• Transactions of the Korean hydrogen and new energy society
• /
• v.29 no.2
• /
• pp.190-196
• /
• 2018

Carbon fiber/epoxy composites are typical brittle materials and have low impact properties. Recently, it is important to investigate impact characteristics of carbon fiber composites because of increasing use as automobile parts and high pressure hydrogen vessels of fuel cell electric vehicles for light weight. In this study, the low velocity impact properties of carbon fiber/epoxy composites fabricated by a filament winding method are studied. The low velocity impact properties were measured by performing tests according to ASTM D7136. The low velocity impact simulations were carried out using commercial structural analysis software, Abaqus. The absorbed energy and the delamination shapes were compared between the experimental and simulation results. The numerical analysis method showed that the absorbed energy decreased with the reduced number of cohesive elements in the composite models.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.39 no.5
• /
• pp.491-497
• /
• 2015

This paper reports an experimental study for evaluating the effect of temperature on the mode I, mode II and mixed-mode interlaminar fracture toughness of adhesive joints with a curved cross-section of filament-wound dome-separated composite pressure vessel. Mode I and mixed-mode interlaminar fracture toughness were evaluated using DCB specimens, while mode II interlaminar fracture toughness was determined using ENF specimens. $[{\pm}10^{\circ}]_6$, $[{\pm}27^{\circ}]_6$ and ($[{\pm}10^{\circ}]_3/FM73/[{\pm}27^{\circ}]_3$) winding specimens with the curved cross-section were considered. In-situ temperature environments were simulated with a range of $-30^{\circ}C-60^{\circ}C$ using an environmental chamber and furnace. Experimental results on the effect of temperature indicate that interlaminar fracture toughness tends to be high at low temperature and is degraded with increase in temperature. For specimen types, it was found that interlaminar fracture toughness of $[{\pm}10^{\circ}]_3/FM73/[{\pm}27^{\circ}]_3$ winding specimens considered as adhesive joints of dome and helical part was higher than other specimens.

• 한국전기화학회:학술대회논문집
• /
• 2005.07a
• /
• pp.201-206
• /
• 2005

본 연구는 기 개발 완료된 천연가스차량용 200bar급 Type 3 복합재 압력용기를 개발로 축척된 핵심요소기술과 실질적인 경험을 바탕으로 수소연료전지 차량에 탑재할 350bar급 Type 3 복합재 압력용기에 대한 설계/해석과 시험평가의 핵심적인 사항을 고찰하였다. 설계/해석에는 350bar급 Type 3 복합재 압력용기에 대한 3차원 비선형 유한요소 모델링 및 해석기법이 제시되었고, 설계된 라이너형상과 와인딩 패턴을 이용하여 필라멘트 와인딩 공법으로 1차시제품을 제작하였다. 제작된 시제품에 대하여 파열시험 및 반복피로시험을 수행하여 설계/해석 기법의 타당성을 검증하였다.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.05a
• /
• pp.656-660
• /
• 2002

The fiber reinforced composite material is widely used in the multi-industrial field where the weight reduction of the infrastructure is demanded because of their high specific modulus and specific strength. Pressure vessels using this composite material in comparison with conventional metal vessels can be applied in the field where lightweight and the high pressure is demanded from the defense and aerospace industry to rocket motor case due to the merits which are energy curtailment by the weight reduction and decrease of explosive damage precede to the sudden explosion which is generated by the pressure leakage condition. In this paper, for nonlinear finite element analysis of E-glass/epoxy filament winding composite pressure vessel receiving an internal pressure, the standard interpretation model is developed by using the ANSYS 5.7.1, the general commercial program, which is verified as the accuracy and useful characteristic of the solution based on Auto LISP and ANSYS APDL. Both the preprocessor for doing exclusive analysis of filament winding composite pressure vessel and postprocessor that simplifies result of analysis have been developed to help the design engineers.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.11 no.8
• /
• pp.2741-2749
• /
• 2010

This paper presents the impact damage behavior of filament wound composite vessels and the effect of surface protective materials on their impact resistance. Using an instrumented impact testing machine, a series of impact tests was performed on the base panels and the protected panels (panels with surface protective materials of rubber, kevlar/epoxy or glass/epoxy laminates) that were cut from the full scale vessel. And the impact damage parameters were used to identify the effect of protective materials on the damage resistance of composite vessels. Damage resistance of the composite vessels was considerably affected by the protective materials regardless of the shape of the indenters. Among the protective materials, glass/epoxy laminates was the most effective mean for improving the damage resistance of composite vessels.

