• Composites Research
• /
• v.20 no.1
• /
• pp.1-7
• /
• 2007

This study presents a methodology for optimization of static characteristics of golf club shafts. Stacking sequence for the optimal composite shaft performance is searched. A new objective function is defined for the simultaneous optimization of flexural and torsional stiffnesses. Classical lamination theory is used for the static analysis. As the optimization tool, genetic algorithm is applied with the stacking sequence as design. variables. With the optimal stacking sequence, dynamic characteristics of the shaft is also studied.

• Composites Research
• /
• v.31 no.1
• /
• pp.37-41
• /
• 2018

The aim of the current work is to characterise a piecewisely-integrated composite bumper beam based on the IIHS bumper crash protocol. IIHS bumper crash FE analysis for an aluminium type bumper beam was carried out to get the information about the dominant loading types at several regions in the bumper beam during crash. In the meantime, robust stacking sequences against tension and compression have been searched for using FE analysis of a coupon type model. After determining most effective stacking sequences for tension and compression, three-point bending simulation was preliminarily carried out to investigate the combination performance of them. Finally, IIHS bumper crash FE analysis for the piecewisely-integrated composite bumper beam, which consisted of the combination of tension effective stacking sequence and compression efficacious stacking sequence, was conducted and the result was compared with other types of composite bumper beams. It was found that the newly suggested piecewisely-integrated composite bumper beam showed superior crashworthy behaviour to those of uni-modal stacking sequence composite bumper beams.

• Composites Research
• /
• v.36 no.6
• /
• pp.383-387
• /
• 2023

Carbon fiber-reinforced composites have excellent mechanical properties. However, the fracture toughness is a disadvantage due to brittle failure mode. The fracture toughness can be enhanced using hybridization with large-elongation fibers. In this study, polyamide (aramid) fibers are hybridized with carbon fiber with various stacking sequences. As a result, the Izod impact strength was enhanced by 63% with 25% aramid fiber hybridization. It is also shown that there is an optimal point in laminated composite hybridization, [CF/CAF₂/CF]_s stacking sequence.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.12 no.4
• /
• pp.599-606
• /
• 1999

복합 적층 판과 보강 재를 설치한 보강된 복합 적층 패널의 좌굴을 고려한 설계에서, 좌굴이 항상 구조물의 최종 파손을 의미하는 것은 아니므로 이들의 좌굴 및 좌굴 후 거동에 대한 정확한 이해와 연구가 필요하다. 본 연구에서는 유한요소 법을 이용하여 적층 메커니즘과 섬유 배향각, 적층 순서 등이 복합 적층 판과 보강된 복합 적층 패널의 좌굴 및 좌굴 후 거동에 미치는 영향을 체계적으로 해석하였고, 각 변수에 따른 좌굴 및 좌굴 후 거동 특성을 분석하였다.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.12 no.5
• /
• pp.944-951
• /
• 1988

Global-Local Laminate Variational Model is utilized to investigate the characteristics of interlaminar stresses in thick composite laminates under uniform axial extension. Various laminates with different fiber orientation and stacking sequences are analyzed to observe the behavior of interlaminar normal stresses. From this result, the interlaminar normal stress distribution along the laminate interfaces is examined and discussed with an existing approximation model. The repeated stacking of Poisson's ratio symmetric sublaminates is found to be the best stacking method of thick composite laminates to reduce the interlaminar normal stresses for the prevention of the free-edge delamination.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 1992.05a
• /
• pp.139-142
• /
• 1992

• Proceedings of the KSME Conference
• /
• 2007.05a
• /
• pp.28-32
• /
• 2007

Sufficient Conditions are proposed herein for analytically obtaining fully orthotropic (A16=A26=0, Bij=0, D16=D26=0) laminate stacking sequences together with a brief literature survey. A number of specially chosen anti-symmetric balanced stacking sequences are analytically studied, in which all coupling stiffnesses including B16 and B26 are identically zero. Those specially chosen anti-symmetric balanced stacking sequences are then arranged symmetrically with respect to the laminate mid-plane to obtain a number of symmetric stacking balanced stacking sequences of which the elastic stiffnesses are fully orthotropic.

• Composites Research
• /
• v.12 no.4
• /
• pp.17-24
• /
• 1999

Finite element analysis and experiment are performed to investigate residual deformation induced by the repair of composite shell structures using a prepreg patch method. The finite element program is developed on the basis of a three-dimensional degenerated shell element and the first order shear deformation theory. The results analyzed for the laminated shell with free boundary conditions are compared with strains measured during the prepreg patch repair. Final residual stresses occur greatly near the patch when the laminated shell with all edges clamped is repaired using the prepreg patch. Stacking sequences of the laminated shell and patch affect significantly the residual stresses which occur even if they are the same.

• Composites Research
• /
• v.19 no.3
• /
• pp.29-36
• /
• 2006

Since composite materials have anisotropic properties that depend on their stacking angle and sequence, the analysis of joints with isotropic adherends is limited in describing the behavior of the adhesive Joint with composite adherends. In this study, the nonlinear solution for adhesive joints with composite adherends was derived by incorporating the nonlinear behavior of the adhesive into the analysis. The behavior of the laminated composite tube was first analyzed, and the stress distributions of the composite tubular adhesive joint were calculated by including the nonlinear properties of the adhesive. The effect of the stacking sequence of composite adherends and bonding length on torque capacities of joints was examined, and results of the nonlinear analysis were also compared with those of the linear analysis.

• Journal of the KSME
• /
• v.32 no.1
• /
• pp.4-17
• /
• 1992

이 글에서는 복합적층판의 역학적 특성인 층간분리, 모재균열, 초기파손 후의 거동에 대한 문헌을 간단히 서술하고 그 특성을 살펴 보았다. 이상에서 살펴본 바와 같이 이방성인 층으로 구성된 복합적층 구조의 역학적 특성은 균질인 단일구조와 달리 각층의 재료상수가 달라층과 층 사이의 층간응력이 존재하여 층간분리현상이 발생하지 않도록 섬유방향뿐만 아니라 적층순서를 중요한 설계변수로 고려하여야 한다. 또한 모재균열로 인한 기계적 거동의 변화를 이해하고 초기파손 후의 손상을 고려한 해석을 수행하여 복합적층 구조의 응력해석 및 파손, 강도예측을 한다.