을 제작하였다. 시제품 제작 후, 상온 보증압 시험과 헬륨 기밀 시험, 그리고 상온 반복 내압 시험과 파열 시험을 수행하여 내압 강도 및 기밀 성능 요건을 충분히 만족함을 확인하였고 파열압에 대한 안전여유가 충분함을 확인하였다. 본 연구 결과를 발사체 연료탱크 개발에 적용함으로써 발사체 전체 경량화에 기여할 수 있고, 향후 극저온 성능까지 검증한다면 극저온 산화제탱크 제작에도 활용할 수 있을 것으로 기대된다. A linerless composite propellant tank was designed and manufactured by using the carbon fiber-reinforced composite materials which have superior strength-to-weight ratio in order to reduce weight of the tank. In this research, we designed a sub-scale composite propellant tank with a diameter of 800 mm to withstand an MEOP of 1.7 MPa. We manufactured the boss of the tank by using the same composite materials to reduce the thermal expansion difference between the boss and the secondary-bonded composite layers of the barrel in the cryogenic environment. We used the collapsible mandrel to manufacture the tank without any liner. The mandrel was made from epoxy-based composite tooling prepregs to reduce weight of the mandrel. We manufactured the test tanks by laying up the carbon fiber fabric prepregs manually on the mandrel and then applying the autoclave cure process. We performed a proof test, a helium tightness test, a repeated pressurization test, and a burst test in room temperature. The test results demonstrate that the proposed design and manufacture process satisfies all strength requirements as well as an anti-leakage requirement.

A New Approach for Applying a Non-conductive Mandrel in Electroforming of Complex Bellows-Shape

Pouya Fahimi Azad,Hamid Montazerolghaem 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.24 No.6

In this research, innovatively a flexible non-conductive polymer mandrel by applying graphite was used instead of conventional metal mandrels. To achieve a uniform shell thickness, a helical anode instead of usual flat anode and pulse reverse current instead of constant current were utilized. In this research, the effects of parameters such as current, pulse-forward time, pulse-reverse time on copper bellows-shape parts using pulse-reverse current in order to obtain proper thickness uniformity and hardness was investigated. To optimize the electroforming parameters, Response Surface Method (RSM) was applied. The optimum pulse-reverse and pulse-forward time for the set of parameters used in the experiments was determined to be I = 2A, TF = 8 ms and TR = 3.5 ms. Consequently, results showed that the type of current had a dominant effect on the uniformity of the copper bellows-shape parts on the non-conductive mandrel and the pules-reverse time played a significant role in obtaining efficient mechanical properties.

Sagnac형 광섬유 센서를 이용한 중공 원통형 맨드릴의 재료 및 설치 방향에 따른 음압 감지 변화 연구

이종길(Lee, Jong-Kil) 한국소음진동공학회 2012 한국소음진동공학회 논문집 Vol.22 No.7

In this paper, sound pressure sensitivity of the fiber optic acoustic sensor according to sensor direction and mandrel material were investigated experimentally. Three different directions were selected as stand, lay, and hole. Hollow cylinder type mandrel dimension is 30 mm in outer diameter, 45 mm in length, and 2 mm in thickness, and about 50 m optical fibers were wounded on the surface of the mandrel. Non-directional sound speaker was used as a sound source. Sagnac interferometer and single mode fiber, a laser with 1,550 nm in wavelength, $2{\times}2$ coupler were used. Based on the experimental results, lay direction's sensitivity is the highest in the frequency range of 2 kHz~4 kHz. 'PTFE+carbon' material is more sensitive than PTFE in the frequency range of 5 kHz~20 kHz. Sound pressure detection sensitivity depends on the mandrel direction and material under certain frequency.

Free Mandrel에 의한 Metal 스피닝 기술

이태호(Tae-Ho Lee) 한국추진공학회 2010 한국추진공학회 학술대회논문집 Vol.2010 No.11

기존의 재래식, 전단, 튜브 스피닝이 모두 축대칭 제품의 형상화된 맨드릴을 사용하여 가공하여 왔다. 이러한 고전적 기법에서 한걸음 더 나아가 비축대칭, 열처리를 동반한 스피닝, 맨드릴이 자유로운 새로운 공법이 시도되고 있다. 본 조사에서는 주로 자유 맨드릴 공법에 대하여 동향을 조사하였다. This paper investigates mainly the new free mandrel technology of the metal spinning. Although the classical spinning, so called conventional, shear, tube spinning, uses the axisymmetric shaped mandrel(which is same inner shape of the final product), new technology does not use it.