• Composites Research
• /
• v.15 no.1
• /
• pp.53-60
• /
• 2002

Composite ablative tubes required capabilities of ablative and structural characteristics were fabricated through filament winding technique and several experiments were conducted to evaluate the structural performance of composite ablative tubes. For this purpose, manufacturing procedures were briefly described and then resin digestion method was applied to measure the fiber volume fraction and the void content of composite ablative tubes. The configuration of tensile specimen fur composite ablative tubes with not losing the continuity of reinforced fibers was suggested by evaluating mechanical properties of several types of the specimen with different widths. Also, suitable processing variables for composite ablative tubes were determined by evaluating mechanical properties of several types of the specimen with different processing variables. In addition, acoustic emission signals were obtained during the proof test and could be applicable to study the crack initiation and the damage mode of composite ablative tubes. Finally, the structural reliability of composite ablative tubes could be verified to satisfy design requirements through the proof and burst tests.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.10a
• /
• pp.933-937
• /
• 2002

The fiber reinforced composite material is widely used in the multi-industrial field where the weight reduction of the infrastructure is demanded because of their high specific modulus and specific strength. Pressure vessels using this composite material in comparison with conventional metal vessels can be applied in the field where lightweight and the high pressure are demanded from the defense and aerospace industry to rocket motor case due to the merits which are energy cutdown the weight reduction and decrease of explosive damage preceding to the sudden explosion which is generated by the pressure leakage condition). In this paper, for nonlinear finite element analysis of E-glass/epoxy filament winding composite pressure vessel receiving an internal pressure, the standard interpretation model is developed by using the ANSYS, general commercial software, which is verified as the accuracy and useful characteristic of the solution based on Auto LISP and ANSYS APDL. Both the preprocessor for doing exclusive analysis of filament winding composite pressure vessel and postprocessor that simplifies result of analysis have been developed to help the design engineers.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.25 no.6
• /
• pp.74-86
• /
• 2021

The composite lattice structure is a structure that supports the required load with the minimum weight and thickness. Composite lattice structure is manufactured by the filament winding process using impregnating high-strength carbon fiber with an epoxy resin. Filament winding process can laminate and manufacture only structurally necessary parts, composite lattice structure can be applied to aircraft fuselages, satellite and launch vehicles, and guided weapons to maximize weight reduction. In this paper, the development and evaluation of the composite lattice structure corresponding to the entire process from design, analysis, fabrication, and evaluation of large-scale cylindrical and conical composites lattice structure were performed. To be applicable to actual projectiles and guided weapons, we developed a cylindrical lattice structure with a diameter of 2,600 mm and a length of 2,000 mm, and a conical lattice structure with an upper diameter of 1,300 mm, a lower diameter of 2,500 mm, and a length of 900 mm. The performance of the developed composite lattice structure was evaluated through a load test.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.29 no.5A
• /
• pp.519-529
• /
• 2009

Fiber reinforced composite materials have various advantages in mechanical and chemical aspects. Not only high fatigue and chemical resistance, but also high specific strength and stiffness are attained, and therefore, damping characteristics are beneficial to marine piles. Since piles used for marine structures are subjected to compression and bending as well, detailed research is necessary. Current study examine the mechanical behavior under flexural and/or compressive loads using concrete filled fiber reinforced plastic composite piles, which include large size diameter. 25 pile specimens which have various size of diameters and lengths were fabricated using hand lay-up or filament winding method to see the effect of fabrication method. The inner diameters of test specimens ranged from 165 mm to 600 mm, and the lengths of test specimens ranged from 1,350 mm to 8,000 mm. The strengths of the fill-in concrete were 27 and 40 MPa. Fiber volumes used in circumferential and axial directions are varied in order to see the difference. For some tubes, spiral inner grooves were fabricated to reduce shear deformation between concrete and tube. It was observed that the piles made using filament winding method showed higher flexural stiffness than those made using hand lay-up. The flexural stiffness of piles decreases from the early loading stage, and this phenomenon does not disappear even when the inner spiral grooves were introduced. It means that the relative shear deformation between the concrete and tube wasn't able to be removed.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2001.05a
• /
• pp.193-196
• /
• 2001

The purpose of this study is the design of composite shaft which is wound by Filament Winding method. Classical laminated plate theory was used for analyzing the stress, and for structure design. The diameter and thickness of composite shaft were calculated by this theory. The result that if tensile stress was zero, torsion stress was a certain value below 0.4(diameter rate) and torsion strength was the highest value on $45^{\circ}C$(winding angle). In case of $90^{\circ}C$(winding angle), we have to consider the torsional monent when the composites shaft was load.