스플라인 맨드릴 플로우포밍을 위한 롤러 가공 깊이 최적화 연구

홍승우,원권희,장형석,윤승민,현승균,김상열 대한기계학회 2023 大韓機械學會論文集A Vol.47 No.4

Flow forming is a metal forming method that forms a thick circular preform whose thickness and length are determined by its rotation and the two-dimensional motion of the rollers used. In this study, the optimal conditions for the forming depth for splined mandrel flow forming were obtained by the comparative analysis of actual forming data and analyzed data obtained from the flow forming process of a wet clutch housing of a transmission. It required a structure that can transmit a high torque and achieve mechanical reliability owing to the characteristics of agricultural tractors. The large forming load generated during the flow forming process acted as a major factor in the abrasion of the rollers and the mandrel. Moreover, an imbalance was caused by the difference between the loads of the three rollers, producing product defects. Therefore, the forming depth of the rollers was optimized as a variable using the finite element method to minimize the load applied to each roller and determine the balanced condition for the loads of the three rollers. The results of the forming depth analysis yielded forming depths of 4.2 mm, 2.4 mm, and 2.2 mm for the A, B, and C rollers, respectively. These results were confirmed by comparative verification with actual forming data. 플로우포밍은 프리폼의 회전과 롤러의 2차원 운동을 통해 두꺼운 원형 프리폼을 얇고 길게 성형하는 금속 가공법 중 하나이다. 본 연구는 농기계 트렉터의 특성상 높은 토크를 전달할 수 있는 구조와 기계적 신뢰성이 요구되는 변속기의 습식 클러치 하우징을 성형하는 플로우포밍 공정에서 실제 가공 데이터와 해석 데이터를 비교분석을 통하여 가공 깊이 최적 조건을 구하였다. 플로우포밍 공정 중 발생하는 큰 성형 하중은 롤러와 맨드릴의 마멸에 주 인자로 작용하며, 3개의 롤러의 하중 차이로 불균형이 발생하여 제품 결함의 원인이 된다. 따라서 맨드릴고 각 롤러에 작용 하중을 최소화시키고, 3개의 롤러의 부하를 균형 있는 조건을 찾기 위하여 유한요소법을 이용하여 롤러의 가공 깊이를 변수로 최적화하였다. 가공 깊이 해석 결과는 A 롤러 4.2 mm, B 롤러 2.4 mm, C 롤러 2.2 mm로 나타나며, 실제 성형공정 데이터와 비교검증을 통하여 확인하였다.

관입식 복합 통수능 시험기의 개발과 적용성

유남재(Yoo Nam Jae),김동건(Kim Dong Gun),박병수(Park Byung Soo),전상현(Jun Sang Hyun) 대한토목학회 2008 대한토목학회논문집 C Vol.28 No.5

본 연구에서는 Plastic Board Drain(PBD)이 타설된 지반의 압밀거동 특성을 파악하고, 배수재 통수능력을 알아보기 위하여 현장의 타설조건을 실험실에서 모사할 수 있는 관입식 복합 통수능 시험기를 개발하였다. 개발된 시험기는 배수재를 타설하고 교란된 시료를 투기하는 기존 방법과 달리, 예비압밀로 시료를 조성한 후 mandrel과 관입장치를 이용하여 PBD를 지반에 타설하도록 고안하였다. 개발된 관입식 복합 통수능 시험기의 적용성을 평가하기 위하여 기존 복합 통수능 시험을 함께 실시하여 결과를 분석하였다. 실험 결과, 기존 방법은 시료 전체의 교란에 의해 압밀이 지연되는 현상으로 나타났으며, 시료의 불균질성 등에 의해 배수재 변형도 국부적으로 발생하였다. 이로 인허여 기존 시험법에 의한 통수능력은 예상치 보다 다소 크게 산정되는 경향을 보였으며, 관입식 방법에 의해 현장조건과 유사하게 통수능력을 분석할 수 있을 것으로 판단되었다. The discharge capacity testing apparatus using penetration method, being able to simulate in laboratory the condition of embedding plastic board drains in field, was developed to investigate consolidation characteristics of ground and to figure out discharge capacity of drains. The developed apparatus with a mandrel and penetrating device was designed to insert PBD into the ground prepared by previously applied pressure, being different from the conventional testing method that the drain was installed and the ground material was poured subsequently. Discharge capacity tests with the conventional apparatus as well as the newly developed one were performed to assess the applicability of the latter. As a result of tests, the conventional method showed delayed consolidation due to overall disturbance of ground and local deformation of drain caused by inhomogeneity of ground. Therefore discharge capacity of drain with the conventional apparatus was measured more or less larger than the expected values whereas discharge capacity with new one could be measured similar to the actual value in field.

전주기술을 이용한 로터리스크린 제조에 관한 연구

권혁홍,박상호 대진대학교 2004 大眞論叢 Vol.11 No.-

To simple the manufacturing process of rotary screen, this study was adopted electroforming technology and produced silicon rubber mandrel. Furthermore, to indicate the optimal condition for the acquisition of high-qualified rotary screen product, the experiment was executed with pH, time, sulfamate nickel solution according to density which were the main factors to decide the condition, then compared it with the product made by original "S" Company in Holland. As a result, the figure of Hole was more obvious and correct. Also the open size increased more than 2-3%.